A High-efficiency Steam Turbine Utilizing Optimized
高级英语下翻译英汉对照
Isotopes with long half-lives have many uses in medicine and industry, but they must be handled and disposed of with great care, in case they cause radiation damage.
中子被放射出时以高速运动。正如所知，这种高速运动的中子几乎不可能被可裂变铀俘获。
However, if slowed down to thermal speeds, their probability of capture is greatly increased.
然而，如能使中子减速到热运动速度，热中子被俘获的可能性就会大大增加。
有一些裂变产物，例如铯-137,就是一种很有用的辐射源；目前已经能够从废弃的燃料中分离出我们所期望的同位素。
14．Chain Reaction连锁反应
Chain Reaction
连锁反应
When fission occurs, an average of 2-5 neutrons are emitted from the nucleus.
在使用石墨缓和剂的情况下，铀通常以铀棒形式插进石墨切槽内。
These channels areso arranged as toform a lattice structure, the object of which is to reduce neutron escape to a minimum.
如果原子核是重核，也就是说原子核如含有大量质子和中子，就可能更加趋于不稳定。
个人整理的重点专业英语单词(只供参考)
adiabatic 绝热的rotor 转子sophisticated 完善的boiler 锅炉shrink fit 冷缩配合utilize 使用composition 成分，合成物static balance 静平衡welding 焊接condenser 冷凝器turbine 汽轮机，涡轮conduction 导热air heater 空气预热器adiabatic 绝热的control volume 控制体ammonia 氨水combustor 燃烧器convection 对流coal-fired plant 燃煤电站deaeration 除氧dry saturated vapor 干饱和蒸汽compressor 压缩机electrolyte电解液electrolyte 电解，电解液condenser 凝汽器isentropic等熵的fluid mechanics 流体力学critical pressure 临界压力Joule 焦耳free convection 自然对流drain 排水管，排水pressurized加压的isentropic 等熵的gas turbine 燃气轮机reciprocating 往复的isothermal 等温的heat exchanger 换热器recuperation回热转纸phase change 相变latent heat of vaporization 汽化潜热pump 泵power station 电站resonant vibration 共振reversible 可逆的preheating 预热enthalpy焓saturation 饱和pressure difference 差压entropy 熵thermal efficiency 热效率Rankine cycle 朗肯循环evaporator 蒸发器thermodynamics 热力学reliability可靠性latent heat潜热vacuum 真空state-of-the-art 达到最新技术发展水平的compressor 压缩机supercritical pressure 超临界压力thermal resistance 热阻condenser 凝汽器superheated steam 过热蒸汽economizer 省煤器thermal gradient热梯度fatigue 疲劳thermodynamic 热力学的flange 法兰diaphragm pressure sensor 膜片压力传感器velocity速度error 偏差，误差welded 焊接safety valve 安全阀absorption cooling 吸收式制冷aspect ratio(length/chord) 相对高度set point设定值attachment 连接，附件stress 压力blade 叶片，刀片abnormal 异常的boundary layer 边界层auxiliary 辅助的chord 弦，弦长assess 评估critical speed 临界转速category 种类fastening 连系，固紧console 控制台，仪表板fatigue cracking 疲劳断裂debris 碎屑fitting 装配feasibility 可行性impulse 冲量flange 法兰Mach number 马赫数ignition 点火nozzle 喷嘴，喷管initial 初始的nozzle box 喷嘴室log 运行记录表offset 补偿，抵消moisture 水分，湿气purge 清洗parameter 参数resonance 共振portion 部分robust 坚固的，硬的pulverizer 磨煤机refrigerant 制冷剂。
背压式蒸汽汽轮发电机组工艺流程
背压式蒸汽汽轮发电机组工艺流程The process of a back-pressure steam turbine power generation system involves several essential steps. The first step is the production of high-pressure steam in a boiler, which is then fed into the back-pressure steam turbine. This high-pressure steam causes the turbine to rotate, which in turn drives the generator to produce electricity. The steam exiting the turbine is at a lower pressure, which is then used for various industrial processes or for heating purposes.背压式蒸汽汽轮发电机组工艺流程涉及到几个基本步骤。
首先是在锅炉中生产高压蒸汽，然后将其输入背压式蒸汽汽轮发电机。
这种高压蒸汽能使汽轮机旋转，从而驱动发电机产生电能。
汽轮机排出的蒸汽压力降低后，可以用于各种工业过程或供暖。
One of the primary advantages of a back-pressure steam turbine power generation system is the ability to generate both electricity and thermal energy. This dual-purpose capability allows for a more efficient use of the steam produced in the boiler, maximizing the overall energy output of the system. Additionally, the use of back-pressure steam turbines can help industries reduce their reliance on grid electricity and lower their overall energy costs.背压式蒸汽汽轮发电机组的主要优势之一是能够同时产生电力和热能。
新东方四级词汇乱序版
Word List 19saddle 马鞍lest 唯恐creep 爬行afford 承担trial 审判，测验inn 小旅店choke 噎着dental 牙的council 委员会，理事会portion 比例lodge 旅馆troop 军队，一群vague 模糊的tropical 炎热的，热带的coil 一卷benefit 受益troublesome 麻烦的，讨厌的female 女性的pose 造型truly 真诚的peculiar 独特的export 出口resume 重新开始portrait 肖像utter 完全bacteria 细菌idle 闲逛pledge 承诺exchange 交换emotion 情绪harsh 刺耳的exposure 暴露saving 节约reasonable 通情达理的trumpet 唢呐applause 鼓掌nonsense 废话fantasy 幻想usage 用处finance 财政exaggerate 夸大trunk 树桩grocer 杂货店cruise 巡游initial 最初的railroad 铁路tube 管道attain 达到devise 设计density 密度tune 调子source 源shrug 耸肩daylight 日光tunnel 隧道site 位置turbine 涡轮机handy 手边的background 背景tutor 导师sauce 酱汁combine 组合pill 药bay 湾ceremony 典礼formula 公式reservior 水库delete 删除pump 泵backward 向后twist缠绕range 范围niece 侄女protest 反对Word List 20 centimetre 厘米predict 预测acquaintance 熟识learning 学识spider 蜘蛛counsel 忠告commit 犯罪typewriter 打字机sin 罪过sow 播种companion 伙伴destination 目的地typical 典型的corresponding 相关的donkey 驴子frontier 前线outlook 展望，前景typist 打字员apart 分开additional 另外的consequence 结果nevertheless 然而dirt 污秽lobby 前厅occasional 偶然的doubtful 怀疑的committee 委员会tyre 轮胎ugly 丑陋的parallel 平行的cooperate 合作appetite 食欲impose 强迫invade 侵略controversy 争论confident 自信的nursery 育婴房fraction 部分cabinet 橱amid 在...