往复式和离心式压缩机论文中英文对照资料外文翻译文献
离心式压缩机英文对照
离心式压缩机英文对照阀门valve[v?lv]Shut off valve 截止阀throttle valve ['θr?tl] 节流阀gate valve 闸阀Pneumatic butterfly valve气动蝶阀[nju:'m?tik]Ball vavle 球阀Cock 旋塞阀check valve 止回阀Three way valve 三通阀A安全运转 safe operation安全系数 safe factor安全措施safe precaution[pri'k?:??n]安全阀 safety valveRelief valve安全开关 safety switch放空阀 vent valve安全帽 helment ['helmit]安装 installinstallation装配图 erection drawing[i'rek??n]安装尺寸 installation dimension 安装现场 sit of installation 静载荷 dead load按钮 push button凹凸面法兰male and female flange凹面 concave ['k?nkeiv]B巴氏合金 babbit metal百分误差 percent error百万分之一 part per millionPPM扳手 wrench [rent?]spanner保护气 protective gas保护罩 protective cover报价 proposalTender（投标）报警 alarm备件清单 spare part list壁厚 wall thickness变送器 transmitter 标牌 nameplate 仪表 gauge表面粗糙度 surface roughness [r?f]不锈钢 stainless steel['steinlis]布氏硬度 brinell hardness['brinel]C材料清单 bill of material（BOM）材料检验 inspection of material采购单 purchase order参考标准 reference standard仓库 storehouse槽钢 channel测温仪表 temperature instrument测振动仪 vibrometer [vai'br?mit?] 操作人员operating personnel操作培训 operation training操作维护说明书 operation and Maintenance manual差压计 pressure differential gauge拆卸 disassemble [,dis?'sembl] 产品product厂内试车 shop test run超速试验 over speed testing超压 excessive pressure[ik'sesiv] 齿轮箱gear case/box充氮 nitrogen back filling['naitr?d??n]抽油雾风机oil mist fan出厂试验合格证 mill test Certificate [s?'tifikeit]出口管线outlet nozzle['n?zl]出口压力 outlet pressure除锈除垢 descaling [,di:'skeili?] 传感器sensor ['sens?]喘振 surge喘振控制 surge control敲击 peeningD大齿轮 bull gear大气 atmosphere大修overhaul [,?uv?'h?:l]带法兰接头 flanged end挡板 buffer plate挡块 dog挡圈 locking ring等温压缩机 isothermal compressor [,ais?u'θ?:m?l]低合金钢low alloy steel['?l?i ]低碳钢 mild steel底座 base地脚螺栓 anchor bolt['??k?]电磁阀solenoid valve['s?ul?n?id]电焊 arc welding[ɑ:k]电机启动器 motor starter电机驱动压缩机 motor driven～电缆 cable电流 current电路，管路 circuit电压 voltage ['v?ultid?]电源 power supply垫板 pad垫片 shim/gasket['ɡ?skit]垫圈washer吊车 crane [krein]吊耳lug蝶阀butterfly valve顶部roof顶丝lock screw[skru:]定位器 positioner[p?'zi??n?]定位元件 positioning element电能功率 power动平衡试验dynamic balancing test[dai'n?mik]堵塞blockage ['bl?kid?]镀铬chroming ['kr?umi?]锻钢件 wrought steel [r?:t]锻制管件 forged part [f?:d?]对接焊 butt weld多级压缩机 multiple stageCompressorE二氧化碳 carbon dioxide['kɑ:b?n] [dai'?ksaid]额定流量 rated flow额定输入功率 power input ratingF阀门 valve法兰 flange法兰盖 blind flange量程 range步骤 procedure方位 orientation方向 direction防爆 anti—explosion保证，规定 provision防喘振控制 anti—surge control 防锈剂 rust inhibitor 放空阀 vent valve放空消音器 vent silencer放气阀air-release valve风机、风扇fan腐蚀corrosion [k?'r?u??n] 腐蚀余量 corrosion allowance 附属设备 associated equipment [?'s?u?ieit]辅助油泵 auxiliary oil pump[?:ɡ'zilj?ri]附录 appendix [?'pendiks]负载、载荷 loadG钢管 steel pipe高压缸 high pressure casing高位油箱 oil rundown tankhead oil tank隔板 diaphragm['dai?fr?m]工作电压service voltage功率因数 power factor共振 resonant ['rez?n?nt]供货厂家supplier购买 perchase鼓风机 blower故障排除 trouble shooting['?u:ti?]关闭、切断 shut off管壳式换热器 shell and tube Exchange管路 pipeline惯性矩 inertia moment[i'n?:?i?]灌浆 grouting['ɡrauti?] 规范、说明书 specification 过滤器 filter 过滤器芯子 filter cartridge['kɑ:trid?]过滤器元件 filter elementH海军黄铜 naval brass['neiv?l] [br?s]焊缝 weldWelded joint焊接符号 welding symbol焊渣 welding slag耗电量 power consumption合格证 certificate [s?'tifikeit]合同contract呼吸阀breather valve滑动轴承sliding bearing环境条件ambient condition环氧树脂epoxy [ep'?ksi]灰尘 dust回火 temper回油管 oil return line混泥土 concrete [k?n'kri:t]混泥土基础 concrete foundation J机械效率 mechanical efficiency 级间冷却 interstage cooling ['int?steid?]级效率 stage efficiency计算 calculation夹渣 slag inclusion交货时间表 delivery schedule ['??dju:?l]角钢 angle steel角阀 angle valve角焊接 corner jointfillet weld对中 alignment [?'lainm?nt]接头 joint节流阀throttle valve['θr?tl]结垢 fouling['fauli?]截止阀 shut off valve筋板gusset ['ɡ?sit]紧固件 fastener['fɑ:s?n?]紧急排放阀 emergency dump valve 紧急停车 emergency shut down紧急闸阀 emergency gate valve进口导向叶片 inlet guide vane进口过滤器 suction filter进口过滤网suction filter screen进口温度 suction temperature进气、进料 fed进气量 air inflow进水接管 water inlet nozzle径向间隙 radial clearance['kli?r?ns]就地，局部local就地安装仪local installed instrument 就地表盘local pannel聚四氟乙烯teflon ['tefl?n]PTFE绝对压力 absolute pressureK开度 span开关 switch壳体重量 shell weigh可靠性 reliable [ri'lai?bl]可倾瓦轴承 tilting pad typeBearing空气干燥器 air drier空气分离器 air separation空气冷却器 air cooler孔板 orifice['?rifis]孔板法兰 orifice flange控制表盘 control pannel控制/调节阀 control valve控制仪表 controlling instrument控制原理 control philosophy[fi'l?s?fi]矿物油 mineral oil['min?r?l]扩压器 diffuserL拉杆 tie rod[tai] [r?d]老虎钳 pincer pliers['pins?(r)] ['plai?z]Vice冷凝液 condensate[k?n'denseit]冷却介质cooling medium['mi:di?m,]冷却器cooler冷却水cooling water冷却水耗cooling water consumption冷却水泵～pump离心式压缩机centrifugal compressor[sen'trifjuɡ?l]离心增压机 centrifugal booster 立式 vertical type ['v?:tik?l] 力矩 moment联轴器 coupling列管式换热器 straight tube heat Exchange裂缝 crack/flaw临界温度 critical temperature零部件 component part[k?m'p?un?nt]流程管路process line流程图 process flow sheetflow diagram流量 flow rate流量调节阀 flow control valve硫酸 sulfuric acid[s?l'fju?rik]['?sid]六角螺母hex nut六角头螺栓 hexagon bolt['heks?ɡ?n]漏气 air leakage['li:kid?]户外安装open air installation Outdoors erection [i'rek??n]铝合金 aluminum alloy[?'lju:min?m] ['?l?i]滤芯 filter element螺钉 screw[skru:]罗茨鼓风机 Roots blower螺杆压缩机 screw compressorhelical-lobe compressor螺孔 bolt hole螺母 nut螺栓 bolt螺栓连接 boltingBolted connection螺栓拧紧方法 bolt tightening Procedure[pr?'si:d??]螺栓拧紧扭矩 bolting torque [t?:k]螺纹thread [θred]螺柱 stud （bolt）轮盖 wheel shroud[hwi:l] [?raud]M盲板 dummy plate['d?mi] 盲法兰 blind—flange 毛刺 burr [b?:]密封气 seal gas迷宫密封labyrinth['l?b?rinθ]迷宫密封间隙 labyrinth clearance['kli?r?ns]末端冷却器aftercooler木塞子 wood plug密度 density ['dens?ti]N啮合 mesh [me?] engagement[in'ɡeid?m?nt]扭矩 torque [t?:k]OO型圈 O ringP排放孔 drain opening[drein] 排气温度 exhaust temperature [iɡ'z?:st]排气压力 discharge pressure排污管 blowoff pipe排液 drain盘车 hand rotate machine泡沫 foam [f?um]旁通 by pass旁通阀 by pass valve配对法兰 mating flanges配套厂家 vendor配管技术要求piping specification配合、装配 fit/assemble喷砂 sand blasting喷嘴 spray nozzle膨胀节 expansion joint碰撞 impingement[im'pind?m?nt] 偏差 deviation [,di:vi'ei??n]偏心距eccentricity [,eksen'tris?ti] 频率 frequency剖视图 cutaway viewQ起吊工具 lifting device起重机 hoist away [h?ist]启动时间 start up time气动蝶阀 pneumatic ～[nju:'m?tik] 汽轮机steam turbine氢 hydrogen['haidr?d??n]千分表 dial gauge千斤顶 jack钎焊 braze weldingbrazing['breizi?]前视图 front end view强度试验 strength test强制油润滑 forced oil lubrication[,lu:bri'kei??n]切换阀 switch valve changeover valve球阀 ball valve曲率 curvature['k?:v?t??]取样 sample去毛刺、倒角 deburr全自动防喘振控制 Full automatic anti-surge control缺陷 defectR热电偶 thermocouple['θ?:m?u,k?pl]热电偶插座～well热量heat capacity人孔 man wayMan hole容积流量 volume flow['v?lju:m] 保险丝 fuse[fju:z]入口，吸入suction软管hose [h?uz]软管接头hose coupling锐边sharp edge锐角sharp corneracute angle润滑 lubrication润滑油 lube oil润滑油泵 lube oil pump润滑油加热器 lube oil heater润滑油冷却器 lube oil cooler润滑油站 lube oil console[k?n's?ul]S塞尺 feeler gauge三通阀门 three way valve三相电源 three phase power[feiz]设备 equipment示意图sketch[sket?]设备总布置图overall plantArrangement设备制造厂equipment manufacture 设计标准 design standard 设计参数 design data设计技术规范 design/engineering Specification 设计书 design sheet设计条件～ condition设计图标 design chart设计值 design value设施、设备 facility[f?'siliti] 射线探伤检查 radiographic test[,reidi?u'gr?fik]申请 application生产、产量 production审查 review渗氮 nitriding['naitraidi?, -tri-]渗碳carbonizing['kɑ:b?naiz]渗透penetration [,peni'trei??n] 声光报警acoustical and optical alarm [?'ku:stik?l]湿度humidity [hju:'mid?ti] 石化装置 petrochemical plant[,petr?u'kemik?l]石棉板asbestos sheet/board[?z'best?s]石棉垫片 asbestos gasket实际运行参数 actual operating Data使用寿命 service lifeworking life试车 test run手册 manual手套 gloves[ɡl?v]疏水阀 drain valve数据表 data sheet甩油环 slinger ring['sli??]双面焊 double-sided welding水垢沉积 water fouling deposit['fauli?][di'p?zit] 水击 water hammer ['h?m?]水平度levelness 水蒸汽water vapor['veip?]说明书instruction manual速度velocity [vi'l?s?ti]speed酸洗 pickling['pikli?]锁紧螺母lock-nut塑料的plasticT碳钢 carbon steel天车、行车overhead crane天然气natural gas调节阀regulating valve铁iron停车shut down通气孔air vent同轴度coaxality透平油 turbine oil凸面法兰 raised face flange图号 drawing numberW外观（质量） appearance外径 outside diameter[dai'?mit?] 外壳outside shell外壳，罩housing外形尺寸overall dimension弯道、弯头bend弯头elbow['elb?u]维护方法maintenance procedure 维护说明书maintenance manual 维护需要空间～access spacing位移displacement温差differential temperature温度计thermometer[θ?'m?mit?]温升temperature rise文件document蜗壳spiral casingX现场安装filed installation现场安装管道site erection piping详图detail drawing橡胶rubber项目project项目经理project manager小齿轮pinion效率efficiency新鲜空气fresh water（过滤器）芯子cartridge['kɑ:trid?]型式 pattern性能 performance性能保证 characteristic Guarantee性能曲线 characteristic/performance Curve性能参数 performance parameter [p?'r?mit?]虚线 dashed line许可证 license蓄能器 heat accumulator[?'kju:mjuleit?]旋塞阀 cock询价 inquiry[in'kwai?ri]Y压比pressure ratio['rei?i?u]压差pressure difference压力变送器pressure transmitter 压力表pressure gauge压力表接头～connection压力容器pressure vessel['ves?l]压缩机级compression stage烟道flue [flu:]烟雾 smoking验收acceptance [?k'sept?ns]验收标准 acceptance criteria原理principle ['prins?pl]样品 sample遥控 remote control叶轮 impeller叶轮轮盘 impeller hub叶轮线速度 impeller tip speed 液位计 liquid level gauge液压千斤顶 hydraulic jack [hai'dr?:lik]液压着色检查 dye penetrant test ['pen?tr?nt]异步电机 ychronous motor异径管 reducer仪表 instrument仪表盘 instrument pannel溢流阀 overflow valve硬度 hardness。
Centrifugal compressor
Lesson21 Centrifugal CompressorsThe specific objectives of this lesson are to:1. Explain the working principle of a centrifugal compressor (Section 21.1)2. Present the analysis of centrifugal compressors (Section 21.2)3. Discuss the selection of impeller diameter and speed of a centrifugalcompressor using velocity diagrams (Section 21.3)4. Discuss the effect of blade width on the capacity of centrifugal compressor(Section 21.4)5. Discuss the methods of capacity control of a centrifugal compressor(Section 21.5)6. Discuss the performance aspects and the phenomenon of surging incentrifugal compressors (Section 21.6)7. Compare the performance of a centrifugal compressor with a reciprocatingcompressor vis-á-vis condensing and evaporator temperatures and compressor speed (Section 21.6)8. Describe commercial refrigeration systems using centrifugal compressors(Section 21.7)At the end of the lecture, the student should be able to:1. Explain the working principle of a centrifugal compressor with suitablediagrams2. Analyse the performance of a centrifugal compressor using steady flowenergy equation and velocity diagrams3. Calculate the required impeller diameter and/or speed of a centrifugalcompressor4. Explain the limitations on minimum refrigeration capacity of centrifugalcompressors using velocity diagrams5. Explain the methods of capacity control of centrifugal compressor6. Explain the phenomenon of surging7. Compare the performance aspects of centrifugal and reciprocatingcompressors21.1. Introduction:Centrifugal compressors; also known as turbo-compressors belong to the roto-dynamic type of compressors. In these compressors the required pressure rise takes place due to the continuous conversion of angular momentum imparted to the refrigerant vapour by a high-speed impeller into static pressure. Unlike reciprocating compressors, centrifugal compressors are steady-flow devices hence they are subjected to less vibration and noise.Figure 21.1 shows the working principle of a centrifugal compressor. As shown in the figure, low-pressure refrigerant enters the compressor through the eye of the impeller (1). The impeller (2) consists of a number of blades, whichform flow passages (3) for refrigerant. From the eye, the refrigerant enters the flow passages formed by the impeller blades, which rotate at very high speed. As the refrigerant flows through the blade passages towards the tip of the impeller, it gains momentum and its static pressure also increases. From the tip of the impeller, the refrigerant flows into a stationary diffuser (4). In the diffuser, the refrigerant is decelerated and as a result the dynamic pressure drop is converted into static pressure rise, thus increasing the static pressure further. The vapour from the diffuser enters the volute casing (5) where further conversion of velocity into static pressure takes place due to the divergent shape of the volute. Finally, the pressurized refrigerant leaves the compressor from the volute casing (6).The gain in momentum is due to the transfer of momentum from the high-speed impeller blades to the refrigerant confined between the blade passages. The increase in static pressure is due to the self-compression caused by the centrifugal action. This is analogous to the gravitational effect, which causes the fluid at a higher level to press the fluid below it due to gravity (or its weight). The static pressure produced in the impeller is equal to the static head, which would be produced by an equivalent gravitational column. If we assume the impeller blades to be radial and the inlet diameter of the impeller to be small, then the static head, h developed in the impeller passage for a single stage is given by:gV h 2= (21.1)where h = static head developed, mV = peripheral velocity of the impeller wheel or tip speed, m/sg = acceleration due to gravity, m/s 2Hence increase in total pressure, ΔP as the refrigerant flows through the passage is given by:2V gh P ρ=ρ=Δ (21.2)Refrigerantout3RefrigerantinThus it can be seen that for a given refrigerant with a fixed density, the pressure rise depends only on the peripheral velocity or tip speed of the blade. The tip speed of the blade is proportional to the rotational speed (RPM) of the impeller and the impeller diameter. The maximum permissible tip speed is limitedby the strength of the structural materials of the blade (usually made of high speed chrome-nickel steel) and the sonic velocity of the refrigerant. Under these limitations, the maximum achievable pressure rise (hence maximum achievable temperature lift) of single stage centrifugal compressor is limited for a given refrigerant. Hence, multistage centrifugal compressors are used for large temperature lift applications. In multistage centrifugal compressors, the dischargeof the lower stage compressor is fed to the inlet of the next stage compressorand so on. In multistage centrifugal compressors, the impeller diameter of all stages remains same, but the width of the impeller becomes progressively narrower in the direction of flow as refrigerant density increases progressively.The blades of the compressor or either forward curved or backward curved or radial. Backward curved blades were used in the older compressors, whereas the modern centrifugal compressors use mostly radial blades.The stationary diffuser can be vaned or vaneless. As the name implies, in vaned diffuser vanes are used in the diffuser to form flow passages. The vanescan be fixed or adjustable. Vaned diffusers are compact compared to the vaneless diffusers and are commonly used for high discharge pressure applications. However, the presence of vanes in the diffusers can give rise to shocks, as the refrigerant velocities at the tip of the impeller blade could reach sonic velocities in large, high-speed centrifugal compressors. In vaneless diffusers the velocity of refrigerant in the diffuser decreases and static pressure increases as the radius increases. As a result, for a required pressure rise, the required size of the vaneless diffuser could be large compared to vaned diffuser. However, the problem of shock due to supersonic velocities at the tip does not arise with vaneless diffusers as the velocity can be diffused smoothly.Generally adjustable guide vanes or pre-rotation vanes are added at the inlet (eye) of the impeller for capacity control.21.2. Analysis of centrifugal compressors:Applying energy balance to the compressor (Fig.24.2), we obtain from steady flow energy equation:)gZ 2V h (m W )gZ 2V h (m Q e 2e e c i 2i i +++−=+++− (21.3)where Q = heat transfer rate from the compressorW = work transfer rate to the compressorm = mass flow rate of the refrigerantV i ,V e = Inlet and outlet velocities of the refrigerantZ i ,Z e = Height above a datum in gravitational force field at inlet and outletNeglecting changes in kinetic and potential energy, the above equation becomes:e c i mh W mh Q +−=+− (21.4)In a centrifugal compressor, the heat transfer rate Q is normally negligible (as the area available for heat transfer is small) compared to the other energy terms, hence the rate of compressor work input for adiabatic compression is given by:)h h (m W i e c −=(21.5)The above equation is valid for both reversible as well as irreversible adiabatic compression, provided the actual enthalpy is used at the exit in case of irreversible compression. In case of reversible, adiabatic compression, the power input to the compressor is given by:isen i e isen ,c )h h (m W −= (21.6)then using the thermodynamic relation, Tds=dh–vdp ; the isentropic work of compression is given by:∫=−=PePiisen isen i e isen ,c vdp )h h (w (21.7)Thus the expression for reversible, isentropic work of compression is same for both reciprocating as well as centrifugal compressors. However, the basic difference between actual reciprocating compressors and actual centrifugal compressors lies in the source of irreversibility.In case of reciprocating compressors, the irreversibility is mainly due to eat transfer and pressure drops across valves and connecting pipelines. owever, in case of centrifugal compressors, since the refrigerant has to flow at ery high velocities through the impeller blade passages for a finite pressure rise, e major source of irreversibility is due to the viscous shear stresses at the terface between the refrigerant and the impeller blade surface.In reciprocating compressors, the work is required to overcome the normal rces acting against the piston, while in centrifugal compressors, work is quired to overcome both normal pressure forces as well as viscous shear rces. The specific work is higher than the area of P-v diagram in case of entrifugal compressors due to irreversibilities and also due to the continuouscrease of specific volume of refrigerant due to fluid friction.Fig.21.2. Energy balance across a compressorh H v th info re fo c inTo account for the irreversibilities in centrifugal compressors, a polytropic fficiency ηpol is defined. It is given by: e )h h (vdp w w i e PePiact pol pol −==η∫ (21.8)wherew pol and w act are the polytropic and actual works of compression, respectively.The polytropic work of compression is usually obtained by the expression:⎥⎥⎦⎢⎢⎣−⎟⎠⎜⎝⎟⎠⎜⎝−==∫1Pi Pivi 1n f vdP w n Pi pol (21.9)where n is the index of compression, f is a correction factor which takes into account the variation of n during compression. Normally the value of f is close to 1 (from 1.00 to 1.02), hence it may be neglected in c ⎥⎢⎞⎛⎞⎛Pe n Pe alculations, without gnific behave as an ideal gas, then it can be shown that the polytropic efficiency is equal to:⎤⎡−1n si ant errors.If the refrigerant vapour is assumed to ⎟⎟⎠⎞⎜⎜⎝⎛γ−γ⎟⎠⎞⎜⎝⎛−=η11n n pol (21.10) ific heat ratio, cp/cv (assumed to be constant).above imple equation is often used to obtain the polytropic efficiency of the centrifugal compressors by replacing γ by isentropic index of compression, k, i.e., for actual refrigerants the polytropic efficiency is estimated from the equation:where γ = specThough refrigerant vapours do not strictly behave as ideal gases, the s ⎟⎠⎞⎜⎝⎛−⎟⎠⎞⎜⎝⎛−=ηk 1k 1n n pol (21.11) pressures and specific volumes at the inlet and exit of the ompressor and then using the equation Pv n = constant. This procedure usually ctual efficiency and polytropicFor actual centrifugal compressors, the polytropic efficiency is found to lie in the range of 0.7 to 0.85. The index of compression n is obtained from actual measurements of c gives fairly accurate results for refrigerants made of simple molecules such as water, ammonia. The deviation between aefficiency evaluated using the above equati heavier molecules such as R 22, R 134a ese terms have to ons can be significant in case of .When the refrigerant velocities are high, then the change in kinetic energy across the compressor can be considerable. In such cases, th be included in the steady flow energy equation. If the heat transfer rate is negligible and change in kinetic energy is considerable, then the rate of work input to the compressor is given by:)h h (m W i ,t e ,t c −=(21.12)where h t,e and h t,i are the total or stagnat d inlet to the compressor, respectively. The stagnation enthalpy of the refrigerant h t is given y:ion enthalpies at the exit an b 2V h h 2t += (21.13)where h is the specific enthalpy of the refrigerant and V is its velocity. Similar to stagnation enthalpy, one can also define stagnation temperature and stagnation pressure. The stagnation pressure P t is defined as the pressure developed as the frigerant is decelerated reversibly and re adiabatically from velocity V to rest. Then from energy balance,2V h h vdp 2t Pt P isen =−=∫(21.14)Stagnation pressure and temperature by pressure and temperature sensors moving h the e same velocity. of moving fluids can be measured wit fluid at th For an ideal gas:)T T (Cp 2V )h h (t 2t −==− (21.15) where T t is the total or stagnation te mperature given by:Cp2V T T t += (21.16)where T is the static temperature and Cp is the specific heat at constant pressure.2For an incompressible fluid (density ≈ constant):)P P (v 2t Pisen hence the stagnation pressure of an incompressible fluid is given by:V vdp 2Pt−≈=∫ (21.17) vV 21P P 2t += (21.18)21.3. Selection of impeller speed and impeller diameter: As the refrigerant vapour flows from the suction flange to the inlet to the impeller, its stagnation enthalpy remains is done during this section. However, the velocity of the refrigerant may increase due to reduction in ow area. Depending upon the presence or absence of inlet guide vanes in the between the impeller blades from the inlet. As the refrigerant flows rough the blade passages its stagnation enthalpy rises as work of compression supplied to the refrigerant through the impeller blades. Simultaneously its momentum transfer and self-es as the refrigerant flows towards the tip. From the tip of the impeller the refrigerant enters the diffuser, w ure increases further due to deceleration, however, its total enthalpy remain s no refrigerant nters the volute casing where further pressure rise takes place due to conversion of velocity into static pressure, while the total enthalpy remains constant as no energy is added to th asing. Thus the total enthalpy of the refrigerant remains constant everywhere except across the peed . This alls for application of conservation of angular momentum equation to theconstant as no work fl eye of the impeller, the refrigerant enters the impeller with a pre-rotation or axially. Then the direction of the refrigerant changes by 90o as it enters the flow assages p th is velocity and static pressure rise due to the ompression. However, the relative velocity between refrigerant and impeller c blades usually reduc here its static press s constant a energy transfer takes place to the refrigerant. From the diffuser the e e refrigerant in the volute c impeller. To establish a relation between the power input and the impeller s and diameter, it is essential to find the torque required to rotate the impeller c refrigerant across the impeller.Figure 21.3 shows the velocity diagram at the outlet of the impeller. The torque required to rotate the impeller is equal to the rate of change of the angular momentum of the refrigerant. Assuming the refrigerant to enter the impeller blade passage radially with no tangential component at inlet, the torque τ is given by:2,t 2V mr =τ(21.19)where m is the mass flow rate of the refrigerant, r 2 is the outer radius of the impeller blade and V t,2 is the tangential component of the absolute refrigerant velocity V 2 at impeller exit. The power input to the impeller W is given by:2,t 22,t 2V mu V mr .P =ω=ωτ= (21.20)where u 2 is the tip speed of the impeller blade = ω.r 2. ω is the rotational speed in radians/s and r 2 is the impeller blade radius.21.3: Velocity diagram at the outlet of the impeller of a centrifugalcompressorThe velocity diagram also shows the normal component of refrigerant velocity,V n,2 at the impeller outlet. The volume flow rate from the impeller is proportionalto the normal component of velocity. From the velocity diagram the tangentialcomponent V t,2 can be written in terms of the tip speed u 2, normal componentV n,2 and the outlet blade angle β as:⎟⎟⎠⎞⎜⎜⎝⎛β−=β−=22,n 22,n 22,t u cot V 1u cot V u V (21.21) Hence the power input to the impeller, W is given by:⎟⎟⎠⎞⎜⎜⎝⎛β−==22,n 222,t 2u cot V 1mu V mu W (21.22) Thus the power input to the compressor depends on the blade angle β. Theblade angle will be less than 90o for backward curved blade, equal to 90o forradial blades and greater than 90o for forward curved blade. Thus for a givenimpeller tip speed, the power input increases with the blade angle β.If the blades are radial, then the power input is given by:o 2222,n 2290for ;mu u cot V 1mu W =β=⎟⎟⎠⎞⎜⎜⎝⎛β−= (21.23) If the compression process is reversible and adiabatic, then power input can alsobe written as:∫=−=PePiisen isen i e isen ,c vdp m )h h (m W (21.24)Comparing the above two equations:2222PePi isen isen i e )r (u vdP )h h (ω===−∫ (21.25)The above equation can also be written as:22k 1k Pe Pi isen )r (1Pi Pe Pivi 1k k vdP ω=⎥⎥⎥⎦⎤⎢⎢⎢⎣⎡−⎟⎠⎞⎜⎝⎛⎟⎠⎞⎜⎝⎛−=−∫ (21.26)Thus from the above equation, the pressure ratio, r p = (Pe/Pi) can be written as:1k k 22p )r (Pivi 1k 1k 1Pi Pe r −⎥⎦⎤⎢⎣⎡ω⎟⎠⎞⎜⎝⎛⎟⎠⎞⎜⎝⎛−+=⎟⎠⎞⎜⎝⎛= (21.27)Thus it can be seen from the above expression that for a given refrigerantat a given suction conditions (i.e., fixed k, Pi and vi), pressure ratio is proportionalto the rotational speed of the compressor and the impeller blade diameter.Hence, larger the required temperature lift (i.e., larger pressure ratio) largershould be the rotational speed and/or impeller diameter.Generally from material strength considerations the tip speed, u (=ωr 2) islimited to about 300 m/s. This puts an upper limit on with asingle stage centrifugal compressor. Hence, for larger temperature lifts requiretional speed and impelleriameter, the pressure rise also depends on the type of the refrigerant used.For example2 the temperature lift multi-stage compression. For a given impeller rota d , for a single stage saturated cycle operating between an evaporatoro o with highero its ban.Similar type of analyses can be carried out for other types of blades (i.e.,forward or backward) and also with a pre-rotation at impeller inlet (i.e., V t,1 ≠ 0).In actual compressors, the angle at which fluid leaves the impeller β’ willbe different from the blade angle β. This is attribut ofrefrigerant in the flow passages between the impeller blades. As the refrigerants, a pressure gradient is developed acrosse flow passage due to the Coriolis component of acceleration. Due to thispressure difference, eddies form in the flow channels as shown in Fig.21.4. Asshown, these eddies rotate in a direction opposite to that of the impeller, as aresult the actual angle β’ at which the refrigerant leaves the impeller will be lessangential component of velocity V t,2duces, which in turn reduces the pressure rise and also the volumetric flow rateof refrigerant. The ratio of actual tangential velocity component (V t,act ) to thetangential component without eddy formation (V t,2) is kno heslip factor can be increased by increasing the number of blades decreasing the area of individual flow passages), however, after a certainumber of blades, the efficiency drops due increased frictional losses. Hence, thelsses.temperature of 0C and a condensing temperature of 32C, the required tipspeed [V t,2 = (he-hi)isen 1/2) will be 145.6 m/s in case of R134a and 386 m/s incase of ammonia. If the impeller rotates at 50 rps, then the required impellerradius would be 0.4635m in case of R 134a and 1.229m in case of ammonia. Ingeneral smaller tip speeds and impeller size could be obtained normal boiling point refrigerants. This is the reason behind the wide spread useof R 11 (NBP = 23.7o C) in centrifugal compressors prior tHowever, the actual analyses can be quite complicated if one includes the pre-rotation guide vanes, slip between the refrigerant and impeller blades etc.ed to the internal circulation flows outwards along a rotating radiu th than the blade angle β. Due to this, the t re wn as slip factor. T (i.e., byn number of blades are normally optimized considering the slip factor and frictiona loFig.21.4: Formation of eddies in a backward curved centrifugal compressor21.4. Refrigerant capacity of centrifugal compressors:The refrigerant capacity of a centrifugal compressor depends primarily onthe tip speed and width of the impeller. For a given set of condenser andevaporator temperatures the required pressure rise across the compressorremains same for all capacities, large and small. Since the pressure rise dependson the impeller diameter, number of impellers and rotational speed of the impeller, these parameters must remain same for all compressors of allcapacities operating between the same condenser and evaporator temperatures.The mass flow rate through a centrifugal compressor can be written as:2p ,f 2,n v A V m = (21.28) where V n,2 = Normal component of velocity at the exitA f,p = Flow area at the peripheryv 2= Specific volume of the refrigerant at the peripheryFor a given blade diameter, the flow area at the periphery depends on thenumber of blades and the width of the blade. If the number of blades is fixed,then the flow area depends only on the width of the impeller.Hence, one way to design the compressors for different refrigerant capacities is by controlling the width of the impeller (Fig.21.5). To design the compressor for smaller refrigerant capacity, one has to reduce the width of the impeller. However, as the width of the impeller is reduced frictional losses between the refrigerant and impeller blades increase leading to lower efficiency. Of course another alternative is to reduce both diameter and width of the impeller simultaneously, thereby the frictional losses can be reduced. However, since this reduces the pressure rise across a single impeller, one has to increase the number of stages, which leads to higher manufacturing costs. This puts a lower limit on the refrigerant capacity of centrifugal compressors. In practice, the lower volumetric flow rate is limited to about 0.7 m3/s and the minimum refrigeration capacities are around 300 kW for air conditioning applications. Since the compressor works more efficiently at higher volumetric flow rates, refrigerants having lower densities (i.e., higher normal boiling points) such as R 11, water are ideal refrigerants for centrifugal compressors. However, centrifugal compressors in larger capacities are available for a wide range of refrigerants, both synthetic and natural.21.5.Capacity can also be controlled by varying the compressor speed usinggear drives. For the same pressure rise, operating at lower speeds reduces theflow rate, thereby reducing the refrigeration capacity.Capacity control:The capacity of a centrifugal compressor is normally controlled byadjusting inlet guide vanes (pre-rotation vanes). Adjusting the inlet guide vanesprovide a swirl at the impeller inlet and thereby introduces a tangential velocity atthe inlet to the impeller, which gives rise to different refrigerant flow rates. Figure21.6 shows the performance of the compressor at different settings of the inletguide vanes. Use of inlet guide vanes for capacity control is an efficient methodas long as the angle of rotation is high, i.e., the vanes are near the fully opencondition. When the angle is reduced very much, then this method becomesinefficient as the inlet guide vanes then act as throttling devices.In addition to the inlet guide vanes, the capacity control is also possible byadjusting the width of a vaneless diffuser or by adjusting the guide vanes ofvaned diffusers. Using a combination of the inlet guide vanes and diffuser, thecapacities can be varied from 10 percent to 100 percent of full load capacity.Fig.21.6: Effect of angle of pre-rotation vanes on capacity of a centrifugalcompressor21.6. Performance aspects of centrifugal compressor:elow the idealharacteristic curve without losses, and it also shows an optimum point. Theoptimum point at which the losses are minimum is selected as the design pointenser pressures can beifferent from their design values. For example, the condenser pressure mayFigure 21.7 shows the pressure-volume characteristics of a centrifugalcompressor running at certain speed. As shown in the figure, the relationbetween pressure and volume is a straight line in the absence of any losses.However, in actual compressors losses occur due to eddy formation in the flowpassages, frictional losses and shock losses at the inlet to the impeller. As aresult the net head developed reduces as shown in the figure. The entry lossesare due to change of direction of refrigerant at the inlet and also due to pre-rotation. These losses can be controlled to some extent using the inlet guidevanes. Due to these losses the net performance curve falls b c for the compressor.VolumeFig.21.7: Pressure-volume characteristics of a centrifugal compressor runningat certain speedSurging:A centrifugal compressor is designed to operate between a givenevaporator and condenser pressures. Due to variations either in the heat sink orrefrigerated space, the actual evaporator and cond dincrease if the heat sink temperature increases or the cooling water f educes. If the resulting pressure difference exceeds the design p low rateressurey to occur when the refrigeration load isompressor, it decreases with condensing temperature for a centrifugalr. This is due to the rapid drop in refrigerant mass flow rate ofentrifugal compressor with condensing temperature. This characteristic impliesr difference of the compressor, then refrigerant flow reduces and finally stops.Further increase in condenser pressure causes a reverse flow of refrigerant fromcondenser to evaporator through the compressor. As a result the evaporatorpressure increases, the pressure difference reduces and the compressor onceagain starts pumping the refrigerant in the normal direction. Once the refrigerantstarts flowing in the normal direction, the pressure difference increases and againthe reversal of flow takes place, as the pressure at the exit of compressor is lessthan the condenser pressure. This oscillation of refrigerant flow and the resultingrapid variation in pressure difference gives rise to the phenomenon called“surging ”. Surging produces noise and imposes severe stresses on the bearingsof the compressor and motor, ultimately leading to their damage. Hence,continuous surging is highly undesirable, even though it may be tolerated if itoccurs occasionally. Surging is most likel low (i.e. evaporator pressure is low) and/or the condensing temperature is high.In some centrifugal compressors, surging is taken care of by bypassing a part ofthe refrigerant from the discharge side to the evaporator, thereby increasing theload artificially. Thus a centrifugal compressor cannot pump the refrigerant whenthe condensing pressure exceeds a certain value and/or when the evaporatorpressure falls below a certain point. This is unlike reciprocating compressors,which continue to pump refrigerant, albeit at lower flow rates when the condensertemperature increases and/or the evaporator pressure falls.Figures 21.8(a) and (b) show the effect of condensing and evaporatingtemperatures on the performance of centrifugal compressors and reciprocatingcompressors. It can be seen from these figures that beyond a certain condenserpressure and below a certain evaporator pressure, the refrigerant capacity ofcentrifugal compressor decreases rapidly unlike reciprocating compressorswhere the capacity drop under these conditions is more gradual. However, oneadvantage with centrifugal compressor is that when operated away from thesurge point, the reduction in evaporator temperature with refrigeration load issmaller compared to the reciprocating compressor. This implies that theevaporator temperature of the refrigeration system using a centrifugalcompressor remains almost constant over wide variation of refrigeration loads.Figure 21.9 shows the effect of condensing temperature on power inputfor both reciprocating as well as centrifugal compressors at a particularevaporator temperature and compressor speed. It can be seen that while thepower input increases with condensing temperature for a reciprocatingc compresso c that the problem of compressor overloading at high condensing temperaturesdoes not exist in case of centrifugal compressors.。
电气自动化专业毕业设计外文翻译(中英文对照翻译)-制冷压缩机速度的模糊控制
毕业设计（论文）外文翻译Fuzzy Control of The Compressor Speed in aRefrigeration plant制冷压缩机速度的模糊控制制冷压缩机速度的模糊控制摘要在这篇文章里，所提到的是在通常应用于商业上的蒸汽压缩制冷装之中，用模糊控制算法控制制冷压缩机的速度使之达到最有效的速度来控制冷气的温度。
它主要的目标是根据模糊控制算法，通过变换器对压缩机速度进行连续调控，并估算节能效果；不同于传统恒温控制，这里通过控制压缩机冷藏容量，施加给控制压缩机50Hz的开关运转频率。
通过控制压缩机的电动机的供电电流达到的速度变化范围是30-50Hz，由于转动频率过低会有因飞溅系统而出现的润滑问题，现今所提供的压缩机转动频率一般不考虑小于30Hz的。
在这个范围，在二个最适当的工作流体之中，可以代替R22有很多，例如R407C (R32/R125/R134a 23/25/52%组)和R507 (R125/R143A 50/50%组)比较好。
压缩机速度模糊控制与传统的温度控制相比，更多的用于冷藏和其他制冷系统。
实验结果表明，当R407C 作为工作流体时，可以达到显著的节能效果，( 13%)。
值得注意的是，从节能观点看，当压缩机速度变化时可以达到的最佳的效果。
另外，考虑到变换器费用问题，回收期要比可接受的产品型号更具有决定性。
关键词：压缩系统; 冷室; 活塞式压缩机; 易变的速度; 章程; 模糊逻辑;R407C; R5071引言蒸气压缩冷却装置，虽则被设计满足最大载荷，但为了延长寿命，通常在部分装载下工作，并通过开关周期调控，在50 Hz的频率下运作，这样就决定了高能消耗量的恒温控制。
而且，制冷时耗电量低被认为间接的释放了温室气体; 改进上述的系统的能量转换效率可以减少这种排放物。
各种各样的冷藏容量控制方法和部分装载理论表明压缩机速度变异是最高效率的技术。
[1,2]。
冷藏容量控制这个方法在最近3–10年已经被分析研究，包括提高压缩机的速度以不断的达到制冷效果。
关于洗衣机的毕业外文文献翻译、中英文翻译、外文翻译
外文翻译资料外文原文：Washing machinesLet’s look inside one of today’s fully automatic washing machines that use swirling water to clean the clothes. There are many types of washing machines but this Figure shows you what most of them are basically made up of.。