之中manufacturer 制造商independence 独立academic 学院的evolve 进化exception 例外dictation 听写profession 职业authority 权利deposit 积累enquiry 询问differ 区别于argument 争论memorial 纪念碑faculty 系，学科dim 昏暗的moreover 而且earnest 郑重其事地heroic 行英雄的umbrella 雨伞orchestra 管弦乐队arithmetic 算数basically 基本地battery 电池heel 脚后跟oblige 迫使convict 判罪respond 负责cite 引用，举例discard 丢弃grab 抢劫deceive 欺骗senior 高级的modest 谦虚的continuous 连续不断的Word List 21comprise 包括revolt 反叛expense 消耗campus 校园mold 霉菌insure 保险cash 现金virtue 优点violent 狂暴的react 反应odd 奇怪的diverse 不同的manual 手工的uncover 覆盖ban 禁止confront 直面undergo 经历journal 杂志emperor 君王undergraduate 大学肄业生circular 循环的dictate 听写inform 通知underground 地铁hook 钩underline 下划线male 雄性的proceed 前进hydrogen 氢force 力fog 雾fluid 流体drill 钻机understanding 理解的nitrogen 氮commission 委员会jaw 颌undertake 承诺salary 工资skilled 熟练地assembly 集会merry 快乐undo 解开扣子undoubtedly 毫无疑问地globe 全球的uneasy 不舒服precious 珍贵的mosquito 蚊子petroleum 汽油favourable 赞同的sightseeing 观光economic 经济的multiple 多重的poverty 贫困rely 依赖effort 努力accumulate 积累cheat 欺骗humorous 幽默的rare 罕见的rival 对手echo 回声investment 投资collapse 倒塌corridor 走廊despite 不顾pit 坑counter 柜台balcony 楼厅diplomatic 外交的cigar 雪茄bathe 洗澡conquer 征服inflation 膨胀Word List 22 thermometer 温度计worthwhile 值得scenery 景色terror 恐怖average 平均democracy 共和slap 掴obstacle 障碍occur 出现nuisance 讨厌的人significance 重要性up-to-date 最新的justify 证明...有理neglect 无视membership 会员身份union 联合roller 辊压机formation 形成punctual 守时的relieve 减缓candy 糖果spokesman 发言人employer 雇主unique 独特的mathematics 数学herd 群cheerful 鼓舞人心的advertise 打广告reflexion（=reflection）反射unite 联合secure 安全的mineral 矿石universal 普遍的lane 小径beloved 亲爱的adapt 适应mislead 误导drag 拖flash 闪immigrant 移民remarkable 令人惊叹的increasingly 越来越indoor 室内的palm 手掌exclusive 奢侈的namely 即universe 宇宙burst 爆发preferable 更好的filter 滤过anyhow 不管怎么样score 得分qualify 满足条件global 全球的heave 起伏，举unless 除非excessive 过分的marine 海军behalf 利益，方面advanced 高级的，领先的soda 苏打unlike 不像adjust 调整unload 卸下leader 领导spelling 拼写accordingly 一致anxiety 焦躁ridiculous 荒谬的unusual 不寻常的scholarship 奖学金divorce 离婚headquarters 总部commerce 商业Word List 23torture 折磨fashion 时尚incident 小事upset 失落underneath 在...下面recover 恢复theory 理论evolution 进化myth 神话trim 整洁的mud 泥浆unfortunately 不幸地relate 联系，相关extraordinary 不凡的debt 债urge 急切做urgent 急切的qualification 资格satellite 卫星publication 出版cliff 峭壁restrain 克制commander 指挥官carpet 地毯peer 凝视highway高速公路breed 饲养ensure 确保requirement 要求attempt 努力flock 群largely 很大程度上restraint 克制focus 集中protective 保护性的utility 效用jet 喷气飞机coordinate 协调restore 恢复receipt 收据contrary 相反方面Christian 基督教徒hardware 硬件bloom 开花dragon 龙specimen 标本chew 咀嚼utmost 极度的original 初始的religion 宗教communication 交流beyond 超出vacant 空的conclude 做结论restrict 阻止respectively 分别fairly 公平sailor 海员，水手remark 评论assure 使确信balance 平衡campaign 运动，战役psychological 心理学的contradiction 矛盾，否定dose 一剂vacation 假期immediately 立即vacuum 真空ore 矿石clause 从句cattle 牲口barn 牲口棚laser 激光initiative 主动性，首创精神compel 使屈服Word List 24basis 基础contact 接触guarantee 保证semiconductor 半导体rib 肋骨obvious 明显的geometry 几何butcher 屠夫triumph凯旋maid 女仆eyesight 视力interview 采访vain 无劳paste 浆糊soak 浸泡exceed 超越boom 激增item 项目hammer 榔头metric 米制的jar 罐头resource 资源compose 创作military 军事package 包裹van 货车，领导者，先驱besides 另外injection 注射laboratory 实验室vanish 消失experimental 实验的mysterious 神秘的sake 缘故keen 强烈的vapour 蒸汽haste 急忙magic 魔法poisonous 有毒的aid 援助coach 教练decrease 降低relief 缓解continual 连续的slight 轻微的stare 凝视grace 优雅band 带，乐团mechanical 力学的considerate 体贴的ditch 沟渠ignorance 天真，无知balloon 气球brake 刹车data 数据bake 烘焙gear 齿轮patient 耐心的altitude 海拔inquiry 询问implement 贯彻，执行remind 提醒pint 品脱engine 发动机bid 叫价scout 侦查mould 霉菌avenue 林荫道instance 例子career 事业fountain 喷泉format 格式correspond 相关Word List 25clarify 澄清mercy 恩惠expression 表示exact 确实decade 十年dimension 维度vision 视unity 统一vigorous 活力的via 通过skim 略读severe 严重的conquest 征服improve 提高variety 种类election 选举expert 专家dive 跳水various 多种多样的rifle 来福步枪stake 刑柱，股份corporation 合作vary 呈现不同eagle 山鹰figure 数字，人vast 广阔的simplify 简化instead 替代shell 贝壳drawer 抽屉quote 引号，引用depress 使压抑schedule 日程表limitation 限制disturb 打扰cancer 癌症accord 一致industrial 工业的preference 偏爱screen 屏幕error 错误gratitude 毕业slam 关门evil 邪恶的accent 口音imagination 想象力elsewhere 其余地方champion 冠军framework 框架social 社会的endure 忍受gradual 逐渐的sleeve 袖子concession 承认，许可vehicle 交通工具register 注册apology 道歉luggage 行李desperate 极渴望的billion 十亿venture 商业冒险queue 队列aside 一边reflect 反射beneficial 有益的repeatedly 反复地kindergarten 幼儿园verify 核实reduction 减少version 版本implication 暗示accustomed 习惯的helicopter 直升机normal 普通的Word List 26shiver 颤抖stadium 体育馆grasp 抓住economy 经济rotten 腐烂的dash 猛冲recently 最近地concept 概念rigid 死板的entertain 使娱乐vertical 垂直的vessel 管道evident 明显的apologize 道歉scholar 学者costly 昂贵的veteran 老士兵glimpse 一瞥finally 最终approval 准许judgement 判断regulation 管理，规章cord 绳powder 粉末improvement 提高remote 遥远的provide 提供rub 揉搓fiction 小说occurrence 出现adopt 接受navigation 航海adventure 探险float 漂浮dynamic 动力学的vibrate 振动indifferent 