The reason why a washing machine like this can wash and get the water out of the clothes at the same time is because it has a double layer drum.When1washing and rinsing,the pulsator spins and makes the water swirl..To get the water out of the clothes, the inner wall f the drum spins and the water goes through the holes.These days,the“centrifugal force washing machines”are quite popular.This type of machine does not use a pulsator.Instead,the inner wall spins really quickly.1外文翻译资料When the drum spins,the dirty clothes get stuck to the wall.The water and detergent also try to escape through the holes of the wall but before they do so,they are forced to escape through the clothes.When this happens,the power of the water and detergent removes the dirt form the clothes.Another good thing about this type of machine is that clothes don’t get tangled up so you don’t have to worry about your clothes getting ripped or damaged.Next,let’s look at some different types ofwashing machines!Many of you probably think that the water inside washing machines goes round and round. Actually, different washing machines make water flow in different ways.Whirlpool type:This type of washing machine uses a pulsator to force the water to move like a whirlpool inside the Drum.The spinning water forces the dirt out form the clothes inside the machine. Some of the newer models of this type also make the whirlpool move up and down to make it clean clothes even better!Agitator stirring typeThis type of washing machine has something that looks like a propeller at the bottom of the tub.This Propeller spins around and stirs the water.The water then forces the dirt out from the clothes in the machine.The good thing about this type of machine is that clothes do not get tangled up and clothes get evenly washed.Drum type:This type of machine has a drum with many holes in it. There are also protrusions bumps on the wall of the drum.As the drum turns,the clothes are picked up by the protrusions. When the clothes fall down from the top of the drum through the water,the movement removes dirt from the clothes.Centrifugal force type:2外文翻译资料As we have said before, the spinning drum pushes the water and detergent out through the wall of the inner drum. The power that comes form spinning the drum is called centrifugal force., which is where the name comes from. The water is forced through the clothes and then the holes in the inner wall.After one cycle,the water is recycled back into the tank and the process starts again.This cycle is what cleans the clothes!In Japan,people first started using machines in1930.But then the price of a washing machine was so high that most average persons could not buy one for their homes.Looking back now, there was something strange and funny on some of the first versions of the washing machine .The machine had two rollers that were used to sandwich each shirt and other clothes to squeeze the water out of them.The rollers were turned by hand,and in fact,you needed a lot of strength to turn those things!Still,people then thought it was a really neat invention!This type of water squeezer was used for almost 30 years until something new came along. The spin drier that used“centrifugal force”to get most ofthe water is out of the clothes.In1953,the nozzle type washing machine was first sold in Japan.This washing machine is like the older brother of the swirling washing machine that you see today. The price of these washing machines was lower and because of this, more people bought them. The first fully automatic washing machine was introduced in1968,and after that,washing clothes became a lot easier to do!There are a lot of different types of washing machines. What kind of washing machine do you have in your house?Fully automatic:The fully automatic machine has two drum layers that wash, rinse and removewater from clothes together. All you have to do is add detergent and put in dirty3外文翻译资料clothes and then washing machine will do the rest.There is also a new type of fully automatic washing machine that can dry clothes after they have been washed.Twin tub:This washing machine has one part that dose the washing and another part that does the squeezing.Even though it’s a hassle to take the clothes out and move them to other tub,the good thing is that you can wash and squeeze at the same time with one machine.Front loading:The main feature of front loaders is that they use a lot less water than other types.This is the type of Washing machine that dry cleaners use but a lot of people in western countries have this type of washing machine in their homes too.Let’s try to make the best washing machine in the world!We should already thank the scientists that invented the fully automatic washing machine because it makes washing clothes a piece of cake.Scientists are still trying really hard to find ways to make washing machines a lot handier to use for everyone.Some of the things that they are trying to do are to find better ways of making clothes clean and ways to make washing machines last longer.There are washing machines with d trying function today so you don’t even have to hang clothes after words because it dries them automatically!Amazing!Scientists are also trying to find ways to use less water and less detergent in washing machines at present.This is because that it is better to use less water for preserving the environment.What are washing machines of the future going to be like? Maybe there will be a washing machine that dries and folds your clothes after washing them,or maybe there will be one that will wash your clothes while you are still wearingthem! How handy would that be! Remember, if the first washing machine was like4外文翻译资料a dream to people in the old days, all the dreams you have about washing machines of the future may come true!Now, washing machine is becoming more and more popular. We see the main classification.Washing machine can be divided into automatic type and semi-automatic type two kinds, automatic type washing machine as long as we begin our work proactively set better washing procedure,washing machine began to work until the end without manual intervention. And semi-automatic washing machine washing and dewatering process is divided,is also called the double barrel washing machine, a tong,one takes off a bucket,and put tong inside washing out to artificial add to take off in the barrel dehydration is handled and complete laundry process.Full-automatic washing machine in structure to take off in tong internal bucket suit, two barrels of axis,while working with the clutch to finish washing state and dehydration of the transition of the states,on the key said is automatic washing machine.Full-automatic washing machine press catharsis means to points,can be dividedinto bunt washer and roll barrel type two kinds of washing machine, From the electric control ways to points,can be divided into mechanical program-controlled type and computer board controls type washing machine two kinds.The cylinder and the pulsator washing machine are now the main two kinds.Pulsator washing machine working principle is to add clothing,then open the inlet valve,choose good bibcock of water level and correct working procedures, switch on the power,closed warehouse door,and safety switch closed at water level,the public internal switch contacts are and dehydration contacts are interlinked,inlet valve electrify water,when the barrel water reaches the specifiedheight,in air pressure under the action of water level switch inside public contacts5外文翻译资料disconnect dehydration contacts and connect washing contacts,feed valve power to stop water,motor power is switched on,motor started running,and periodically sometimes are turning,sometimes reverse,mutual alternant,driven by clutch BoLun using the same cycle are turning,inversion,with a certain speed rotating BoLun can drive inside bucket of water and clothing,clothing rotating water formed in the mutual friction and reach the purpose of laundry. When washing process is completed,drainage electromagnetic valve electrify work,drain valve is opened,inside bucket of water exudes,and linkage shaft also the clutch from washing state switch to dehydration state,when drainage is completed,atmospheric pressure drop and inside bucket of water level switch public contacts reset through dehydration contacts,drainage electromagnetic valve keep electrify state,motor driven off running electrify bucket high-speed andjilt dry clothing,laundry program after washing machine disconnect hydropower and stop. As for intermediate process of how many times, laundry to wash the length of time, by process control.Roller-type washing machine of the principle and Pulsator washing machine are basic similar.But110mm drum machine it no clutch variable speed,but its motor is double-speed motor, so when washing machine work in washing state, program-controlled device connected motor washing low-speed windings, motor speed slow, working on dehydration, when they connect dehydration modal high-speed windings,motor high-speed operation,this process is programmed through the device and motor to work together to finish.To sum up, the role of these two kinds of washing machine is same, but different implementation,each has his strong point,Pulsator washing machine is simulated handmade kneaded action to work, 110mm drum type washing machine is by gravity inertial function to finish our work,they realize washing and6dewatering way also have different features,Pulsator washing machine to wear clothes is relatively large,but detergents degree is higher,110mm drum machine for clothing wear small,but detergents degrees,but lower than Pulsator washing machine to save water.So far,washing machine is still towards a higher requirements development.7译文：洗衣机来看一下涡流式全自动洗衣机的构造。
往复式压缩机数据单站专业词汇中英文对照
往复式压缩机数据单站专业词汇中英文对照Stainless stell hex bolt , hex socket bolt , hex nut , cap nut wing nut , locknut and other stainless stell fasteners, including non-standard fasteners .不锈钢外六角螺栓，内六角螺栓，六角螺母，盖型螺母，蝶型螺母，防松螺母，吊环，活节螺栓，螺丝Terminology In Reciprocating Compressors Datasheetdriver nameplate kw 驱动机铭牌功率kwno negative tolerance applies 无负偏差Max acceptable piston speed 活塞最大最高许用速度Pulse device 脉动抑制装置pulse suppress Inlet 压力脉动抑制装置进口处Certified PT 保证点Pressure at cylinder flange 在汽缸法兰处压力Side stream temp 旁流温度Compressibility 压缩系数（压缩比）TEMP ADIABATIC 绝对温度as built 竣工proposal 投标Total Bkw at compressor shaft 总功率kw在压缩机轴处Capacity for NNT 无负偏差的容积流量Even minute traces 仅有微量Elevation 海拔高度at grade level 级水准winterization required 要求防冻Partial Sides 部分侧墙Electrical Classification 电器分类Class ____ Group ____ Zone 区____组_____级Main unit 主机L.O Console润滑油站CW Console 冷却水站POCKETS/Valves Operation 余隙腔/阀门开启Type Unloaders, Plug/Finger 卸荷器类型塞式/指式Combined Rod Load C 综合活塞杆负荷(压缩)Combined Rod Load T 综合活塞负荷（拉伸）Auto Loading Delay Interlock 自动负荷延迟联锁Outboard bearing 外置轴承Slide base for driver 电机导轨座Sole plate for driver 驱动机底座Key less drv 无键驱动Quilt shaft 套筒轴Drive Guard 传动装置护罩Compressor Valves Dynamic Response 压缩机气阀动态响应skid, soleplate, baseplate 底架，底版，底座leveling screw 调节螺钉Column mouting 立柱安装Bolts or Studs for soleplate to frame用于机身和底板的螺栓或双头螺栓Rail 导轨Chock block 垫块垫片shimsdirect grounted 直接灌浆Cement/Mortar Grout水泥/沙浆浇灌off mounted 分别安装Flange finish 法兰光洁度Inlet strainer 进气过滤器manifold piping 集合管spool piece for inlet strainer 进气过滤器套筒Thermosyphon 热虹吸Match marked 配合标记One CMMN to all unites 所有设备共用一个Dual filters with transfer valves带转换阀的双联过滤器Seperated machine mounted panel 独立的机器安装控制盘Seperated free standing panel 独立的自由防止控制盘Cyl. LUBRICATORS 汽缸注油器Hydraulic tension tools 液压安装工具US Customary Units 美国常用单位Barring device 盘车装置Instrument air 仪表风Single or double acting 单作用或双作用Bore 缸径Stroke 行程Cylinder Liner 钢套Piston displacement 活塞排量Volumetric efficiency 容积效率Liner nominal thickness 钢套公称厚度Rod REV DEGREE 活塞反向角Facing 法兰面Wear bands 支撑环Thread roots stress 螺纹根部应力Rod pressure packing ring 杆压力填料环Rod pressure packing case 杆压力填料函Seal/buffer packing distance pieces 密封/缓冲填料，机身中体隔离wiper packing ring 刮油环Main Journal Bearing 主轴颈轴承Connecting Rod Bushing, Crankpin 曲轴销连杆轴承Crosshead shoes 十字头滑板crosshead pin 十字头销crosshead pin bushing 十字头销套筒Vented to flares 放空至火炬Fluorocarbon sprayed cylinder 氟塑料喷涂汽缸Splash guards for wiper packing 刮油防溅罩Distance plate MAWP 中体最大允许工作压力。
毕业论文外文翻译-小型制冷压缩机研究
Small COMPRESSORCompressor refrigeration system is the core and heart of its decision to the refrigeration system capabilities and features. This paper not only energy efficient, noise and vibration and refrigeration agent analyzed small refrigeration compressor technical performance, Analysis also have appeared in recent years, the new, special small compressor main feature for us small refrigeration compressor future development trend of laying a technological foundation.As we all know, the compressor refrigeration system is the core and heart. Compressor and decided that the cooling system capacity and features. In a sense, the cooling system design and matching of the compressor is the ability demonstrated. Therefore, countries in the world are all in the refrigeration industry refrigeration compressor research invested a tremendous amount of energy, new research direction, and research results continue to emerge. Compressor technology and performance level with each passing day.1.A compressor Efficiency StudyCompressor refrigeration system is the core energy components, improve the efficiency of refrigeration systems of the most direct and effective means is to increase the efficiency of the compressor, It will bring the energy consumption decreased significantly. Moreover, can only avoid the system take measures (such as simply increasing heat exchanger area, etc.) caused by the consumption of materials increased. In recent years, as world energy shortage situation worsens day by day, more and more attention to various energy-saving work the energy efficiency of products made by the ever-increasing demands. Due to losses such as friction, leakage, harmful heat, the electrical loss, flow resistance, noise vibration of existence, Compressor work far below the actual efficiency of theoretical efficiency. Therefore, from a theoretical point of view, any reduction in a loss of arbitrary measures toimprove the efficiency of the compressor. The objective facts have led to the energy saving compressor scope, direction, width, research topics and results varied.On the current international energy-efficient compressors research concentrated mainly in a few areas : research lubrication properties Compressor parts of the friction bearings to reduce friction characteristics of power, improve the efficiency of the compressor; reduce leakage losses to improve the efficiency of the compressor; using frequency modulation technology or refrigeration system through the effort with the user load to match the best energy saving In this regard the particular frequency technology has been relatively mature well known and not repeat them here. Valve Research is an old topic but it is also an eternal topic, Improvement of the valve designed to improve the efficiency of the compressor also Nagamochi endless harvest. Research in this area many times, from the valve material, sports law, optimizing the structure of the applicable theory, exhaustive testing methods. In short, energy-saving compressors on the research in recent years has become one of the refrigeration industry first hot issues.In recent years, domestic refrigeration compressor industry to studyenergy-saving products are also giving great concern. Progress larger products mainly refrigerator compressor industry. In China efficient refrigerators GEF projects to promote and support, both the enterprises for energy-efficient products is the understanding of the performance of refrigerator compressors have a qualitative leap. At present, domestic enterprises refrigerator compressor products of the highest energy efficiency has reached 1.95%. Refrigerator compressor domestic enterprises to take a lot of technical measures such as high efficiency motors or synchronous motor, concave valves, Plane thrust bearing, low viscosity lubricants, the new Getter muffler, reducing friction losses, and achieved great results. The main problem is the lack of domestic enterprises currently free technology, the technology has to imitate the line mainly, Most of the enterprises to build their own technology infrastructure alsounconscious, nor the interest, and this restricts the development of technological capacity.Relative to the refrigerator compressor industry, domestic energy-efficientair-conditioning compressor study it was not perturbed, Over the years the efficiency of the compressor is no substantive change, greater market demand makes most of the air-conditioning compressor enterprises will concentrate on expanding production on. With the nation on the air conditioner energy efficiency standards set for the further improvement of China's air conditioner exports various perils of showing, domestic air-conditioning compressor of this short-sighted enterprises will be unable to adapt to the energy-saving development of the situation. Enterprise also on the follow-up is weak.2. Compressor noise and vibration studyCurrently, the noise has been regarded as one of the serious pollution. Household refrigeration equipment as the source of power and heart, refrigeration compressor noise, to be a measure of its performance as an important indicator. In fact, to a compressor speaking, Most of the noise is due to shell by some noise from the source excitation (such as springs, refrigerant pressure pulsation, exhaust pipe, lubricants etc. excited). But compressor noise sources and pathways complex and diverse, which gives the compressor noise silencer brought great difficulties.On the compressor noise, vibration and foreign scholars have conducted a large number of long-term research. Here in this regard to the main research results are summarized below :The main refrigeration compressor noise Exaggerative inlet, exhaust radiation aerodynamic noise, mechanical moving parts of machinery noise and noise-driven motor three components :2.1 Aerodynamic noiseCompressor inlet airflow noise is due to the intake manifold pressure pulsation in the elections. Inlet-frequency noise and the intake manifold gas Lane same frequency pulsating with the speed of the compressor. Compressor exhaust noise is due to air in the exhaust pipe caused by fluctuating pressures. Exhaust noise than the inlet noise weak, so the compressor aerodynamic noise generally Inlet mainly noise2.2 Mechanical NoiseCompressor mechanical noise, including members of the general impact and friction, the piston vibration, noise impact of the valve, These noise with randomness, was puted.2.3Electromagnetic noiseCompressor electromagnetic noise is generated by the motor. Motor noise and aerodynamic noise and mechanical noise is weaker compared. Noise source compressor inlet, exhaust, aerodynamic noise, the strongest, followed by mechanical noise and electromagnetic noise. Through in-depth studies, we can further that the main compressor noise from the vibration (from the Department of spring, Refrigeration medium pressure pulsation and smoke exhaust pipe and lubricants have incentive) to the ambient medium spread formation noise. On the effort to reduce compressor noise, much of the literature (abbreviated) proposed a series of measures and the Noise and Vibration Reduction program :① increase rigid shell structure to improve the overall resonance frequency reduces vibration amplitude;② curvature of the shell to avoid mutation, the surface, and the natural frequency is inversely proportional to the radius of curvature. shell shape it should be the smallest curvature radius;③ spring bearing flags will be moved to higher rigid position;④ shell should be used as little as possible of the plane; bending stress and the stress coupling membrane (just on the surface) will shell itself is fairly rigid. Therefore compressor shell to be used as little as possible planar structure;⑤ avoid the exhaust pipe and condenser incentive, optimizing exhaust flow pulsation, Exhaust pipe used in the introduction of additional volume to the elimination of pressure fluctuation spectrum of high-order harmonics;⑥ non-symmetric shell shape; Symmetrical three-dimensional structure means that the axis, along the main axis biggest stress of least resistance. Therefore it is asymmetrical shell structure means that the compressor can be greatly reduced along the axis direction of a force while the probability;⑦ set inlet, exhaust muffler, the closed Compressor Muffler generally muffler. It uses Cross Section, resonant cavity caused acoustic impedance changes in reflectivity or sound energy consumption. or use acoustic-acoustic send phase difference of 180 degrees to offset the muffler of noise. Shell compressor in the lateral closed Unicom a Helmholtz resonator, namely : Helmholtz resonator from the chamber through the neck hole and shell compressor connected into the internal cavity, to reduce compressor cavity stimulated acoustic modal amplitude. The results showed : resonator resonance frequency modulation of the actual compressor cavity stimulated the greatest vibration modes, will be substantially reduced resonance peak response spectrum and lead to significant change. However, it will affect the appearance andthe compressor refrigerator settings, the research results are not yet applied to products.Lubricants and residual volume-coil motor windings will lead to the same types of bulk compressor levels between different (from levels average). By changing the shell external support to increase torsional stiffness and reduce vibration surface; Noise study the complex requirements of researchers has strong theory, the enterprise has good skills base and the need for greater investment and a longer timeframe. This is domestic enterprises compressor one of the weak links, which is now basically in the qualitative phase of experimental research, Along with a great chance and randomness.3. new refrigerants ApplicationBased on the new environmental requirements of refrigerant compressor refrigeration industry is a hot issue. As for the refrigerator product R22 refrigerant substitutes the end of the work, new refrigerant compressor in the past few years mainly concentrated in the air conditioning industry. Apart from the now relatively mature R410A, R407C the study, The largest is the hot issue of CO2 compressor. This is the only issue for a briefing.CO2 currently on the research and application of concentrated mainly in three aspects : one is the most urgent need of alternative refrigerants applications, such as automotive air conditioning, as refrigerant emissions, environmental harm, must be adopted as soon as possible without endangering the environment refrigerants; the other is to consider the characteristics of CO2 cycle, the most favorable to the use of this cycle of occasions, If heat pump water heater is to supercritical CO2 in hot conditions decentralization there is a significant temperature slip will help heat Water heated to a higher temperature characteristics of the focus of public attention; another one is CO2 into account the nature of heat transfer properties and characteristics of using CO2 as a refrigerant, taking into account CO2 good cold flow properties andheat transfer characteristics, use it as a cascade refrigeration cycle cryogenic stage refrigerants.Compressor transcritical carbon dioxide as an air conditioning system efficiency and reliability of the most affected parts, It should be fully integrated supercritical carbon dioxide cycle specific characteristics of a new design. Like ammonia and CO2, the adiabatic exponent K value higher, up 1.30, it may result in the compressor discharge temperature high, However, as the needs of CO2 compressor pressure ratio small, there is no need for cooling the compressor itself. Adiabatic index is high pressure over the small, I can reduce the gap compressor further expansion of the volume losses to the higher volume efficiency compressors. After experimental and theoretical research, Jurgen Horst SUB and found Kruse, reciprocating compressor is a good film sliding seal as the preferred CO2 system. 8:3 its carbon dioxide compressor exhaust valve for improved Exhaust improved compressor efficiency of carbon dioxide increased by 7%.As the carbon dioxide pressure is far greater than the traditional critical circulatory pressure, compressor shaft seal design requirements than the original compressor is much higher, compressor shaft seal leakage over a period of time is still hampered Actually, the main reason.Danfoss, Denso, ZEXEL such as carbon dioxide compressor has entered the stage of small batch production.The IEA in March 1999, the Joint Japan, Norway, Sweden, Britain and the United States to activate the "Selected Issue on CO2 as working fluid Compression Systems in the "three-year project.Beginning in 1994, BMW, DAIMLERBENZ VOL O, Germany's Volkswagen and Danfoss. Péchiney and other European companies launched the famous "RACE"to the joint project, the Joint European well-known universities, automotive air conditioning manufacturers and other developed CO2 automotive air-conditioning system. Subregion Motor Company has production equipment CO2 carair-conditioning systems of cars, Germany KONVECTA production to the quality of CO2 in the air-conditioned Buses run from 1996 to date. DANFOSS, the Obrist Austria, the United Kingdom have developed a carbon dioxide compressor motor. Japan DENSO, ZEXEL CO2 compressor has entered the stage of mass production.With major manufacturers inputs, the type of CO2 compressor with ordinary motor compressor trend line major swing to determine the displacement swashplate, scroll and the main variable displacement.4. New principle of refrigeration compressorsIn recent years, the new structure and working principle of refrigeration compressor made a more progress, mainly linear compressor, Elliptic compressors, compressor rotor Swing, spiral vane compressor, in the past, the author has been described in the article, here will not repeat it.Linear compressor which is the domestic refrigerator compressor industry the focus of attention. In 2004 the International Compressor Engineering Conference has five linear compressor on the article. LG and researchers still Sunpower two main companies. The past two years, several domestic enterprises in the refrigerator compressor to the development of the linear compressor, However, enterprises have the technical foundation for the domestic financial strength and the limitations of scientific research institutions, believe in a short period of time can not enter the stage of industrialization.5 the classification of the refrigeration compressor5.1 reciprocating compressorReciprocating compressor is a kind of traditional refrigeration compressor, the biggest characteristic is to achieve the capacity and pressure than any of the design. Although it is widely applied, but the market share is gradually reduced.So far, the fridge (including small freezing and cold storage device) host compound compressor is ever to give priority to. Through the optimal design of valve structure, friction pair, reciprocating refrigerator compressor refrigeration coefficient of power refrigerating capacity (units) by 1.0 (w/w) of the early ninety s to today's 1.8 or so; In addition to the energy saving technology progress, and environmental protection is closely related to the refrigerant alternative technology has also made gratifying progress, refrigerator system in our country has a large number of using R600 hydrocarbons, such as small refrigeration device is also used the new working substance such as everything. To further improve the efficiency of the reciprocating compressor refrigerator, to reduce the system noise is still the development direction of it.5.2 linear compressorStill make reciprocating linear compressor, due to the linear motion of the motor can be directly drives the piston reciprocating motion, so as to avoid the complexity of the crank connecting rod mechanism and the resulting mechanical power consumption. Linear compressor assembly as the refrigerator system has appeared, the refrigeration coefficient of linear refrigerator compressor has more than 2.0 (w/w), market prospects look good. The main problem is the design of the compressor oil system and the effective control of linear motor displacement limit point and the corresponding anti-collision cylinder technology.5.3 the swash plate compressorSwash plate compressor is also a kind of variant structure of reciprocating compressor, is mainly used in automotive air conditioning system at present. After decades of development, the swash plate compressor has become a very mature model, in possession of more than 70 of the automotive air conditioning compressor market. In spite of this, because it still belongs to the series of reciprocating structure, so in thecar air conditioning system can effect comparing (refrigeration coefficient) and only around 1.5, weight and volume is big, big. Because of the mature of swashplate automobile air conditioning compressor technology, combined with technology, further improvement in the foreseeable future, will continue to maintain a certain market share, but in a certain displacement range by substituting is inevitable.5.4 rotor compressorRotor compressor in the 1970 s by the attention of domestic, it represents the structure including the rolling piston type, sliding-vane, etc. On the rolling piston type is widely used in household air conditioner at present, there are also some applications on the refrigerator. This kind of compressor don't need air suction valve, make it suitable for variable speed operation, which can improve system performance by frequency conversion control. In order to ensure high power (3 p) of the motor output power in the performance of the rolling piston compressor, the domestic research and development and the end of last century, double rotor rolling piston compressor, is now on the market. Double rotor on the rolling piston compressor structure has two advantages: (1) force of the rotating system be improved, the machine vibration and noise is reduced; (2) increase the standalone swept volume and improve the output power of the motor.Below 3 p air conditioning unit, temporarily can not replace a good model of the rolling piston compressor. So improve the efficiency of the compression process, reduce noise and motor speed control and the R410A and other related technical issues after new refrigerating agent, etc., is a research direction of the rolling piston compressor.Sliding vane compressor is a kind of rotor compressor, mainly used to provide compressed air, displacement is in commonly 0.3-3 m3 / min, the market share is low. Rotary vane compressor sliding vane compressor is a kind of transition structure, because of its better starting performance, the compression process torque change is not big, at present is mainly used for miniature cars and some smaller displacementplumbing vehicle air conditioning system. The dynamic characteristics under high speed is the main technology of this compressor research direction.5.5 screw compressorScrew compressor with small size, light weight, easy to maintenance etc., is a model of the fast development in refrigeration compressor. On the one hand, the screw type line, structural design has made considerable progress, on the other hand, the introduction of special screw rotor milling especially grinding, improve the machining precision and machining efficiency of key parts, makes the performance of screw compressor has been effectively improved, industrialization production of the necessary hardware also has the safeguard. At present, the screw compressor is given priority to with compressed air, in medium ReBengShi air conditioning has successful application in the system. Due to increasing the reliability of the screw compressor work within the scope of the medium refrigerating capacity has gradually replace of reciprocating compressor and occupied most of the centrifugal compressor market. 5.6 scroll compressorScroll compressor has been rapid development in the past ten years, the structure of the basic theory, research and development to achieve large-scale industrial production, industrial prototype constitutes the compressor technology development new luminescent spot. The development of numerical control processing technology to realize the mass production, the vortex compressor incomparable performance advantage is the precondition of its vast in the market. A few short years, has been in the field of cabinet air conditioning holds an absolute advantage. In cabinet air conditioning system, scroll compressor refrigeration coefficient has amounted to 3.4 (w/w); In the field of automotive air conditioning, the refrigeration coefficient of scroll compressor has amounted to 2.0 (w/w), and shows strong competition potential. The development of the vortex compressor is to enlarge its range of refrigerating capacity, further improve the efficiency, using alternative working medium and lower the manufacturing cost, etc.Since there is no valve, compression force and torque and small changes in the structure make it more suitable for the advantages of frequency control of motor speed operation, it also become the main direction of scroll compressor technology development. Development of scroll compressor of variable displacement mechanism is the key point of the development of the technology. At present, the use of axial sealing technology, "flexible" theory can realize cooling/heating capacity of 10% to 100% within the scope of the regulation.Due to the vortex compressor suction exhaust characteristic of almost continuous, low starting torque and liquid impact resistance, created the condition for parallel use of vortex compressor. In parallel with the vortex compressor can greatly increase the cooling capacity of the unit, can increase from the current single 25 horsepower to single unit 100 horsepower (4 sets of single parallel), and makes the cold quantity adjustment is more reasonable, give full play to the single machine with the highest efficiency. But single in parallel, one of the biggest problems is the oil return is not the average of the unit when using single machine burning phenomenon.3.1.5 centrifugal compressorAt present in large quantity of cold (greater than 1500 kw) remain within the scope of advantage, this is mainly benefited from the cold quantity range, it has incomparable system overall efficiency. The movement of the centrifugal compressor parts little and simple, and its manufacturing precision is much lower than the screw compressor, these are the characteristics of the manufacturing cost is relatively low, and reliable. Relatively speaking, the development of centrifugal compressor is slow, due to the challenges of the screw compressor and absorption chiller. Centrifuge market capacity is around 700 ~ between 1200, because under the premise that the current technology, the machine is mainly used for air conditioning of large buildings, demand is limited. In recent years because of the large infrastructure projects are built, the centrifugal refrigeration and air conditioning compressor is becoming a hot spot of attention again. Solve surge phenomenon, improve the volume adjustment and theadaptability to change with working condition, miniaturization technology is the main development direction of the centrifugal compressor technology.3.1.6 other structure formsSingle tooth of the compressor, some structures, such as cross slider compressor unique positive displacement compressor also has a certain degree of development, but has not been formed in the domestic production capacity.5. Special refrigeration compressorsAlthough domestic enterprises household refrigeration compressors long accustomed to large-scale production mode, we are accustomed to the number of effectiveness. However, the fierce price competition situation, as products become increasingly lower profit margins, When the production of millions of compressors can only make a few million dollars of profit, some on special refrigeration compressors can be regarded as a way out. Special refrigeration compressor exhaustive, it is impossible in this enumeration. But their common feature is their production scale is small, a single high-profit products faster transition, In most cases the need for the user's requirements designed. These products lead to more and more domestic enterprises to the compressor. If the number of domestic enterprises are developing or already have production capacity of the refrigerator compressor truck翻译小型制冷压缩机研究压缩机是制冷系统的核心和心脏，它决定了制冷系统的能力和特征。
机械毕业设计英文外文翻译484往复式发动机
外文翻译外文翻译原文：The Reciprocating EngineMy Internet research eventually led me to the American Stirling Company．While cruising their website for engine kits I ran across，an ad that said they wanted a technical writer who would trade some writing of instructional material and plans for engine kits．I shot them a quick email．I am a technical writer in my day job，and I write instructional material for computer software．Now that I was designing my own Stirling engines，I thought I would be a perfect match for them!Well，I didn’t end up working for them，but after afew conversations with the owner of the company I was on a mission to complete my quest for a hand built LTD Stirling engine，and I was going to write a book about it at the same time．Brent Van Arsdell of The American Stirling Company was very helpful．He gave me some very good advice about how to increase the efficiency of my engine designs．He knew a lot a bout friction．He knew how to calculate its impact，and how to overcome some of the problems it can cause．He didn’t really need a technical writer any more，but he did offer me some great encouragement on my efforts to design an efficient hand built engine．He suggested that if I could build a Stirling engine that met these criteria，it would make a great sellingbook．Here is what my designs had to do：·The engine had to run from the heat of a warm hand．·The engine had to be made from common materials that would be easy for anyone to obtain．·It had to be affordable to build．·It had to be built without the aid of a machine shop．I could only use the kinds of tools that most folks already have in their garage．I stumbled across the website of an engineer in France who was working on a similar project．The only problem was the website was entirely in French!I had a brief email exchange with the author and asked him if his website was available i n English．He replied。
外文翻译--热力学分析的往复式压缩机
附件1：外文资料翻译译文往复式压缩机的热力学分析Pascal Stouffs a*, Mohand Tazerout b, Pierre Wauters ca ISITEM, La Chantrerie, BP 90604, 44306 Nantes cedex 3, Franceb École des Mines de Nantes, 4, rue Alfred-Kastler, BP 20722, 44307 Nantes cedex 3, Francec Université Catholique de Louvain, Unité TERM, place du Levant, 2, 1348 Louvain-la-Neuve,Belgique摘要一种往复式压缩机的热力学分析总体模型。
该模型是由5个主要和4个次要的无量纲物理参数构成。
容积效率表达式，由单位工作质量和效率导出。
此模型用以预测不同工况条件下的往复式空气压缩机的性能。
实验表明，该模型是分析压缩机性能时非常准确和有用的工具。
文章探讨了各项损失的相对重要性及不同工作参数对往复式压缩机的影响。
特别是缸内残留气体质量和壁对流体传热对往复式压缩机性能的影响尤为明显。