冷漠的plot 线索horror 恶心的fatigue 疲劳consideration 考虑vice 堕落notebook 笔记本chop 劈respect 方面admission 准许disease 疾病ignore 忽视infect 影响confirm 证明harbour 港口concrete 坚实的organic 有机的phase 相previous 预先的helpless 无助的amaze 使惊奇despair 绝望victim 受害者possibility 可能性video 视频viewpoint 观点erect 矗立obey 遵守rarely 很少地vinegar 醋approach 方式，达到violate 违反distinction 显著不同holy 神圣的philosophy 哲学golf 高尔夫outward 向外的section 部分penalty 惩罚Word List 27dump 倾销internal 内部的installation 安装charge 掌管，电荷criticize 批评disorder 混乱rocket 火箭dessert 甜点dispute 辩论butterfly 蝴蝶circuit 环路frequent 频繁的depart 离开lens 透镜sigh 叹息violence 暴力reserve 保存aluminium 铝hence 所以pine 松木opening 开始，空缺acid 酸hen 母鸡giant 巨大的crystal 水晶，晶体operational 可执行的racial 种族的construction 结构planet 行星image 图像blade 刀刃physicist 物理学家sack 麻袋behave 行为organism 有机体shortly 简短地interval 间隔violet 紫罗兰draught 拖拉appointment 约定meantime 同时murder 谋杀violin 小提琴perspective 远景，透视图laundry 洗衣房virtual 事实上virtually事实上calculate 计算confess 承认appearance 外貌virus 病毒ambulance 救护车，野战队liberty 自由consequently 因此所以insist 坚持要求，认为solar 太阳的flourish 装修correspondence 联系pronoun 代词property 财产shave 剃刮selection 选举limited 限制的enormous 大量的，巨大的impact 影响visible 可见的conceal 隐藏earthquake 地震curriculum 课程feature 特点loaf 屋顶stain 玷污demand 要求，需求media 媒介comparative 相比的Word List 28massive 重的，巨大的ultimate 最终extent 面积，长度employment 雇佣medium 居中的urban 城市的engineering 工程marvelous 不可思议的event 大事resolve 决心avoid 避免respective 分别boast 自夸sew 缝纫indicate 暗示govern 掌控visual 可视的utilize 利用chase 追赶prevail 说服pillow 枕头packet 包heap 堆variation 多样性primary 初级的dense 密集的outside 外面owe 欠interfere 干涉burden 压力scatter 传播，分散starve 挨饿simplicity 简朴bare 裸露的compound 化合物orderly 有序的resolution 决心learned 有教养的shelter 藏身之处reporter 记者profile 侧脸shed 库棚necessarily 必要地vitamin 维生素reproduce 再生产grateful 感激的convenience 方便vivid 生动的outset 开始deserve 值得assignment 指派，分配principal 校长enable 使能够refrigerator 冰箱keyboard 键盘poison 毒药mill 磨坊electrical 电的install 安装output 产量ally 联盟vocabulary 词汇athlete 运动员honourable 光荣的brass 黄铜merely 仅仅地engage 花时间做，订婚sphere 球，球状的purple 紫色volcano 火山decline 下降classic 传统的stale 腐烂的Word List 29liberate 自由，解放standpoint 立场activity 活动volt 伏特arrange 安排canal 运河device 装置voltage 电压angle 角度volume 容量voluntary 志愿的rhythm 韵律bore 使枯燥marriage 婚姻bet 打赌spade 铁锹official 官方的beast 野兽drum 鼓crash 冲撞boot 长筒靴charm 魅力literature 文学handbag 手提包volunteer 志愿者oval 椭圆的glorious 光荣的inspire 使振奋精神protection 保护argue 争论cop 警察given 规定的，给定的chapter 章节likely 有可能的omit 省略，遗漏adequate 充分的departure 分开according 已知的shift 改变sophisticated 老于世故的damp 潮湿的fry 炸extension 延伸instruction 说明，引荐assumption 假定potential 潜在的permanent 永久的quit 放弃region 地域overseas 海外的vote 选票furnace 装修wagon 四轮马车agriculture 农业oven 电炉waist 腰editor 编辑republican 共和主义者factor 因素hint 暗示waken 唤醒plunge 骤降applicable 适当的wander 散步luxury 奢侈品loosen 松的readily 乐意地devil 魔鬼border 国界warmth 温暖creative 创造性的waterproof 防水的cargo 货物complaint 抱怨Word List 30explosion 爆炸economical 节约的progressive 进步的residence 阻力的，抵抗的resemble 类似于perception 感知annoy 扰乱whichever 不管哪个whereas 然而rob 打劫recommend 推荐pitchperform 表演connect 连接pilot 飞行员vital 必不可少的scold 训斥intense 强烈的horrible 恶心的，可怕的edition 版次speculate 猜想，投机mechanism 机制，机理dumb 哑的handwriting 手写educate 教育landlord 地主glove 手套scope 范围recovery 恢复weaken 使衰弱refusal 拒绝wealth 财富overall 整体上reputation 名声ending 结局spill 溢出character 字母，特点notify 通知pollute 污染persist 坚持principle 原则peak 山峰margin 页边空白regarding 关于repetition 重复spectacular 壮观的humour 幽默感achievement 成就salad 沙拉fare 车费flame 火焰convention 习俗network 网络reservation 保存ribbon 缎带plentiful 丰富的classify 分类weapon 武器dissolve 溶解splendid 壮观的scarce 少见的politics 政治学alphabet 字母表performance 表演clumsy 笨拙的ax 斧子wealthy 富裕的detect 发觉physician 物理学家guy 家伙administration 政府emphasize 强调frost 冻坏Word List 31 contribution 贡献weave 编织crane 起重机muscle 肌肉admire 羡慕，崇拜exclude 排除inquire 询问dialect 方言weed 杂草accident 事故Negro 黑人identify 识别instrument 器具scratch 抓dependent 依靠的moral 道德的individual 单独的loan 借出divide 分chin 下巴shield 盾牌minimum 最小的lump 肿块loose 释放scissors 剪刀diameter 直径soar 酸痛molecule 分子gaze 凝视relationship 关系reality 现实risk 危险fee 费mature 成熟的provided 提供的curiosity 求知欲，好奇心organ 器官grind 碾碎harmony 和谐lamb 羊羔column 栏目weekly 每周riot 暴乱being 人plus 加nightmare 梦魇budget 预算chart 聊天，表格porter 搬运工人dusk 黄昏somewhat 有一点weep 流泪weld 焊接competition 竞赛gallon 加仑convert 皈依publish 出版market 市场kneel 跪postpone 延迟liter 升click 点击logical 逻辑的convince 使相信headline 提要disaster 灾难welfare 福利pierce 刺入ankle 踝关节radiation 放射线origin 初始well-known 著名的exhaust 耗尽hardship 困难Word List 32bubble 泡intimate 亲密的defeat 战胜bacon 咸肉creature 生物optional 可以任选的probable 大概的fuss 大惊小怪的wax 蜡nucleus 原子核financial 财政的sequence 顺序concede 承认，让步brand 商品junior 年少的whale 鲸whatsoever 任何relax 放松fireman 消防员crust 面包皮observation 观察mention 提及guideline 指导方针insight 洞察力nuclear 核能的seminar 研讨会colony 殖民地jeans 牛仔裤deliberate 故意的catalog 目录salesman 售货员liver 肝inevitable 必然的deck 甲板arrangement 