关键词往复式压缩机热力学分析气到壁传热容积效率实验结果文章参数Cp 定压比热容. . . ……………J/kg·K f 形状因子的方程(32)h 焓. . . . . . . . . . . . ………….. J/kgm 气体质量. . . . . . . . . . . . . . . . kgp 压力. . . . . . . . . . . . . . . . . .. Paq 单位质量的热. . . . . . . . . . .J/kgs 比熵. . . . . . . . . . . . . ………. J/kg·K T 温度. . . . . . . . . . . . . . . ….... KTm 平均温度. . . . . . . . . . . . …..KV 体积. . . . . . . . . . . . . . . . . . m³v 单位质量的体积 . . . . . . . . . .m³/kg W 功率. . . . . . . . . . . . . . . . . . . .. Jw 比功率. . . . . . . . . . . . . . …... J/kg希腊符号α2 热传导系数(12)α3 热传导系数(13)βdis压力系数(3) βsuc压力系数(2)γ熵参数εc因数εv容积系数ζf 工作参数(35)ζ1温度参数(9)η效率ϑ2=T2/T2;s ,温度比Θs=T2,s/T1 熵压缩温度比κ平均热容比(42)ξw温度参数(10)ξ1温度参数(9)Π= p2/p1, 缸内压力比Πdis=pdis/psuc, 压力比ϕ无量纲常数(37)χ无量纲常数(39)ψ无量纲常数(40)下标A 在压缩过程中该气反转点壁热通量B 在扩大该气反转点壁热通量C 气缸c 清除dis 释放f 摩擦，不可逆转ind 表示m 机械s 熵suc 吸力w 壁1 死点在气缸内的状态下时2 在气缸内开始释放时状态3 在汽缸内上止点的状态4 在汽缸内开始在吸的状态*（上标）参考值（灵敏度分析）1. 引言往复式压缩机，广泛应用于很多工程应用。
螺杆式压缩机的设计外文文献翻译、中英文翻译、外文翻译
英文原文1 IntroductionThe screw compressor is one of the most common types of machine used to compress gases. Its construction is simple in that it essentially comprises only a pair of meshing rotors, with helical grooves machined in them, contained in a casing, which fits closely round them. The rotors and casing are separated by very small clearances. The rotors are driven by an external motor and mesh like gears in such a manner that, as they rotate, the space formed between them and the casing is reduced progressively. Thus, any gas trapped in this case is compressed. The geometry of such machines is complex and the flow of the gas being compressed within them occurs in three stages. Firstly, gas enters between the lobes, through an inlet port at one end of the casing during the start of rotation. As rotation continues, the space between the rotors no longer lines up with the inlet port and the gas is trapped and thus compressed. Finally, after further rotation, the opposite ends of the rotors pass a second port at the other end of the casing, through which the gas is discharged. The whole process is repeated between successive pairs of lobes to create a continuous but pulsating flow of gas from low to high pressure.These machines are mainly used for the supply of compressed air in the building industry, the food, process and pharmaceutical industries and, where required, in the metallurgical industry and for pneumatic transport.They are also used extensively for compression of refrigerants in refrigeration and air conditioning systems and of hydrocarbon gases in the chemical industry. Their relatively rapid acceptance over the past thirty years is due to their relatively high rotational speeds compared to other types of positive displacement machine, which makes them compact, their ability to maintain high efficiencies over a wide range of operating pressures and flow rates and their long service life and high reliability. Consequently, they constitute a substantial percentage of all positive displacement compressors now sold and currently in operation.The main reasons for this success are the development of novel rotor profiles, which have drastically reduced internal leakage, and advanced machine tools, which can manufacture the most complex shapes to tolerances of the order of 3 micrometers at an acceptable cost. Rotor profile enhancement is still the most promising means of further improving screw compressors and rational procedures are now being developed both to replace earlier empirically derived shapes and also to vary the proportions of the selected profile to obtain the best result for the application for which the compressor is required. Despite their wide usage, due to the complexity of their internal geometry and the non-steady nature of the processes within them, up till recently, only approximate analytical methods have been available to predict their performance. Thus, although it is known that their elements are distorted both by the heavy loads imposed by pressure induced forces and through temperature changes within them, no methods were available to predict the magnitude of these distortions accurately, nor how they affect the overall performance of the machine. In addition, improved modelling of flow patterns within the machine can lead to better porting design. Also, more accurate determination of bearing loads and how they fluctuate enable better choices of bearings to be made. Finally, if rotor and casing distortion, as a result of temperature and pressure changes within the compressor, can be estimated reliably, machining procedures can be devised to minimise their adverse effects.Screw machines operate on a variety of working fluids, which may be gases, dry vapour or multi-phase mixtures with phase changes taking place within the machine. They may involve oil flooding, or other fluids injected during the compression or expansion process, or be without any form of internal lubrication. Their geometry may vary depending on the number of lobes in each rotor, the basic rotor profile and the relative proportions of each rotor lobe segment. It follows that there is no universal configuration which would be the best for all applications. Hence, detailed thermodynamic analysis of the compression process and evaluation of the influence of the various design parameters on performance is more important to obtain the best results from these machines than from other types which could be used for the same application. A set of well defined criteria governed by an optimisation procedure is therefore a prerequisite for achieving the best design for each application. Such guidelines are also essential for the further improvement of existing screw machine designs and broadening their range of uses. Fleming et al., 1998 gives a good contemporary review of screw compressor modelling, design and application.A mathematical model of the thermodynamic and fluid flow processes within positive displacement machines, which is valid for both the screw compressor and expander modes of operation, is presented in this Monograph. It includes the use of the equations of conservation of mass, momentum and energy applied to an instantaneous control volume of trapped fluid within the machine with allowance for fluid leakage, oil or other fluid injection, heat transfer and the assumption of real fluid properties. By simultaneous solution of these equations, pressure-volume diagrams may be derived of the entire admission, discharge and compression or expansion process within the machine. A screw machine is defined by the rotor profile which is here generated by use of a general gearing algorithm and the port shape and size. This algorithm demonstrates the meshing condition which, when solved explicitly,enables a variety of rotor primary arcs to be defined either analytically or by discrete point curves. Its use greatly simplifies the design since only primary arcs need to be specified and these can be located on either the main or gate rotor or even on any other rotor including a rack, which is a rotor of infinite radius. The most efficient profiles have been obtained from a combined rotor-rack generation procedure.The rotor profile generation processor, thermofluid solver and optimizer,together with pre-processing facilities for the input data and graphical post processing and CAD interface, have been incorporated into a design tool in the form of a general computer code which provides a suitable tool for analysis and optimization of the lobe profiles and other geometrical and physical parameters. The Monograph outlines the adopted rationale and method of modelling, compares the shapes of the new and conventional profiles and illustrates potential improvements achieved with the new design when applied to dry and oil-flooded air compressors as well as to refrigeration screw compressors.The first part of the Monograph gives a review of recent developments in screw compressors.The second part presents the method of mathematical definition of the general case of screw machine rotors and describes the details of lobe shape specification. It focuses on a new lobe profile of a slender shape with thinner lobes in the main rotor, which yields a larger cross-sectional area and shorter sealing lines resulting in higher delivery rates for the same tip speed.The third part describes a model of the thermodynamics of the compression-expansion processes, discusses some modelling issues and compares the shapes of new and conventional profiles. It illustrates the potentialimprovements achievable with the new design applied to dry and oil-flooded air compressors as well as to refrigeration screw compressors. The selection of the best gate rotor tip radius is given as an example of how mathematical modelling may be used to optimise the design and the machine’s operating conditions.The fourth part describes the design of a high efficiency screw compressor with new rotor profiles. A well proven mathematical model of the compression process within positive displacement machines was used to determine the optimum rotor size and speed, the volume ratio and the oil injection position and jet diameter. In addition, modern design concepts such as an open suction port and early exposure of the discharge port were included, together with improved bearing and seal specification, to maximise the compressor efficiency. The prototypes were tested and compared with the best compressors currently on the market. The measured specific power input appeared to be lower than any published values for other equivalent compressors currently manufactured. Both the predicted advantages of the new rotor profile and the superiority of the design procedure were thereby confirmed.1.1 Basic ConceptsThermodynamic machines for the compression and expansion of gases and vapours are the key components of the vast majority of power generation and refrigeration systems and essential for the production of compressed air and gases needed by industry. Such machines can be broadly classified by their mode of operation as either turbomachines or those of the positive displacement type.Turbomachines effect pressure changes mainly by dynamic effects, related to the change of momentum imparted to the fluids passing through them. These are associated with the steady flow of fluids at high velocities and hence these machines are compact and best suited for relatively large mass flow rates. Thus compressors and turbines of this type are mainly used in the power generation industry, where, as a result of huge investment in research and development programmes, they are designed and built to attain thermodynamic efficiencies of more than 90% in large scale power production plant. However, the production rate of machines of this type is relatively small and worldwide, is only of the order of some tens of thousands of units per annum.Positive displacement machines effect pressure changes by admitting a fixed mass of fluid into a working chamber where it is confined and then compressed or expanded and, from which it is finally discharged. Such machines must operate more or less intermittently. Such intermittent operation is relatively slow and hence these machines are comparatively large. They are therefore better suited for smaller mass flow rates and power inputs and outputs. A number of types of machine operate on this principle such as reciprocating, vane, scroll and rotary piston machines.In general, positive displacement machines have a wide range of application, particularly in the fields of refrigeration and compressed air production and their total world production rate is in excess of 200 million units per annum. Paradoxically, but possibly because these machines are produced by comparatively small companies with limited resources, relatively little is spent on research and development programmes on them and there are very few academic institutions in the world which are actively promoting their improvement.One of the most successful positive displacement machines currently in use is the screw or twin screw compressor. Its principle of operation, as indicated in Fig. 1.1, is based on volumetric changes in three dimensions rather than two. As shown, it consists, essentially, of a pair of meshing helical lobed rotors, contained in a casing.The spaces formed between the lobes on each rotor form a series of working chambers in which gas or vapour is contained. Beginning at the top and in front of the rotors, shown in the light shaded portion of Fig. 1.1a, there is a starting point for each chamber where the trapped volume is initially zero. As rotation proceeds in the direction of the arrows, the volume of that chamber then increases as the line of contact between the rotor with convex lobes, known as the main rotor, and the adjacent lobe of the gate rotorFig. 1.1. Screw Compressor Rotorsadvances along the axis of the rotors towards the rear. On completion of one revolution i.e. 360◦by the main rotor, the volume of the chamber is then a maximum and extends in helical form along virtually the entire length of the rotor. Further rotation then leads to reengagement of the main lobe with the succeeding gate lobe by a line of contact starting at the bottom and front of the rotors and advancing to the rear, as shown in the dark shaded portions in Fig. 1.1b. Thus, the trapped volume starts to decrease. On completion of a further 360◦of rotation by the main rotor, the trapped volume returns to zero.The dark shaded portions in Fig. 1.1 show the enclosed region where therotors are surrounded by the casing, which fits closely round them, while the light shaded areas show the regions of the rotors, which are exposed to external pressure. Thus the large light shaded area in Fig. 1.1a corresponds to the low pressure port while the small light shaded region between shaft ends B and D in Fig. 1.1b corresponds to the high pressure port.Exposure of the space between the rotor lobes to the suction port, as their front ends pass across it, allows the gas to fill the passages formed between them and the casing until the trapped volume is a maximum. Further rotation then leads to cut off of the chamber from the port and progressive reduction in the trapped volume. This leads to axial and bending forces on the rotors and also to contact forces between the rotor lobes. The compression process continues until the required pressure is reached when the rear ends of the passages are exposed to the discharge port through which the gas flows out at approximately constant pressure. It can be appreciated from examination of Fig. 1.1, is that if the direction of rotation of the rotors is reversed, then gas will flow into the machine through the high pressure port and out through the low pressure port and it will act as an expander. The machine will also work as an expander when rotating in the same direction as a compressor provided that the suction and discharge ports are positioned on the opposite sides of the casing to those shown since this iseffectively the same as reversing the direction of rotation relative to the ports. When operating as a compressor, mechanical power must be supplied to shaft A to rotate the machine. When acting as an expander, it will rotate automatically and power generated within it will be supplied externally through shaft A.The meshing action of the lobes, as they rotate, is the same as that of helical gears but, in addition, their shape must be such that at any contact position, a sealing line is formed between the rotors and between the rotors and the casing in order to prevent internal leakage between successive trapped passages. A further requirement is that the passages between the lobes should be as large as possible, in order to maximise the fluid displacement per revolution. Also, the contact forces between the rotors should be low in order to minimise internal friction losses.A typical screw rotor profile is shown in Fig. 1.2, where a configuration of 5–6 lobes on the main and gate rotors is presented. The meshing rotors are shown with their sealing lines, for the axial plane on the left and for the cross-sectional plane in the centre. Also, the clearance distribution between the two rotor racks in the transverse plane, scaled 50 times (6) is given above.Fig. 1.2. Screw rotor profile: (1) main, (2) gate, (3) rotor external and (4) pitch circles, (5) sealing line, (6) clearance distribution and (7) rotor flow area between the rotors and housingOil injected Oil FreeFig. 1.3. Oil Injected and Oil Free CompressorsScrew machines have a number of advantages over other positive displacement types. Firstly, unlike reciprocating machines, the moving parts all rotate and hence can run at much higher speeds. Secondly, unlike vane machines, the contact forces within them are low, which makes them very reliable. Thirdly, and far less well appreciated, unlike the reciprocating, scroll and vane machines, all the sealing lines of contact which define the boundaries of each cell chamber, decrease in length as the size of the working chamber decreases and the pressure within it rises. This minimises the escape of gas from the chamber due to leakage during the compression or expansion process.1.2 Types of Screw CompressorsScrew compressors may be broadly classified into two types. These are shown in Fig. 1.3 where machines with the same size rotors are compared:1.2.1 The Oil Injected MachineThis relies on relatively large masses of oil injected with the compressed gas in order to lubricate the rotor motion, seal the gaps and reduce the temperature rise during compression. It requires no internal seals, is simple in mechanical design, cheap to manufacture and highly efficient. Consequently it is widely used as a compressor in both the compressed air and refrigeration industries.1.2.2 The Oil Free MachineHere, there is no mixing of the working fluid with oil and contact between the rotors is prevented by timing gears which mesh outside the working chamber and are lubricated externally. In addition, to prevent lubricant entering the working chamber, internal seals are required on each shaft between the working chamber and the bearings. In the case of process gas compressors, double mechanical seals are used. Even with elaborate and costly systems such as these, successful internal sealing is still regarded as a problem by established process gas compressor manufacturers. It follows that such machines are considerably more expensive to manufacture than those that are oil injected.Both types require an external heat exchanger to cool the lubricating oil before it is readmitted to the compressor. The oil free machine requires an oil tank, filters and a pump to return the oil to the bearings and timing gear.The oil injected machine requires a separator to remove the oil from the high pressure discharged gas but relies on the pressure difference between suction and discharge to return the separated oil to the compressor. Theseadditional components increase the total cost of both types of machine but the add on cost is greater for the oil free compressor.1.3 Screw Machine DesignSerious efforts to develop screw machines began in the nineteen thirties, when turbomachines were relatively inefficient. At that time, Alf Lysholm, a talented Swedish engineer, required a high speed compressor, which could be coupled directly to a turbine to form a compact prime mover, in which the motion of all moving parts was purely rotational. The screw compressor appeared to him to be the most promising device for this purpose and all modern developments in these machines stem from his pioneering work. Typical screw compressor designs are presented in Figs. 1.4 and 1.5. From then until the mid nineteen sixties, the main drawback to their widespread use was the inability to manufacture rotors accurately at an acceptable cost. Two developments then accelerated their adoption. The first was the development of milling machines for thread cutting. Their use for rotor manufacture enabled these components to be made far more accurately at an acceptable cost. The second occurred in nineteen seventy three, when SRM, in Sweden, introduced the “A” profile, which reduced the internal leakage path area, known as the blow hole, by 90%. Screw compressors could then be built with efficiencies approximately equal to those of reciprocating machines and, in their oil flooded form, could operate efficiently with stage pressure ratios of up to 8:1. This was unattainable with reciprocating machines. The use of screw compressors, especially of the oil flooded type, then proliferated.Fig. 1.4. Screw compressor mechanical partsFig. 1.5. Cross section of a screw compressor with gear boxTo perform effectively, screw compressor rotors must meet the meshing requirements of gears while maintaining a seal along their length to minimise leakage at any position on the band of rotor contact. It follows that the compressor efficiency depends on both the rotor profile and the clearances between the rotors and between the rotors and the compressor housing.Screw compressor rotors are usually manufactured on pecialized machines by the use of formed milling or grinding tools. Machining accuracy achievable today is high and tolerances in rotor manufacture are of the order of 5 μm around the rotor lobes. Holmes, 1999 reported that even higher accuracy was achieved on the new Holroyd vitrifying thread-grinding machine, thus keeping the manufacturing tolerances within 3 μm even in large batch production. This means that, as far as rotor production alone is concerned, clearances betweenthe rotors canbe as small as 12 μm.中文译文1 引言螺杆式压缩机是一种最常见的用来压缩气体的机器。