整理forbid 禁止account 账目operator 话务员whilst 当…的时候lid 盖子humble 简陋的descend 下降furniture 家具aggressive 好斗的footstep 足迹invent 发明plantation 种植园accurate 准确的mankind 人类log 原木pessimistic 悲观的neighbourhood 四邻glow 发白热光injure 伤害objective 目标alter 改变electricity 电apparent 明显的arrow 箭occupy 占hunt 打猎poll 民意测验grape 葡萄capacity 容量refresh 振作精神guidance 引导ounce 盎司applicant 申请人ashamed 惭愧的draft 草稿whip 鞭笞philosopher 哲学家greenhouse 温室Word List 33 competitive 竞争的destruction 破坏application 申请impatient 急躁的logic 逻辑negotiate 协商germ 细菌whisper 低语withdraw 撤回aspect 方面require 要求beam 面露喜色smash 粉碎responsible 有责任感的accompany 陪伴affection 感情detail 细节commercial 商业的efficiency 效率organization 组织whistle 口哨injury 伤害refugee 难民embarrass 使为难inhabitant 居民province 省collective 集体的ruin 毁灭resist 反抗genius 天才quotation 引文hut 小屋community 社区isolate 使隔离whoever 无论谁snap 仓促的ache 疼痛optical 光学的alarm 警报wholly 全部的semester 学期impress 给…留下印象fate 命运resistant 抵抗的maximum 最大量wicked 坏的possess 拥有widen 加宽widespread 分布广的active 积极地beard 胡须classification 分类postage 邮费widow 寡妇accidental 偶然happen 碰巧element 成分era 时代arise 出现poem 诗explosive 爆炸的width 宽度grammar 语法wisdom 智慧insult 侮辱freight 货运physical 身体的conversely 相反地wit 风趣location 位置hostile 不友善的reject 拒绝purchase 购买Word List 34jewel 宝石determination 决心preliminary 初步的withstand 反抗insect昆虫civil 公民的scrape 刮blast 爆炸witness 证人melt 融化scream 尖叫hopeless 绝望的wolf 狼sacrifice 牺牲forge 伪造lover 情人connection 联系possession 所有wool 羊毛identical 完全相同的preceding 前面的workshop 车间entry 入口处digest 消化rate 比率define 限定fulfill 履行generous 慷慨的owner 物主passive 消极的chaos 混乱workman 工人motive 动机attract 吸引revise 修改senate 参议院observe 观察alcohol 酒精settlement 解决radar 雷达gum 口香糖worm 虫grip 抓紧optimistic 乐观的nature 本性brilliant 卓越的worldwide 遍及全球的inferior 下等的audio 听觉的circulate 循环abandon 丢弃assist 协助pattern 型index 索引worship 崇拜fleet 舰队mixture 混合currency 货币outlet 出口facility 设备attorney 律师regulate 管理intend想要brick 砖measure 测量claw 爪rat 鼠feasible 可行的parcel包裹worthless 无用的leap 跳horizon 地平线socialism 社会主义Word List 35 influence 影响力document文件worthy 值得的dot 点heading 标题naval 海军的oxygen 氧roar 吼叫fluent 流利的poet 诗人gym 体育馆resign 辞职wrap 包sexual 性的endless 无止境的occupation 占领extra 额外的intensive 集中的candidate 候选人wreck 失事aboard 上船（飞机）festival 节日single 单一的federal 联邦的microscope 显微镜classical 古典的attach 附加zone 地区deaf 聋的spoil损坏wrist 腕accuracy 准确性invisible 看不见的association 协会writer 作家writing 书写X-ray X光civilian 平民gaol =jailhire 雇用confuse 使困惑garbage 垃圾overtake 超过gravity 重力yawn 打哈欠sideways 从一边的bundle 捆leather 皮革concentration 专注portable 便携的elegant 优美的spray 浪花yearly 每年的funeral 葬礼acute 严重的ghost 鬼halt 停止complex 综合体coarse 粗的patch 补丁favourite 特别喜爱的rust 铁锈await 等候acquire 取得prejudice 偏见yield 出产bolt 螺栓generate 发生gallery 画廊existence 存在percentage 百分比specific 特有的youngster 青年熟词僻义表act 法令address 演说advance 前进age 年老aim 针对air 晾干appear 发表arm 以武器装备article 条款atom 微粒attend 照顾bad 严重的badly 严重地bar 阻拦battle 作战bear 写有belt 区block 街区blue 忧郁的body 尸体book 预定boss 指挥bother 麻烦bow 蝴蝶结box 拳击branch 分部bridge 桥牌button 扣紧can 罐头capital 资金catch 领会celebrate 歌颂cell 电池chair 主席change 零钱cheap 卑鄙的china 瓷器class 阶级coat 表皮code 准则coin创造collect 对方付费的company 连队composition 构成concert 一致content 满足的correct 纠正course 一道菜crop 一批custom 海关daily 日报deal分给deed 契约degree 学位deliver给产妇接生description 种类desert 离弃duty税edge 优势employ 使忙于even 均匀的exit 退出express 快车,快递fail 使失望fair 白皙的familiar 冒昧的fan 狂热爱好者file 把…归档film 胶卷fine 罚金fire 解雇firm 公司flow 流动fly 苍蝇garage汽车修理行general 将军gift 天赋goal 得分golden 极好的hand 指针handsome 相当大的head 率领hear 审讯heavy 密集地hero 男主角hide 兽皮hit 成功而风行一时的事物hot 辣的house 议院ice 冰镇immediate 直接的industry 勤劳iron熨kill 消磨(时间) last 持续lead 铅letter 字母library 藏书lift 电梯live 活的lonely 荒凉的long 渴望lot 阄mad 恼火的mark 斑点master 硕士match 火柴mean 吝啬的might 力量mine 矿minute 微细的mirror 反射moon 卫星next 贴近的novel 新颖的nurse 看护order 命令paper 论文park 停车场part 角色period 学时permit 执照piece 拼合pipe烟斗plain 清楚的plane平面plant 工厂plate 平板play 演奏please 使高兴pool 共有post 柱pound 捣碎power 使开动present 介绍president 会长press新闻界pretty 很,相当pride 自夸prize 珍视program 节目单pronounce 宣布pupil 瞳孔race 种族rapid 急流reason 推理receive 接待refer 参考rest 停留revolution 旋转role 作用room 余地rough 粗略的row 划rush 催促safe 保险箱sandwich 夹入中间satisfaction 赔偿(物) save 除…之外school 学派season 时节sentence 判决share 股份sharp 敏锐的shoot 疾驰shoulder肩负silence 使沉默skirt边缘society 上流社会soil弄脏sort 整理sound 健康的spare 饶恕spring 泉stage 阶段stamp 跺脚stomach 食欲student 研究生succeed 继承suggest 暗示suit 起诉sunny 快活的table 项目表tank 大容器tap 窃听tear 撕开tell 区分terrible 极度的ticket 罚款单tip 小费tired 厌倦的tower 高耸treasure 珍视treat 款待try 审问uniform 制服unit 部件value 估价voyage 旅行wage开展(运动) want 需要water灌溉well井wind 缠绕world 领域wound 使受伤超纲单词表abundance 大量accommodate 容纳aerial 飞机的aisle 过道ambitious 有抱负的applaud 向…鼓掌appraisal 估计auction 拍卖aviation 航空bachelor 单身汉baffle 使困惑ballet 芭蕾舞beforehand 预先blockade 封锁breakthrough 突破briefcase 公文包brutal 野兽般的calorie 卡casualty 伤亡人员census 人口普查chronic 慢性的chronological 按年代排序cling 紧紧抓住cognitive 认知的commonplace 普通的compensate 补偿concise 简明的conform 遵守consequent 结果console 安慰continuity 连续cooperative 合作的corporate 法人团体的costume 服装courtesy 谦恭有礼coverage 新闻报道creation 创造cumulative 积累的deadly 致命的decisive 决定性的defiance 违抗deficiency 不足destructive 破坏的diligent 勤勉的disastrous 灾难性的distract 转移注意力divine 神的dock 码头donate 捐献endurance 忍耐力energetic 精力充沛的enrich 充实enthusiastic 满腔热情的erosion 腐蚀eternal 永远的ethnic 种族的expedition 远征fake 假货fitting 设备flaw 缺点foster 收养grim 讨厌的guidepost 路标heighten 提高heir 继承人heritage 遗产hum 哼曲子humanity 人类hurricane 飓风iceberg 冰山identification 认出ignition 点火illusion 幻想imaginative 富于想象力的imitation 模仿imperative 必要的indicative 指示的induce 诱导inland 内陆的instrumental 有帮助的interact 相互作用invariably 不变地irrigation 灌溉likelihood 可能literacy 识字locality 地点,位置lounge 闲逛memoir 论文集memorize 记住monetary 钱的monopoly 垄断morality 道德muscular 强壮的notwithstanding 尽管nurture 养育nutritious 有营养的olive 橄榄optimum 最佳的paperback 平装本pedestrian 行人permissible 许可的pest 害虫physiological 生理学的plague 鼠疫preach 宣讲premature 不成熟的prescription 药方prestige 威信prevalent 流行的productive 多产的productivity 生产力profess 表示profitable 有益的profound 深远的prophecy 预言prospective未来的pumpkin 南瓜purity 纯洁pursuit 追求quest 寻找random 任意的rap 敲击recite 朗诵reconcile 使协调recycle 回收利用referee 裁判员relay 接力赛repertoire 全部节目residential居住的reunion 团聚revelation 新发现revenge 报复revolve 旋转scrutiny 仔细观察seemingly 表面上silicon 硅slogan 标语smuggle 走私snack 快餐solitary 孤独的stability 稳定stationary 静止不动的stereo 立体声stern 严厉的subjective 主观的subordinate 下级的sue 控告telecommunication 通信thereafter 之后tile 瓦timely 及时地token 纪念品tolerant 宽容的toll 损失tract 传单transient 临时的transition 转变tuition 学费unemployment 失业unify 使联合upbringing 教养versus 对vicious 邪恶的vigor 精力vita 个人简历vocal 发声的vulnerable 脆弱的wallet 皮夹子wardrobe 衣柜warfare 战争wrinkle 皱纹。
板式换热器外文文献(英文)
DESIGN OF HEAT EXCHANGER FOR HEAT RECOVERY IN CHP SYSTEMSABSTRACTThe objective of this research is to review issues related to the design of heat recovery unit in Combined Heat and Power (CHP) systems. To meet specific needs of CHP systems, configurations can be altered to affect different factors of the design. Before the design process can begin, product specifications, such as steam or water pressures and temperatures, and equipment, such as absorption chillers and heat exchangers, need to be identified and defined. The Energy Engineering Laboratory of the Mechanical Engineering Department of the University of Louisiana at Lafayette and the Louisiana Industrial Assessment Center has been donated an 800kW diesel turbine and a 100 ton absorption chiller from industries. This equipment needs to be integrated with a heat exchanger to work as a Combined Heat and Power system for the University which will supplement the chilled water supply and electricity. The design constraints of the heat recovery unit are the specifications of the turbine and the chiller which cannot be altered.INTRODUCTIONCombined Heat and Power (CHP), also known as cogeneration, is a way to generate power and heat simultaneously and use the heat generated in the process for various purposes. While the cogenerated power in mechanical or electrical energy can be either totally consumed in an industrial plant or exported to a utility grid, the recovered heat obtained from the thermal energy in exhaust streams of power generating equipment is used to operate equipment such as absorption chillers, desiccant dehumidifiers, or heat recovery equipment for producing steam or hot water or for space and/or process cooling, heating, or controlling humidity. Based on the equipment used, CHP is also known by other acronyms such as CHPB (Cooling Heating and Power for Buildings), CCHP (Combined Cooling Heating and Power), BCHP (Building Cooling Heating and Power) and IES (Integrated Energy Systems). CHP systems are much more efficient than producing electric and thermal power separately. According to the Commercial Buildings Energy Consumption Survey, 1995 [14], there were 4.6 million commercial buildings in the United States. These buildings consumed 5.3 quads of energy, about half of which was in the form of electricity. Analysis of survey data shows that CHP meets only 3.8% of the total energy needs of the commercial sector. Despite the growing energy needs, the average efficiency of power generation has remained 33% since 1960 and the average overall efficiency of generating heat and electricity using conventional methods is around 47%. And with the increase in prices in both electricity and natural gas, the need for setting up more CHP plants remains a pressing issue. CHP is known to reduce fuel costs by about 27% [15] CO released into the atmosphere. The objective of this research is to review issues related to the design of heat recovery unit in Combined Heat and