文献翻译-离心风机
Centrifugal fanA centrifugal fan (also squirrel-cage fan, as it looks like a hamster wheel) is a mechanical device for moving air or gases. It has a fan wheel composed of a number of fan blades, or ribs, mounted around a hub. As shown in Figure 1, the hub turns on a driveshaft that passes through the fan housing. The gas enters from the side of the fan wheel, turns 90 degrees and accelerates due to centrifugal force as it flows over the fan blades and exits the fan housing.[1]Figure 1Centrifugal fans can generate pressure rises in the gas stream. Accordingly, they are well-suited for industrial processes and air pollution control systems. They are also common in central heating/cooling systems.1. Fan componentsThe major components of a typical centrifugal fan include the fan wheel, fan housing, drive mechanism, and inlet and/or outlet dampers.2. Types of drive mechanismsThe fan drive determines the speed of the fan wheel (impeller) and the extent to which this speed can be varied. There are three basic types of fan drives.[1]2.1Direct driveThe fan wheel can be linked directly to the shaft of an electric motor. This means that the fan wheel speed is identical to the motor's rotational speed. With this type of fan drive mechanism, the fan speed cannot be varied unless the motor speed is adjustable.2.2.1 Belt driveFigure 2: Centrifugal fan with a belt driveBelt driven fans use multiple belts that rotate in a set of sheaves mounted on the motor shaft and the fan wheel shaft.This type of drive mechanism is depicted in figure 2. The belts transmit the mechanical energy from the motor to the fan.The fan wheel speed depends upon the ratio of the diameter of the motor sheave to the diameter of the fan wheel sheave and can be obtained from this equation:[1]where:rpm fan= fan wheel speed, revolutions per minuterpm motor= motor nameplate speed, revolutions per minuteD motor= diameter of the motor sheaveD fan= diameter of the fan wheel sheaveFan wheel speeds in belt-driven fans are fixed unless the belts slip. Belt slippage can reduce the fan wheel speed several hundred revolutions per minute (rpm).2.2Variable driveVariable drive fans use hydraulic or magnetic couplings (between the fan wheel shaft and the motor shaft) that allow control of the fan wheel speed independent of the motor speed. The fan speed controls are often integrated into automated systems to maintain the desired fan wheel speed.[1]An alternate method of varying the fan speed is by use of an electronic variable-speed drive which controls the speed of the motor driving the fan. This offers better overall energy efficiency at reduced speeds than mechanical couplings.2.3 Fan dampersFan dampers are used to control gas flow into and out of the centrifugal fan. They may be installed on the inlet side or on the outlet side of the fan, or both. Dampers on the outlet side impose a flow resistance that is used to control gas flow. Dampers on the inlet side are designed to control gas flow and to change how the gas enters the fan wheel.Inlet dampers reduce fan energy usage due to their ability to affect the airflow pattern into the fan.[1]3. Backward-curved bladesBackward-curved blades, as in Figure 3(b), use blades that curve against the direction of the fan wheel's rotation. The backward curvature mimics that of an airfoil cross section and provides good operating efficiency with relatively economical construction techniques. These types of fan wheels are used in fans designed to handle gas streams with low to moderate particulate loadings. They can be easily fitted with wear protection but certain blade curvatures can be prone to solids build-up.Backward curved fans can have a high range of specific speeds but are most often used for medium specific speed applications-- high pressure, medium flow applications.Backward-curved fans are much more energy efficient than radial blade fans and so, for high horsepower applications may be a suitable alternative to the lower cost radial bladed fan.4. Straight radial bladesRadial fan blades, as in Figure 3(c), extend straight out from the hub. A radial blade fan wheel is often used on particulate-laden gas streams because it is the least sensitive to solids build-up on the blades, but it is often characterized by greater noise output. High speeds, low volumes, and high pressures are common with radial fans, and are often used in vacuum cleaners, pneumatic material conveying systems, and similar processes.Figure 35. Centrifugal fan ratingsRatings found in centrifugal fan performance tables and curves are based on standard air SCFM. Fan manufacturers define standard air as clean, dry air with a density of 0.075 pounds mass per cubic foot (1.2kg/m³), with the barometric pressure at sea level of 29.92 inches of mercury (101.325kPa) and a temperature of 70°F (21°C). Selecting a centrifugal fan to operate at conditions other than standard air requires adjustment to both static pressure and brake horsepower. The volume of air will not be affected in a given system because a fan will move the same amount of air regardless of the air density.If a centrifugal fan is to operate at a non-standard density, then corrections must be made to static pressure and brake horsepower. At higher than standard elevation (sea level) and higher than standard temperature, air density is lower than standard density. Centrifugal fans that are specified for continuous operation at higher temperatures need to be selected taking into account air density corrections. Again, a centrifugal fan is a constant volume device that will move the same amount of air at two different temperatures.If, for example, a centrifugal fan moves 1,000 ft³/min (28 m³/min) at 70 °F (21 °C) it will also move 1,000 ft³/min (28 m³/min) at 200 °F (93 °C). Centrifugal fan air volume delivered by the centrifugal fan is not affected by density. However, since the 200 °F (93 °C) air weighs much less than the 70 °F (21 °C) air, the centrifugal fan will create less static pressure and will require less brake horsepower. Selecting a centrifugal fan to operate at conditions other than standard air requires adjustment to both static pressure and power. When a centrifugal fan is specified for a given CFM and static pressure at conditions other than standard, an air density correction factor must be applied to select the proper size fan to meet the new condition. Since 200 °F (93 °C) air weighs only 80% of 70 °F (21 °C) air, the centrifugal fan will create less pressure. To get the actual pressure required at 200 °F (93 °C), the designer would have to multiply the pressure at standard conditions by an air density correction factor of 1.25 (i.e., 1.0 / 0.8) to get the system to operate correctly. To get the actual power at 200 °F (93 °C), the designer would have to divide the power at standard conditions by the air density correction factor.离心风机离心风机（也鼠笼式风扇，因为它看起来像仓鼠轮）是一种机械装置移动空气或气体。
空气压缩机论文中英文对照资料外文翻译文献
毕业设计外文资料翻译附件1：外文资料翻译译文一维多级轴流压缩机性能的解析优化摘要 对多级压缩机的优化设计模型，本文假设固定的流道形状以入口和出口的动叶绝对角度，静叶的绝对角度和静叶及每一级的入口和出口的相对气体密度作为设计变量，得到压缩机基元级的基本方程和多级压缩机的解析关系。
用数值实例来说明多级压缩机的各种参数对最优性能的影响。
关键词 轴流压缩机 效率 分析关系 优化1 引言轴流式压缩机的设计是工艺技术的一部分，如果缺乏准确的预测将影响设计过程。
至今还没有公认的方法可使新的设计参数达到一个足够精确的值，通过应用一些已经取得新进展的数值优化技术，以完成单级和多级轴流式压缩机的设计。
计算流体动力学（CFD ）和许多更准确的方法特别是发展计算的CFD 技术，已经应用到许多轴流式压缩机的平面和三维优化设计。
它仍然是使用一维流体力学理论用数值实例来计算压缩机的最佳设计。
Boiko 通过以下假设提出了详细的数学模型用以优化设计单级和多级轴流涡轮：（1）固定的轴向均匀速度分布（2）固定流动路径的形状分布，并获得了理想的优化结果。
陈林根等人也采用了类似的想法，通过假设一个固定的轴向速度分布的优化设计提出了设计单级轴流式压缩机一种数学模型。
在本文中为优化设计多级轴流压缩机的模型，提出了假设一个固定的流道形状，以入口和出口的动叶绝对角度，静叶的绝对角度和静叶及每一级的入口和出口的相对气体密度作为设计变量，分析压缩机的每个阶段之间的关系，用数值实例来说明多级压缩机的各种参数对最优性能的影响。
2 基元级的基本方程考虑图1所示由n 级组成的轴流压缩机, 其某一压缩过程焓熵图和中间级的速度三角形见图2和图3，相应的中间级的具体焓熵图如图4，按一维理论作级的性能计算。
按一般情况列出轴流压缩机中气体流动的能量方程和连续方程,工作流体和叶轮的速度。
在不同级的轴向流速不为常数，即考虑i j u u ≠,i j c c ≠ (i j ≠) 时的能量和流量方程。
往复式和离心式压缩机论文中英文对照资料外文翻译文献
中英文对照资料外文翻译文献离心式和往复式压缩机的工作效率特性往复式压缩机和离心式压缩机具有不同的工作特性，而且关于效率的定义也不同。
本文提供了一个公平的比较准则，得到了对于两种类型机器普遍适用的效率定义。
这个比较基于用户最感兴趣的要求提出的。
此外，对于管道的工作环境影响和在不同负载水平的影响给出了评估。
乍一看，计算任何类型的压缩效率看似是很简单的：比较理想压缩过程和实际压缩过程的工作效率。
难点在于正确定义适当的系统边界，包括与之相关的压缩过程的损失。
除非这些边界是恰好定义的，否则离心式和往复式压缩机的比较就变得有缺陷了。
我们也需要承认，效率的定义，甚至是在评估公平的情况下，仍不能完全回应操作员的主要关心问题：压缩过程所需的驱动力量是什么？要做到这一点，就需要讨论在压缩过程中的机械损失。
随着时间的推移效率趋势也应被考虑，如非设计条件，它们是由专业的流水线规定，或者是受压缩机的工作时间和自身退化的影响。
管道使用的压缩设备涉及到往复式和离心式压缩机。
离心式压缩机用燃气轮机或者是电动马达来驱动。
所用的燃气轮机，总的来说，是两轴发动机，电动马达使用的是变速马达或者变速齿轮箱。
往复压缩机是低速整体单位或者是可分的“高速”单位，其中低速整体单位是燃气发动机和压缩机在一个曲柄套管内。
后者单位的运行在750-1,200rpm 范围内（1,800rpm 是更小的单位）并且通常都是由电动马达或者四冲程燃气发动机来驱动。
效率要确定任何压缩过程的等熵效率，就要基于测量的压缩机吸入和排出的总焓(h)，总压力(p)，温度(T)和熵(s)，于是等熵效率s η变为：)],(),([)],(),([suct suct disch disch suct suct suct disch s T p h T p h T p h s p h --=η (Eq.1)并且加上测量的稳态质量流m ，吸收轴功率为：)],(),([.suct suct disch disch m T p h T p h m p -=η (Eq.2)考虑机械效率m η。
压缩机专业词汇中英文对照大全，你不收藏算我输！
压缩机专业词汇中英文对照大全，你不收藏算我输！中英对照压缩机分类及配件词汇容积式压缩机 positive displacement compressor往复式压缩机（活塞式压缩机） reciprocating compressor 回转式压缩机 rotary compressor滑片式压缩机 sliding vane compressor单滑片回转式压缩机 single vane rotary compressor滚动转子式压缩机 rolling rotor compressor三角转子式压缩机 triangle rotor compressor多滑片回转式压缩机 multi-vane rotary compressor滑片 blade旋转活塞式压缩机 rolling piston compressor涡旋式压缩机 scroll compressor涡旋盘 scroll固定涡旋盘 stationary scroll, fixed scroll驱动涡旋盘 driven scroll, orbiting scroll斜盘式压缩机（摇盘式压缩机） swash plate compressor 斜盘 swash plate摇盘 wobble plate螺杆式压缩机 screw compressor单螺杆压缩机 single screw compressor阴转子 female rotor阳转子 male rotor主转子 main rotor闸转子 gate rotor无油压缩机 oil free compressor膜式压缩机 diaphragm compressor活塞式压缩机 reciprocating compressor单作用压缩机 single acting compressor双作用压缩机 double acting compressor双效压缩机 dual effect compressor双缸压缩机 twin cylinder compressor闭式曲轴箱压缩机 closed crankcase compressor开式曲轴箱压缩机 open crankcase compressor顺流式压缩机 uniflow compressor逆流式压缩机 return flow compressor干活塞式压缩机 dry piston compressor双级压缩机 compound compressor多级压缩机 multistage compressor差动活塞式压缩机stepped piston compound compressor, differential piston compressor串轴式压缩机 tandem compressor, dual compressor截止阀 line valve, stop valve排气截止阀 discharge line valve吸气截止阀 suction line valve部分负荷旁通口 partial duty port能量调节器 energy regulator容量控制滑阀 capacity control slide valve容量控制器 capacity control消声器 muffler联轴节 coupling曲轴箱 crankcase曲轴箱加热器 crankcase heater轴封 crankcase seal, shaft seal填料盒 stuffing box轴封填料 shaft packing机械密封 mechanical seal波纹管密封 bellows seal转动密封 rotary seal迷宫密封 labyrinth seal轴承 bearing滑动轴承 sleeve bearing偏心环 eccentric strap滚珠轴承 ball bearing滚柱轴承 roller bearing滚针轴承 needle bearing止推轴承 thrust bearing外轴承 pedestal bearing臼形轴承 footstep bearing轴承箱 bearing housing止推盘 thrust collar偏心销 eccentric pin曲轴平衡块crankshaft counterweight, crankshaft balance weight曲柄轴 crankshaft偏心轴 eccentric type crankshaft曲拐轴 crank throw type crankshaft连杆 connecting rod连杆大头 crank pin end连杆小头 piston pin end曲轴 crankshaft主轴颈 main journal曲柄 crank arm, crank shaft曲柄销 crank pin曲拐 crank throw曲拐机构 crank-toggle阀盘 valve disc阀杆 valve stem阀座 valve seat阀板 valve plate阀盖 valve cage阀罩 valve cover阀升程限制器valve lift guard阀升程 valve lift阀孔 valve port吸气口 suction inlet压缩机气阀 compressor valve吸气阀 suction valve排气阀 delivery valve圆盘阀 disc valve环片阀 ring plate valve簧片阀 reed valve舌状阀 cantilever valve条状阀 beam valve提升阀 poppet valve菌状阀 mushroom valve杯状阀 tulip valve缸径 cylinder bore余隙容积 clearance volume附加余隙（补充余隙） clearance pocket活塞排量 swept volume, piston displacement理论排量 theoretical displacement实际排量 actual displacement实际输气量 actual displacement, actual output of gas气缸工作容积 working volume of the cylinder活塞行程容积 piston displacement气缸 cylinder气缸体 cylinder block气缸壁 cylinder wall水冷套 water cooled jacket气缸盖（气缸头） cylinder head安全盖（假盖） safety head假盖 false head活塞环 piston ring气环 sealing ring刮油环 scraper ring油环 scrape ring活塞销 piston pin活塞 piston活塞行程 piston stroke吸气行程 suction stroke膨胀行程 expansion stroke压缩行程 compression stroke排气行程 discharge stroke升压压缩机 booster compressor立式压缩机 vertical compressor卧式压缩机 horizontal compressor角度式压缩机 angular type compressor对称平衡型压缩机 symmetrically balanced type compressor 压缩机参数词汇1. performance parameter 性能参数——表征压缩机主要性能的诸参数，如：气量、压力、温度、功率及噪声、振动等2. constructional parameter 结构参数——表征压缩机结构特点的诸参数，如：活塞力、行程、转速、列数、各级缸径、外形尺寸等3. inlet pressure/suction pressure 吸气压力（吸入压力）——在标准吸气位置气体的平均绝对全压力。
机械设计制造及其自动化毕业论文中英文资料外文翻译
机械设计创造及其自动化毕业论文外文文献翻译INTEGRATION OF MACHINERY译文题目专业机械设计创造及其自动化外文资料翻译INTEGRATION OF MACHINERY（From ELECTRICAL AND MACHINERY INDUSTRY）ABSTRACTMachinery was the modern science and technology development inevitable result, this article has summarized the integration of machinery technology basic outline and the development background .Summarized the domestic and foreign integration of machinery technology present situation, has analyzed the integration of machinery technology trend of development.Key word： integration of machinery ，technology， present situation ，product t，echnique of manufacture ，trend of development0. Introduction modern science and technology unceasing development, impelled different discipline intersecting enormously with the seepage, has caused the project domain technological revolution and the transformation .In mechanical engineering domain, because the microelectronic technology and the computer technology rapid development and forms to the mechanical industry seepage the integration of machinery, caused the mechanical industry the technical structure, the product organization, the function and the constitution, the production method and the management systemof by machinery for the characteristic integration ofdevelopment phase.1. Integration of machinery outline integration of machinery is refers in the organization new owner function, the power function, in the information processing function and the control function introduces the electronic technology, unifies the system the mechanism and the computerization design and the software which constitutes always to call. The integration of machinery development also has become one to have until now own system new discipline, not only develops along with the science and technology, but also entrusts with the new content .But its basic characteristic may summarize is: The integration of machinery is embarks from the system viewpoint, synthesis community technologies and so on utilization mechanical technology, microelectronic technology, automatic control technology, computer technology, information technology, sensing observation and control technology, electric power electronic technology, connection technology, information conversion technology as well as software programming technology, according to the system function goal and the optimized organization goal, reasonable disposition and the layout various functions unit, in multi-purpose, high grade, redundant reliable, in the low energy consumption significance realize the specific function value, and causes the overall system optimization the systems engineering technology .From this produces functional system, then becomes an integration of machinery systematic or the integration of machinery product. Therefore, of coveringtechnology is based on the above community technology organic fusion one kind of comprehensive technology, but is not mechanical technical, the microelectronic technology as well as other new technical simple combination, pieces together .This is the integration of machinery and the machinery adds the machinery electrification which the electricity forms in the concept basic difference .The mechanical engineering technology has the merely technical to develop the machinery electrification, still was the traditional machinery, its main function still was replaces with the enlargement physical strength .But after develops the integration of machinery, micro electron installment besides may substitute for certain mechanical parts the original function, but also can entrust with many new functions,like the automatic detection, the automatic reduction information, demonstrate the record, the automatic control and the control automatic diagnosis and the protection automatically and so on .Not only namely the integration of machinery product is human's hand and body extending, human's sense organ and the brains look, has the intellectualized characteristic is the integration of machinery and the machinery electrification distinguishes in the function essence.2. Integration of machinery development condition integration of machinery development may divide into 3 stages roughly.20th century 60's before for the first stage, this stage is called the initial stage .In this time, the people determination not on own initiative uses the electronic technology the preliminary achievement to consummate the mechanical product the performance .Specially in Second World War period, the war has stimulated the mechanical product and the electronic technology union, these mechanical and electrical union military technology, postwar transfers civilly, to postwar economical restoration positive function .Developed and the development at that time generally speaking also is at the spontaneouscondition .Because at that time the electronic technology development not yet achieved certain level, mechanical technical and electronic technology union also not impossible widespread and thorough development, already developed the product was also unable to promote massively. The 20th century 70~80 ages for the second stage, may be called the vigorous development stage .This time, the computer technology, the control technology, the communication development, has laid the technology base for the integration of machinery development . Large-scale, ultra large scale integrated circuit and microcomputer swift and violent development, has provided the full material base for the integration of machinery development .This time characteristic is :①A mechatronics word first generally is accepted in Japan, probably obtains the quite widespread acknowledgment to 1980s last stages in the worldwide scale ;②The integration of machinery technology and the product obtained the enormous development ;③The various countries start to the integration of machinery technology and the product give the very big attention and the support. 