Power (CHP) systems. To meet specific needs of CHP systems, configurations can be altered to affect differentfactors of the design. Before the design process can begin, product specifications, such as steam or water pressures and temperatures, and equipment, such as absorption chillers and heat exchangers, need to be identified and defined.The Mechanical Engineering Department and the Industrial Assessment Center at the University of Louisiana Lafayette has been donated an 800kW diesel turbine and a 100 ton absorption chiller from industries. This equipment needs to be integrated to work as a Combined Heat and Power system for the University which will supplement the chilled water supply and electricity. The design constraints of the heat recovery unit are the specifications of the turbine and the chiller which cannot be altered.Integrating equipment to form a CHP system generally does not always present the best solution. In our case study, the absorption chiller is not able to utilize all of the waste heat from the turbine exhaust. This is because the capacity of the chiller is too small as compared to the turbine capacity. However, the need for extra space conditioning in the buildings considered remains an issue which can be resolved through the use of this CHP system. BACKGROUND LITERATUREThe decision of setting up a CHP system involves a huge investment. Before plunging into one, any industry, commercial building or facility owner weighs it against the option of conventional generation. A dynamic stochastic model has been developed that compares the decision of an irreversible investment in a cogeneration system with that of investing in a conventional heat generation system such as steam boiler combined with the option of purchasing all the electricity from the grid [21]. This model is applied theoretically based on exempts. Keeping in mind factors such as rising emissions, and the availability and security of electricity supply, the benefits of a combined heat and power system are many.CHP systems demand that the performance of the system be well tested. The effects of various parameters such as the ambient temperature, inlet turbine temperature, compressor pressure ratio and gas turbine combustion efficiency are investigated on the performance of the CHP system and determines of each of these parameters [1]. Five major areas where CHP systems can be optimized in order to maximize profits have been identified as optimization of heat to power ratio, equipment selection, economic dispatch, intelligent performance monitoring and maintenance optimization [6].Many commercial buildings such as universities and hospitals have installed CHP systems for meeting their growing energy needs. Before the University of Dundee installed a 3 MW CHP system, first the objectives for setting up a cogeneration system in the university were laid and then accordingly the equipment was selected. Considerations for compatibility of the new CHP setup with the existing district heating plant were taken care by some alterations in pipe work so that neither system could impose any operational constraints on the other [5]. Louisiana State University installed a CHP system by contracting it to Sempra EnergyServices to meet the increase in chilled water and steam demands. The new cogeneration system was linked with the existing central power plant to supplement chilled water and steam supply. This project saves the university $ 4.7 million each year in energy costs alone and 2,200 emissions are equivalent to 530 annual vehicular emissions.Another example of a commercial CHP set-up is the Mississippi Baptist Medical Center. First the energy requirement of the hospital was assessed and the potential savings that a CHP system would generate [10]. CHP applications are not limited to the industrial and commercial sector alone. CHP systems on a micro-scale have been studied for use in residential applications. The cost of UK residential energy demand is calculated and a study is performed that compares the operating cost for the following three micro CHP technologies: Sterling engine, gas engine, and solid oxide fuel cell (SOFC) for use in homes [9].The search for different types of fuel cells in residential homes finds that a dominant cost effective design of fuel cell use in micro – CHP exists that is quickly emerging [3]. However fuel cells face competition from alternate energy products that are already in the market. Use of alternate energy such as biomass combined with natural gas has been tested for CHP applications where biomass is used as an external combustor by providing heat to partially reform the natural gas feed [16]. A similar study was preformed where solid municipal waste is integrated with natural gas fired combustion cycle for use in a waste-to-energy system which is coupled with a heat recovery steam generator that drives a steam turbine [4]. SYSTEM DESIGN CONSIDERATIONSIntegration of a CHP system is generally at two levels: the system level and the component level. Certain trade-offs between the component level metrics and system level metrics are required to achieve optimal integrated cooling, heating and power performance [18]. All CHP systems comprise mainly of three components, a power generating equipment or a turbine, a heat recovery unit and a cooling device such as an absorption chiller.There are various parameters that need to be considered at the design stage of a CHP project. For instance, the chiller efficiency together with the plant size and the electric consumption of cooling towers and condenser water pumps are analyzed to achieve the overall system design [20]. Absorption chillers work great with micro turbines. A good example is the Rolex Reality building in New York, where a 150 kW unit is hooked up with an absorption chiller that provides chilled water. An advantage of absorption chillers is that they don’t require any permits or emission treatment [2]Exhaust gas at 800°F comes out of the turbine at a flow rate of 48,880 lbs/h [7]. One important constraint during the design of the CHP system was to control the final temperature of this exhaust gas. This meant utilizing as much heat as required from the exhaust gas and subsequently bringing down the exit temperature. After running different iterations on temperature calculations, it was decided to divert 35% of the exhaust air to the heat exchanger whilethe remaining 65% is directed to go up the stack. This is achieved by using a diverter damper. In addition, diverting 35% of the gas relieves the problem of back pressure build-up at the end of the turbine.A diverter valve can also used at the inlet side of the heat exchanger which would direct the exhaust gas either to the heat exchanger or out of the bypass stack. This takes care of variable loads requirement. Inside the heat exchanger, exhaust gas enter the shell side and heats up water running in the tubes which then goes to the absorption chiller. These chillers run on either steam or hot water.The absorption chiller donated to the University runs on hot water and supplies chilled water. A continuous water circuit is made to run through the chiller to take away heat from the heat input source and also from the chilled water. The chilled water from the absorption chiller is then transferred to the existing University chilling system unit or for another use.Thermally Activated DevicesThermally activated technologies (TATs) are devices that transform heat energy for useful purposed such as heating, cooling, humidity control etc. The commonly used TATs in CHP systems are absorption chillers and desiccant dehumidifiers. Absorption chiller is a highly efficient technology that uses less energy than conventional chilling equipment, and also cools buildings without the use of ozone-depleting chlorofluorocarbons (CFCs). These chillers can be powered by natural gas, steam, or waste heat.Desiccant dehumidifiers are used in space conditioning by removing humidity. By dehumidifying the air, the chilling load on the AC equipment is reduced and the atmosphere becomes much more comfortable. Hot air coming from an air-to-air heat exchanger removes water from the desiccant wheel thereby regenerating it for further dehumidification. This makes them useful in CHP systems as they utilize the waste heat.An absorption chiller is mechanical equipment that provides cooling to buildings through chilled water. The main underlying principle behind the working of an absorption chiller is that it uses heat energy as input, instead of mechanical energy.Though the idea of using heat energy to obtain chilled water seems to be highly paradoxical, the absorption chiller is a highly efficient technology and cost effective in facilities which have significant heating loads. Moreover, unlike electrical chillers, absorption chillers cool buildings without using ozone-depleting chlorofluorocarbons (CFCs). These chillers can be powered by natural gas, steam or waste heat.Absorption chiller systems are classified in the following two ways:1. By the number of generators.i) Single effect chiller –this type of chiller, as the name suggests, uses one generator and the heat released during the absorption of the refrigerant back into the solution is rejected to the environment.ii) Double effect chiller –this chiller uses two generators paired with