1990s later periods, started the integration of machinery technology the new stagewhich makes great strides forward to the intellectualized direction, the integration of machinery enters the thorough development time .At the same time, optics, the communication and so on entered the integration of machinery, processes the technology also zhan to appear tiny in the integration of machinery the foot, appeared the light integration of machinery and the micro integration of machinery and so on the new branch; On the other hand to the integration of machinery system modeling design, the analysis and the integrated method, the integration of machinery discipline system and the trend of development has all conducted the thorough research .At the same time, because the hugeprogress which domains and so on artificial intelligence technology, neural network technology and optical fiber technology obtain, opened the development vast world for the integration of machinery technology .These research, will urge the integration of machinery further to establish the integrity the foundation and forms the integrity gradually the scientific system. Our country is only then starts from the beginning of 1980s in this aspect to study with the application .The State Councilsummary had considered fully on international the influence which and possibly brought from this about the integration of machinery technology developmenttrend .Many universities, colleges and institutes, the development facility and some large and middle scale enterprises have done the massive work to this technical development and the application, does not yield certain result, but and so on the advanced countries compared with Japan still has the suitable disparity.3. Integration of machinery trend of development integrations of machinery are the collection machinery, the electron, optics, the control, the computer, the information and so on the multi-disciplinary overlapping syntheses, its development and the progress rely on and promote the correlation technology development and the progress .Therefore, the integration of machinery main development direction is as follows:3.1 Intellectualized intellectualizations are 21st century integration of machinery technological development important development directions .Theartificial intelligence obtains day by day in the integration of machinery constructor's research takes, the robot and the numerical control engine bedis to the machine behavior description, is in the control theory foundation, the absorption artificial intelligence, the operations research, the computer science, the fuzzy mathematics, the psychology, the physiology and the chaos dynamics and so on the new thought, the new method, simulate the human intelligence, enable it to have abilities and so on judgment inference, logical thinking, independent decision-making, obtains the higher control goal in order to .Indeed, enable the integration of machinery product to have with the human identical intelligence, is not impossible, also is nonessential .But, the high performance, the high speed microprocessor enable the integration of machinery product to have preliminary intelligent or human's partial intelligences, then is completely possible and essential.In the modern manufacture process, the information has become the control manufacture industry the determining factor, moreover is the most active actuation factor .Enhances the manufacture system information-handling capacity to become the modern manufacture science development a key point .As a result of the manufacture system information organization and structure multi-level, makes the information the gain, the integration and the fusion presents draws up the character, information measure multi-dimensional, as well as information organization's multi-level .In the manufacture information structural model, manufacture information uniform restraint, dissemination processing and magnanimous data aspects and so on manufacture knowledge library management, all also wait for further break through.Each kind of artificial intelligence tool and the computation intelligence method promoted the manufacture intelligence development in the manufacture widespread application .A kind based on the biological evolution algorithm computation intelligent agent, in includes thescheduling problem in the combination optimization solution area of technology, receives the more and more universal attention, hopefully completes the combination optimization question when the manufacture the solution speed and the solution precision aspect breaks through the question scale in pairs the restriction .The manufacture intelligence also displays in: The intelligent dispatch, the intelligent design, the intelligent processing, the robot study, the intelligent control, the intelligent craft plan, the intelligent diagnosis and so on are various These question key breakthrough, may form the product innovation the basic research system. Between 2 modern mechanical engineering front science different science overlapping fusion will have the new science accumulation, the economical development and society's progress has had the new request and the expectation to the science and technology, thus will form the front science .The front science also has solved and between the solution scientific question border area .The front science has the obvious time domain, the domain and the dynamic characteristic .The project front science distinguished in the general basic science important characteristic is it has covered the key science and technology question which the project actual appeared.Manufacture system is a complex large-scale system, for satisfies the manufacture system agility, the fast response and fast reorganization ability, must profit from the information science, the life sciences and the social sciences and so on the multi-disciplinary research results, the exploration manufacture system new architecture, the manufacture pattern and the manufacture system effective operational mechanism .Makes the system optimization the organizational structure and the good movement condition is makes the system modeling , the simulation and the optimized essential target .Not only the manufacture system new architecture to makes the enterprise the agility and may reorganize ability to the demand response ability to have the vital significance, moreover to made the enterprise first floor production equipment the flexibility and may dynamic reorganization ability set a higher request .The biological manufacture view more and more many is introduced the manufacture system, satisfies the manufacture system new request.The study organizes and circulates method and technique of complicated system from the biological phenomenon, is a valid exit which will solve many hard nut to cracks that manufacturing industry face from now on currently .Imitating to living what manufacturing point is mimicry living creature organ of from the organization, from match more, from growth with from evolution etc. function structure and circulate mode of a kind of manufacturing system and manufacturing process.The manufacturing drives in the mechanism under, continuously by one's own perfect raise on organizing structure and circulating mode and thus to adapt the process of[with] ability for the environment .For from descend but the last product proceed together a design and make a craft rules the auto of the distance born, produce system of dynamic state reorganization and product and manufacturing the system tend automatically excellent provided theories foundation and carry out acondition .Imitate to living a manufacturing to belong to manufacturing science and life science of"the far good luck is miscellaneous to hand over", it will produce to the manufacturing industry for 21 centuries huge of influence .机电一体化摘要机电一体化是现代科学技术发展的必然结果,本文简述了机电一体化技术的基本概要和发展背景。
中英翻译离心式和往复式压缩机的工作效率特性
离心式和往复式压缩机的工作效率特性Rainer Kurz , Bern hard Win kelma nn , and Saeid Mokhatab往复式压缩机和离心式压缩机具有不同的工作特性，而且关于效率的定义也不同。
本文提供了一个公平的比较准则，得到了对于两种类型机器普遍适用的效率定义。
这个比较基于用户最感兴趣的要求提出的。
此外，对于管道的工作环境影响和在不同负载水平的影响给出了评估。
乍一看，计算任何类型的压缩效率看似是很简单的：比较理想压缩过程和实际压缩过程的工作效率。
难点在于正确定义适当的系统边界，包括与之相关的压缩过程的损失。
除非这些边界是恰好定义的，否则离心式和往复式压缩机的比较就变得有缺陷了。
我们也需要承认，效率的定义，甚至是在评估公平的情况下，仍不能完全回应操作员的主要关心问题：压缩过程所需的驱动力量是什么？要做到这一点，就需要讨论在压缩过程中的机械损失。
随着时间的推移效率趋势也应被考虑，如非设计条件，它们是由专业的流水线规定，或者是受压缩机的工作时间和自身退化的影响。
管道使用的压缩设备涉及到往复式和离心式压缩机。
离心式压缩机用燃气轮机或者是电动马达来驱动。
所用的燃气轮机，总的来说，是两轴发动机，电动马达使用的是变速马达或者变速齿轮箱。
往复压缩机是低速整体单位或者是可分的“高速”单位，其中低速整体单位是燃气发动机和压缩机在一个曲柄套管内。
后者单位的运行在750-1,200rpm范围内(1,800rpm是更小的单位)并且通常都是由电动马达或者四冲程燃气发动机来驱动。
效率要确定任何压缩过程的等熵效率，就要基于测量的压缩机吸入和排出的总焓变为：(S)，于是等熵效率，总压力(P)，温度(T)和熵(h)s[h(p,s) h(P,T)] suctsuctdischsucts[h(p,T) h(p,T)] (Eq.1) suctdischsuctdisch并且加上测量的稳态质量流m，吸收轴功率为：m[h(p,T) h(p,p T)] —I suctdischdischsuct (Eq.2)m。
外文文献及翻译_压缩机,泵,制冷工程
Chemical and Petroleum Engineering, Vol. 40, Nos. 11–12, 2004COMPRESSORS, PUMPS, REFRIGERATION ENGINEERING UPDATING PISTON PUMPS FOR OILPRODUCTIONB. S. Zakharov,1 G. N. Sharikov,2and E. G. Kormishin2The three-plunger acid treatment pump SIN32 and the two-cylinder double-acting pump NPTs-32 with four working chambers (for cementing units) have been updated to control pump delivery. The fluid delivery diagrams for pumps of various designs are examined and the test results are reported.In drilling and oil production, single-acting three-plunger (triplex) pumps or double-acting two-cylinder (duplex) pumps are used.In injecting reagents (clay drilling mud, water, cement, acid, etc.) into wells, depending on the technology applied，it is required to inject the fluid in amounts ranging from the maximum to the minimum in a single operation. If the bed accepts the injected fluid well, it becomes necessary to maximize pump delivery for quick completion of the operation. If on the other hand, the bed does not accept the fluid well, it becomes necessary to reduce pump delivery so as to restrict the injection pressure to the safe limit. At present, because of wear of well (down-hole) equipment, the permissible injectionpressure is not higher than 10–15 MPa..The delivery of a piston (reciprocating) or a plunger (displacement) type of pump can be controlled in the following ways:• by installing several pumps with identical or different pumping capacities;• by changing the drive rotation speed;• by using cylinders (plungers) of the required size;• by channeling a part of the fluid into a bypass; and• by dismounting one or several valves.The first version is used essentially in drilling. In oil production, generally all versions are used either individually or in some combination.All pumping units designed for injection of various fluids (fluidal materials) for cementing, hydraulic formation fracturing, hydraulic sand-jet flushing of sand bridges, and other flushing operations in oil and gas wells are mounted on the chassis of motor vehicles (trucks), tractors, caterpillar (tracked) carriers, and specially made carriages.The operating parameters of the pumps (delivery and injection pressure) depend on the power of the drive and maximum and minimum speed of the engine and the pump. The pump delivery can be changed by changing the number of pump strokes without stopping the engine with the help of a gearbox (by gear shifting) and with stopping of the engine by installing cylinders of the required size. Replacement of the cylinders takes a lot of time and is not always possible in a continuous echnological process. In the existing pumping plants, the delivery variation range is inadequate. At the minimum rotation speed and cylinder diameter, the delivery remains extremely high, and for injecting the fluid into the bed the pressure has to be raised above what is permissible.Assigned by NGDU Zainskneft’, Ékogermet carried out updating of two types of pumps, namely, SIN32 and NPTs-32.In the three-plunger (triplex) acid treatment pump SIN32, for reducing the minimum delivery down to 1.0 m3/h,plungers having a diameter of 125 mm were replaced with plungers having a diameter of 55 mm. As a result, the theoretical pump delivery was reduced from 16 down to 3.3 m3/h. Further reduction of the pump delivery was achieved by reducing the rotation speed of the vehicle engine to the possible minimum (500–600 rpm).Simultaneously with this, a new design of packing glands (sealing devices) of plungers of the UPN55 type was developed.It was based on Zakharov mechanical seal [1], which demonstrated high reliability and durability in sucker-rod (oil) pumps. The sealing units and the pistons with a diameter of 55 mm were made for the SIN32 pump by ÉLKAMneftemash in Perm. Its finishing and testing were done by Ékogermet jointly with NGDU Zainskneft’.The design of the UPN55-type plunger seal is shown in Fig. 1. The combined seal consists of the main threestage mechanical seal 4 and an elastic sealingcollar 2. Each stage of the mechanical seal consists of ten rings that are elastically pressed against each other and simultaneously against the plunger surface. The rings are pressed against theplunger in pairs from the opposite sides. The next pair is turned relative to the preceding one by 90º. The rings are pressed in the axial direction by rubber rings of round cross section and in the radial direction, by rubber girdles with eccentric collars. The plunger 5 is made of steel 45 and is chromium-plated and the sealing rings are of bronze. Threecartridges with mechanical seals were installed in the housing bore 3 with a clearance that helps self-centering of the seals relative to the plunger. The cartridges are pressed together by a round nut 1 through a bushing with the sealing collar 2. There are holes in the housing for injecting oil and draining out the overflow into the receiving (suction) line of the pump.In contrast to the well-known elastic glands, the mechanical seal does not require periodic adjustments and ensures reliable operation of the assembly over a long period [2]. Use of the updated SIN32 pump having a UPN55 type of mechanical plunger seals confirmed that the proposed design operationally fit.From August through December 2003, NGDU Zainskneft’ carried out s even bottom-hole treatments (BHT) of six wells using the updated SIN32 pump. Different types of technological operations were carried out in the wells: mud acid BHT, muriatic (hydrochloric) acid BHT, injection of the reagents SNPKh-9021, MIAPROM, and RMD, for which SIN32 and ATs-32 pumping units were generally used. If acid or any other reagent could not be forced through (injected) at 12–15 MPa pressure, a low-capacity unit was connected with the SIN32 pump. In that case, the injection pressure dropped by 2–4 MPa。
压力之源——泵和压缩机外文文献翻译、中英文翻译
Sources of Pressure -Pumps and CompressorsFundamentally most pumps suitable for pumping hydraulic fluid will operate with air or gas, although most oil pumps make poor air compressors, and some compressors will not operate with incompressible fluid without modification.General considerations. The main requirements of a hydraulic pump capable of delivering sufficiently great a pressure to be of practical use, are:a. Means for controlling fluid leakage either by special seals of close working clearances.b. A substantially uniform, non-pulsating delivery.c. The absence of trapping of fluid during rotation, since the fluid is for all practical purpose incompressible.d. Mechanical balance to a sufficient degree to enable the pump to be run as fast as possible, to reduce bulk for a given output.e. Adequate provision for minimizing the effect of distortion of the working parts, casings, ect., due to the internal pressure in the pump.f. Low clearance volumes so that the pump will act momentarily during priming, or with aerated fluid, as a compressor, to discharge the air through the delivery line, instead of leaving It trapped in the pump.g. Adequate inlet valve or port provision to enable the pump to creat a good suction, or alternatively, as in the case of aircraft, to operate at high altitude, and with relatively thick fluids. It should be noted that the time of opening of the inlet valve or port is almost as important as the size of the port.The main requirements of a good compressor are:a. The smallest possible clearance volume compatible with mechanical clearance; this is because any gas compressed in the clearance volume will expand again instead of being discharged, and will thus adversely affect not only the output of the pump, but the maxium pressure that can be achieved.b. Except on low-pressure pumps, two or more stages of compression with as much intercooling between stages as possible. This is desirable, firstly, to reduce the wastage of work and output due to the gas being compressed adiabatically instead of isothermally, and, secondly, to reduce the overall loss of output due to clearance volume.c. Pre-compression of the air in the pump up to the pressure of the delivery line. Although the normal reciprocating pump with an automatic or spring-load delivery valve will ensure this, some of the rotary compressors have to be ported specially to obtain pre-compression, and with some it is nor possible at into the pump, and thewhole volume has again to be compressed. A rotary compressor with pre-compression cannot be operated with hydraulic fluid.d. Provision for air or water cooling of the cylinder so that the temperature of the air in the compression cannot be operated with hydraulic pump.e. Means for controlling gas leakages during compression either by pistonrings on a reciprocating piston compressor, or fine clearance on the rotary types.f. Adequate inlet valve area to prevent throttling of the incoming air, with the consequent loss of volumetric efficiency.The main types of pump and compressor use pistons, meshing gears or rotating vanes, these having been found to give good high pressure performance. Other types of pumps, such as centrifugal pumps or turbo-compressors, are not used for pressure systems as they do not produce high enough pressure to be useful.Variable Speed Hydraulic SystemsIt is particularly important on many hydraulic systems, as on machine tools, to be able to vary the speed of operation at will. This can be carried out in the following ways, sometimes more than one way being combined:a. By varying the pump output manually;b. By using several pumps in combinations;c. By restricting or throttling the output of a automatically variable delivery pump, or a pump accumulator system, or by throttling the inlet;d. By by-passing part of the pump output with a flow dividing valve;e. By varying the volume of the operating jack.1.Variation in pump delivery. Pump delivery can be varied bya. Alteration in its speed;b. Alteration of its stroke in a variable stroke type of pump;c. Using two or more pumps of different delivery in parallel so that by stopping and starting the pumps in various combinations different total deliveries can obtained.The first system is an easy one when the pump is electrically driven, although the electric motor involved is comparatively complicated for normal requirements. Mechanical variable speed gear boxes have been used successfully with constant speed electric drive.Several of the pump mechanisms previously described can readily be adapted to give a varying output by reducing the working strok manually by means of a controlwheel, etc.The third system is simple enough, but varies the output in fixed steps. Two pumps in parallel can give three ranges of output corresponding toPump A, Pump B, Pump A plus B.Three pumps in parallel can give seven steps corresponding toPump A, Pump A plus B, Pump B plus C,Pump B, Pump A plus C, Pump A plus B plus C.Pump C.Since, however, variable stroke pumps are readily available, such a complication as three pumps in parallel hardly seems worthwhile although the two-pump system is probably excellent for such duties as presses, etc. where a great of the working stroke is at low pressure, where a pump for the final working stroke. Automatic isolation of the low pump can be effected by a valve. Any normal type of automatic cut-out will operate in the low-pressure system to by-pass it, without interference from the other pump.2. Restriction of Pump Output. With a variable delivery pump the flow of oil to the system proper can be metered through a restriction, the delivery of the pump automatically adjusting itself to the reduced flow. An automatic flow control valve or throttle is to be preferred to a simple restrictor. This is an extremely simple system, but is liable to variation of speed owing to change in viscosity of the oil, temperature effects, etc. And the metering restriction may have to be adjusted from time to time to keep the speed constant. On the other hand, it is possible to evolve a restriction compensated for changes. By fitting the flow control valve in either jack line, control in one directions only can be exercised, but note that as the volumes of the jack returning to tank may not be same in both directions, the degree of speed control may not be similar.e of Flow dividing Valves. The flow dividing valves of various types are used to control the speed of a system by –passing part of the pump output, even if at the expense of a slight wastage of power. It is possible to use a selector incorporating several ports, which in turn control of fluid past several different flow dividing valves, giving different rates of flow for each position of the selector.4.Variation in hack volume. Another means of obtaining variable speed from a constant delivery pump is use jacks of different volumes (i.e. at different pressures), either in parallel, or using a multi-volume construction. If, for example, the machinetool side, etc, is filled with two operating jacks, by suitable selection varying speed of operation can be obtained corresponding toa. Use of jack A;b. Use of jack B;c. Use of jack A and B.If B=2A, the speeds are in the order 1,2,3. The combination of two pumps can obviously give 9 speeds, but at the expense of considerably more complication than would appear to be present with a variable delivery pump.Electrohydraulic Servo Systems1.Electrohydraulic systems use low-power electrical signals (of less than say 1 W) for precisely controlling the movements of large power hydraulic pistons and motors (which may be rated at say 7460W or more). The ‘interface’ between the electrical (control) equipment and the hydraulic (power) equipment is the so-called ‘electrohydraulic servo value’. These values are used on systems which must respond both quickly and accurately: aircraft controls are one example and numerically controlled machine tools another, although increasingly stringent specifications for other types of plant are extending their use into most fields. Many mechanisms which use other method s of control particulary if they already employ hydraulics could benefit from incorporating electrohydraulic techniques.Aseessing the suitability of an electronhydraulic servo value for a particular application requires some insight into the features of different valve types which this paper aims to give by explaining their dynamic characteristics. At the end of this paper are also some comments about electrical (control) supplies for such valves.The dynamics analysis of the hydraulic components within a value follows from the previous text and an outline of the dynamic featuresassociated with electromagnetic actuators will be included here a combination of both analyses would simulate a complete valve. However, it is rarely necessary to take full account of most valve s’ dynamic characteristics because their response is usually much more rapid than those of the systems they are used to control. This paper is intended more to give sufficient background information for effectively using such valves than for designing them.2.Flow Control ValveElectrohydraulic flow control valves have a moving coil or moving iron device which positions a main control spool with a high degree of accuracy. The moving coil or moving iron component is called the ‘armature’ and small deflections of the armature cause displacements of the spool either directly by a mechanical link or indirectly via pilot pressure. The main spool can be of the three–way or four-way type and maxium spool displacements are commonly less than 2mm. The widths of spool lands and valve and bore may be as small as 5μm. Particles of ‘dirt’in the fluid should be smaller than the radial clearance, for example smaller than 5μm or 0.0002 in. Each port opening caused by movement of the spool acts as an orifice metering fluid to and from the load.压力之源——泵和压缩机从原理上讲，泵送流体的大多数泵都可以泵送空气或气体，尽管大多数油泵几乎不作为空气压缩机来用，而某些压缩机未作调整则不可以输送非压缩性流体。
离心泵毕业论文中英文资料对照外文翻译文献
离心泵毕业论文中英文资料对照外文翻译文献离心泵中英文资料对照外文翻译文献文献名称（外文）CENTRIFUGAL PUMPS IN THE CHEMICAL INDUSTRYAbstract : A centrifugal pump converts the input power to kinetic energy in the liquid by accelerating the liquid by a revolving device - an impeller. The most common type is the volute pump. Fluid enters the pump through the eye of the impeller which rotates at high speed. The fluid is accelerated radially outward from the pump chasing. A vacuum is created at the impellers eye that continuously draws more fluid into the pump . This article stresses on a series of centrifugal pumps，From a brief introduction to the principles.Keywords: centrifugal pump ,Introduction ,Working principle , Cavitation ，Mechanism of Cavitation ，Solution and Remedies1. IntroductionPump ,device used to raise ,transfer ,or compress liquids and gases .Four general classes of pumps for liquids are described below .In all of them ,steps are taken to prevent cavitation (the formation of a vacuum) ,which would reduce the flow and damage the structure of the pump .Pumps used for gases and vapors are usually known as compressors .The study of fluids in motion is called fluid dynamics.Water pump ,device for moving water from one location to another ,using tubes or other machinery .Water pumps operate under pressures ranging from a fraction of a pound to more than 10,000 pounds per square inch .Everyday examples of water pumps range from small electric pumps that circulate and aerate water in aquariums and fountains to sump pumps that remove water from beneath the foundations of homes .One type of modern pumps used to move water is the centrifugal pump .Early version of the centrifugal pump ,the screw pump ,consists of a corkscrew-shaped mechanism in a pipethat ,when rotated ,pulls water upward .Screw pumps are often used in waste-water treatment plants because they can move large amounts of water without becoming clogged with debris .In the ancient Middle East the need for irrigation of farmland was a strong inducement to develop a water pump .Early pumps in this region were simple devices for lifting buckets of water from a source to a container or a trench .Greek mathematician and inventor Archimedes is thought to have devised the first screw pump in the third century BC .Later Greek inventor Ctesibius develop the first lift pump .During the late 17th and early 18th Centuries AD ,British engineer Thomas Savery ,French physicist Denis Papin ,And British blacksmith and inventor Thomas Newcomen contributed to the development of a water pump that used steam to power the pump’ piston .The steam-powered water pump’s first wide use was in pumping water out of mines .Modern-day examples of centrifugal pumps are those used at the Grand Coulee Dam on the Columbia River .This pump system has the potential to irrigate over one million acres of land .Also known as rotary pumps ,centrifugal pumps have a rotating impeller ,also known as a blade ,that is immersed in the liquid .Liquid enters the pump near the axis of the impeller ,and the rotating impeller sweeps the liquid out toward the ends of the impeller blades at high pressure .The impeller also gives the liquid a relatively high velocity that can be converted into pressure in a stationary part of the pump ,known as the diffuser .In high-pressure pumps ,a number of impeller may be used in series ,and the diffusers following each impeller may contain guide vanes to gradually reduce the liquid velocity .For lower-pressure pumps ,the diffuser is generally a spiral passage ,known as a volute ,with its cross-sectional area increasing gradually to reduce the velocity efficiently .The impeller must be primed before it can begin operation ,that is ,the impeller must be surrounded by liquid when the pump is started .This can be done by placing a check valve in the suction line ,which holds the liquid in the pump when the impeller is not rotating .If this valve leaks ,the pump may need to be primed by the introduction of liquid from an outside source such as the discharge reservoir .A centrifugal pump generally has a valve in the discharge line to control the flow and pressure .For low flows and high pressures ,the action of the impeller is largely radial .For higher flows and lower discharge pressure ,the direction of the flow within the pump is more nearly parallel to the axis of the shaft ,and the pump is said to have an axial flow .The impeller in this case acts as a propeller .The transition from one set of floe conditions to the other is gradual ,and for intermediate condition , the device is called a mixed-flow pump .2.The Centrifugal PumpThe centrifugal pump is by far the most widely used type in the chemical and petroleum industries .It will pump liquids with very wide ranging properties and suspensions with a highsolids content including ,for example ,cement slurries ,and may be constructed from a very wide rang of corrosion resistant materials .The whole pump casing may be constructed from plastic such as polypropylene or it may be fitted with a corrosion-resistant lining .Because it operates at high speed ,it may be directly coupled to an electric motor and it will give a high flow rate for its size .In this type of pump ,the fluid is fed to the centre of a rotating impeller and is thrown outward by centrifugal action .As a result of the high speed of rotation the liquid acquires a high kinetic energy and the pressure difference between the suction and delivery sides arises from the conversion of kinetic energy into pressure energy .The impeller consists of a series of curved vanes so shaped that the flow within the pump is as smooth as possible .The greater the number of vanes on the impeller ,the greater is the control over the direction of the liquid and hence the smaller are the losses due to turbulence and circulation between the vanes .In the open impeller ,the vanes are fixed to a central hub ,whereas in the closed type the vanes are held between two supporting plates and leakage across the impeller is reduced .As will be seen later ,the angle of the tips of the blades very largely determines the operating characteristics of the pump .The liquid enters the casing of the pump，normally in an axial direction，and is picked up by the vanes of the impeller．In the simple type of centrifugal pump，the liquid discharges into a volute，a chamber of gradually increasing cross—section with a tangential outlet．A volute type of pump is shown in Fig.(a)．In the turbine pump[-Fig．(b)]the liquid flows from the moving vanes of the impeller through a series of fixed vanes forming a diffusion ring．This gives a more gradual change in direction to the fluid and more efficient conversion of kinetic energy into pressure energy than is obtained with the volute type．The angle of the leading edge of the fixed vanes should be such that the fluid is received without shock．The liquids flows along the surface of the impeller vane with a certain velocity whilst the tip of the vane is moving relative to the casing of the pump．The direction of motion of the liquid relative to the pump casing--and the required angle of the fixed vanes—is found by compounding these two velocities．In Fig．c，c.v u is the velocity of the liquid relative to the vane and t u is the tangential velocity of the tip of the vane ；compounding these two velocities gives the resultant velocity 2u of the liquid ．It is apparent ，therefore ，that the required vane angle in the diffuser is dependent on the throughput ，the speed of rotation ，and the angle of the impeller blades ．The pump will therefore operate at maximum efficiency only over a narrow range of conditions ．Virtual head of a centrifugal pumpThe maximum pressure is developed when the whole of the excess kinetic energy of the fluid is converted into pressure energy. As indicated below ．the head is proportional to the square of the radius and to the speed ，and is of the order of 60m for a single —stage centrifugal pump ；for higher pressures ，multistage pumps must be used ．Consider the liquid which is rotating at a distance of between r and r+dr from the centre of the pump(Fig ．d)．dThe mass of this element of fluid dm is given by 2πrdrdρ，where ρ is the density of the fluidand 6 is the width of the element of fluid 。
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中英文对照资料外文翻译文献离心式和往复式压缩机的工作效率特性往复式压缩机和离心式压缩机具有不同的工作特性，而且关于效率的定义也不同。
本文提供了一个公平的比较准则，得到了对于两种类型机器普遍适用的效率定义。
这个比较基于用户最感兴趣的要求提出的。
此外，对于管道的工作环境影响和在不同负载水平的影响给出了评估。
乍一看，计算任何类型的压缩效率看似是很简单的：比较理想压缩过程和实际压缩过程的工作效率。
难点在于正确定义适当的系统边界，包括与之相关的压缩过程的损失。
除非这些边界是恰好定义的，否则离心式和往复式压缩机的比较就变得有缺陷了。
我们也需要承认，效率的定义，甚至是在评估公平的情况下，仍不能完全回应操作员的主要关心问题：压缩过程所需的驱动力量是什么？要做到这一点，就需要讨论在压缩过程中的机械损失。
随着时间的推移效率趋势也应被考虑，如非设计条件，它们是由专业的流水线规定，或者是受压缩机的工作时间和自身退化的影响。
管道使用的压缩设备涉及到往复式和离心式压缩机。
离心式压缩机用燃气轮机或者是电动马达来驱动。
所用的燃气轮机，总的来说，是两轴发动机，电动马达使用的是变速马达或者变速齿轮箱。
往复压缩机是低速整体单位或者是可分的“高速”单位，其中低速整体单位是燃气发动机和压缩机在一个曲柄套管内。
后者单位的运行在750-1,200rpm 范围内（1,800rpm 是更小的单位）并且通常都是由电动马达或者四冲程燃气发动机来驱动。
效率要确定任何压缩过程的等熵效率，就要基于测量的压缩机吸入和排出的总焓(h)，总压力(p)，温度(T)和熵(s)，于是等熵效率s η变为：)],(),([)],(),([suct suct disch disch suct suct suct disch s T p h T p h T p h s p h --=η (Eq.1)并且加上测量的稳态质量流m ，吸收轴功率为：)],(),([.suct suct disch disch m T p h T p h m p -=η (Eq.2)考虑机械效率m η。
理论（熵）功耗（这是绝热系统可能出现的最低功耗）如下：)],(),([.suct suct suct disch theor T p h s p h m P -= (Eq.3)流入和流出离心式压缩机的流量可以视为“稳态”。
环境的热交换通常可以忽略。
系统边界的效率计算通常是用吸入和排出的喷嘴。
需要确定的是，系统边界要包含所有内部泄露途径，尤其是从平衡活塞式或分裂墙渗漏的循环路径。
机械效率m η，在描述轴承和密封件的摩擦损失以及风阻损失时可以达到98%和99%。
对于往复式压缩机，理论的气体马力也是由Eq.3给出的，鉴于吸力缓冲器上游和排力缓冲器下游的吸气和排气压力脉动。
往复压缩机就其性质而言，从临近单位需要多方面的系统来控制脉动和提供隔离（包括往复式和离心式），以及可以自然存在的来自管线的管流量和面积管道。
对于任何一个低速或高速单位的歧管系统设计，使用了卷相结合，管道长度和压力降元素来创造脉动（声波）滤波器。
这些歧管系统（过滤器）引起压力下降，因此必须在效率计算时考虑到。
潜在的，从吸气压力扣除的额外压力不得不包含进残余脉动的影响。
就像离心压缩机一样，传热就经常被忽视。
对于积分的机器，机械效率一般取为95%。
对于可分机机械效率一般使用97%。
这些数字似乎有些乐观，一系列数字显示，往复式发动机机械损失在8-15%之间，往复压缩机的在6-12%（参考1往复压缩机招致号码：库尔兹，R.，K.，光布伦，2007）。
工作环境在这样的情况下，当压缩机在一个系统中运行时，管道长度Lu 上游和Ld 下游，以及管道pu 上游的初始压力和管道pe 下游的终止压力均被视为常量，在管道系统中我们有一个压缩机运行的简单模型（图1）。
图1：管道段的概念模型（文献2：库尔兹.R ，M.由罗穆斯基，2006年）。
对于给定的，标准管线定量流动能力将在吸入阶段强加压力s p ，在压缩机放电区强加压力d p 。
对于给定的管线，压缩机站头部（s H ）流（Q ）关系可以近似表述为 ⎥⎥⎥⎥⎥⎥⎦⎤⎢⎢⎢⎢⎢⎢⎣⎡-⎪⎪⎪⎪⎪⎭⎫ ⎝⎛⋅+-=-11112243s k k d s p p Q C C T C H（Eq.4）其中3C 和4C 是常数（对于一个给定的管道几何）分别描述了管道两边的压力和摩擦损失（文献2：库尔兹.R ，M.由罗穆斯基，2006年）。
除去其他问题，这意味着对于带管道系统的压缩机站，头部所需流量扬程是由管道系统规定的（图2）。
特别地，这一特点对于压缩机需要的能力允许头部减量，按照规定的方式反之亦然。
管道因此将不需要改变头部的流量恒定（或压力比）。
图2：建立在4式上的机头流量关系。
在短暂的情况下（如包装其间），最初的操作条件遵循恒功率分布，如头部流量关系如下： const H P s s =⋅=•ηm （Eq.5）Qconst H s s 1⋅⋅=ρη 并将渐进地达到稳定的关系（文献3：奥海宁S.，R.库尔兹，2002年）在上述要求的基础上，必须控制压缩机输出与系统要求匹配。
该系统需求的特点是系统流程和系统头部或压力比的强烈关系。
管线压缩机提供了在操作条件经验下的大量变化，一个重要问题就是如何使压缩机适应这样变化的条件，具体的说就是如何影响效率。
离心压缩机具有相当大的平头部和流程特点。
这意味着压力比的改变对机器的实际流程有重大的影响（文献4：库尔兹R.，20004年）。
对于一个恒速运行的压缩机，头部或压力比随着流量的增加而减少。
控制压缩机内的流程可以实现压缩机不同的运行速度。
这是控制离心压缩机最便捷的方法。
两轴燃气轮机和变速电机允许大范围的速度变化（通常是最大速度或更多的40%或50%到100%）。
应当指出，被控制的值通常不是速度，但速度是间接平衡由涡轮产生的动力（受进入燃气轮机燃油流量控制）和压缩机的吸收功率。
事实上，在过去15年安装的任何离心压缩机在管线服务方面是由调速器来驱使的，通常是两轴燃气轮机。
年长的设施和服务设施在其他管线服务有时使用单轴燃气轮机（允许速度90%到100%的变化）和恒速电动机。
在这些装置中，吸节流或可变进气导叶用来提供控制方法。
图3：典型的管线运行点绘制成的典型离心压缩机性能图。
离心压缩机的运行封套受最大允许速度限制，最小流量（涌）和最大流量（窒息或石墙）（图3）。
另一个限制因素可能是可用的驱动电源。
只有最小流量需要特别注意，因为它被定义为压缩机的一种气动稳定性的极限。
跨越这个限制以降低流动将导致压缩机流动逆转，这可能会损坏压缩机。
调制解调器控制系统通过打开一个循环阀来控制这种情况。
出于这个原因，几乎所有的现代压缩机装置都使用带有控制阀的循环线，当压缩机内的流量趋于稳定极限时这种控制阀允许流量的增加。
控制系统不断地监测压缩机关系喘振线的运行点，并且有必要的话自动地开关循环阀。
对于大多数应用来说，带有开放或部分开放循环阀的运行模式只被用于开启和关闭阶段，或者是在混乱运行条件时的短暂时期。
假设由公式4得到管线特点，压缩机的叶轮将在达到或接近其最大效率时被选出来运行，这个最大效率是由管线强加在整个系列的头部和流量条件下的。
这可能是有一个速度（N ）控制的压缩机，因为一个压缩机的最有效点是由一种关系而连接的，这种关系需要大约（风扇法方程）：525C N H = 6C N Q = 26525C C Q H ⋅= (Eq.6)为满足上述关系的操作点，吸入气压g P 是（基于效率几乎保持不变这个的事实）：37653726557g N C C C Q C C C Q H C P ⋅⋅⋅=⋅⋅=⋅⋅=(Eq.7) 正因为如此，这种力-速度关系允许动力涡轮运行达到或非常接近其整个范围的理想速度。
管线中典型的运行方案允许压缩机和动力涡轮在大多数时间里在最有效点运行。
然而，燃气轮机的燃气生产商将在部分负荷运行时丢失一些热效率。
图3显示了一个典型的实际例子：不同流动要求的管线运行点绘制成用于压缩机站中的速度控制离心压缩机性能图。
往复压缩机将自动服从系统压力比的需求，只要没有超出机械的限制条件（杆负载功率）。
系统吸排气压力的改变将仅能引起阀门或早或晚的开启。
头部可以自动下降因为阀门可以降低排气端的管线压力和/或吸入端更高的管线压力。
因此，如果没有额外的措施，流量将大致恒定——除了容积效率将增加的变化，所以降低压力比而增加流量。
控制的挑战存在于系统要求的流量调整。
如果没有额外的调整，随着压力比的变化，压缩机流量的改变微乎其微。
从历史上看，通过改变激活机器的数量使管线安装许多小的压缩机和调整流量。
这个容量和负荷可通过速度调谐，或者通过一个单一单元的缸间隙中的许多小调整（加载步骤）来调谐。
随着压缩机的发展，控制容量的负担转移到独立压缩机上。
负荷控制是压缩机运行的一个关键组成部分。
从管线操作角度来看，在机组中流量变化要符合管线投出承诺，以及实施公司最佳操作（例如，线包装，负载预期）。
从一个单元的角度来看，负荷控制包含降低单元流量（通过卸载或速度）使操作尽可能的贴近设计扭矩限制，并在压缩机或驱动程序没有超载的情况下进行。
对于任何给定的机组入口和出口压力，在任何负荷图曲线上的关键限制都是杆负荷限制和马力/扭矩限制。
瓦斯控制通常会建立在一个机组的单元上，而这个机组运行必须达到管线流量目标。
地方单元控制将建立负载步骤或速度要求来限制杆负荷或达到扭矩控制。
改变流量的常用方法是改变速度，改变间隙，或取消激活缸头（保持进口阀开启）。
另一种方法是卸载无限步骤，从而延缓吸气阀封闭以减少容积效率。
此外，流程的一部分可以回收或吸气压力可以节流从而降低质量流量，同时保持进入压缩机的容积流量基本不间断。
压缩机控制策略应该能够实现自动化，并在压缩机运行期间能够简便地调整。
特别地，压缩机设计修改的战略需求（如：离心压缩机重新旋转，改变缸径，或给往复压缩机添加固定间隙）在这里不被考虑。
需要指出的是，对于往复式压缩机一个关键的控制要求是不超载驱动或超过机械限制。
运行典型的稳态管道运行将产生图4所示的一个有效行为。
该图是评估沿管道稳定运行特征状态压缩机效率的结果。
大中型压缩机都将达到100%流量的最佳效率，并允许超出设计流量的10%。
不同的机械效率并没有考虑这种对比。
往复压缩机效率在文献5中被推导出，从增加的阀门效率测量与压缩效率和造成的损失脉动衰减器。
低速压缩机的效率是可以实现的。
高速往复压缩机在效率上可能比较低。
图4：以稳态管线特性运行为基础的在不同流量率的压缩机效率。
图4显示在较低压力比下增加的阀门损失的影响和往复机器的较低流量，而离心压缩机的效率几乎保持常量。
结论不同型号压缩机间的效率定义和对比需要密切关注边界条件的定义，对于这样的边界条件，效率和受用的运行发展趋势同时被定义。