a single condenser, evaporator and absorber. Some of the heat released during the absorption process is used to generate more refrigerant vapor thereby increasing the chiller’s efficiency as more vapor is generated per unit heat or fuel input. A double effect chiller requires a higher temperature heat input to operate and therefore its use in CHP systems is limited by the type of electrical generation equipment it can be used with.iii) Triple effect chiller –this has three generators and even higher efficiency than a double effect chiller. As they require even higher heat input temperatures, the material choice and the absorbent/refrigerant combination is limited.2. By type of input:i) Indirect-fired absorption chillers –they use steam, hot water, or hot gases from a boiler, turbine, engine generator or fuel cell as a primary power input. Indirect-fired absorption chillers fit well into the CHP schemes where they increase the efficiency by utilizing the otherwise waste heat and producing chilled water from it.ii) Direct-fired absorption chillers –they contain burners which use fuel such as natural gas. Heat rejected from these chillers is used to provide hot water or dehumidify air by regenerating the desiccant wheel.An absorption cycle is a process which uses two fluids and some heat input to produce the refrigeration effect as compared to electrical input in a vapor compression cycle in the more familiar electrical chiller. Although both the absorption cycle and the vapor compression cycle accomplish heat removal by the evaporation of a refrigerant at a low pressure and the rejection of heat by the condensation of refrigerant at a higher pressure, the method of creating the pressure difference and circulating the refrigerant remains the primary difference between the two. The vapor compression cycle uses a mechanical compressor that creates the pressure difference necessary to circulate the refrigerant, while the same is achieved by using a secondary fluid or an absorbent in the absorption cycle [11].The primary working fluids ammonia and water in the vapor compression cycle with ammonia acting as the refrigerant and water as the absorbent are replaced by lithium bromide (LiBr) as the absorbent and water (H2O) as the refrigerant in the absorption cycle. The process occurs in two shells - the upper shell consisting of the generator and the condenser and the lower shell consisting of the evaporator and the absorber.Heat is supplied to the LiBr/H2O solution through the generator causing the refrigerant (water) to be boiled out of the solution, as in a distillation process. The resulting water vapor passes into the condenser where it is condensed back into the liquid state using a condensing medium. The water then enters the evaporator where actual cooling takes place as water is passes over tubes containing the fluid to be cooled.Heat ExchangerA very low pressure is maintained in the absorber-evaporator shell, causing the water to boil at a very low temperature. This results in water absorbing heat from the medium to be cooled and thereby lowering its temperature. The heated low pressure vapor then returns to the absorber where it mixes with the LiBr/H2O solution low in water content. Due to the solution’s low water content, vapor gets easily absorbed resulting in a weaker LiBr/H2O solution. This weak solution is pumped back to the generator where the process repeats itself.The heat recovery steam generator (HRSG) is primarily a boiler which generates steam from the waste heat of a turbine to drive a steam turbine. The heat recovery boiler design for cogeneration process applications covers many parameters. The boiler could be designed as a fire-tube, water tube or combination type. Further for each of these parameters, there is a variety of tube sizes and fin configurations. For a given boiler, a simplified method that determines the boiler performance has been developed [8].The shell and tube heat exchanger is the most common and widely used heat exchanger in different industrial applications [13]. It is compared to a classic instrument in a concert playing all the important nodes in different complex system set-ups and can be improved by using helical baffles. There are other ways to augment the heat transfer in a shell and tube exchanger such as through the use of wall-radiation [25].The design of a shell and tube heat exchanger fora combined heat and power system basically involves determining its size or geometry by predicting the overall heat transfer coefficient (U). The process of obtaining the heat transfer coefficient values is obtained from literature by correlating results from previous findings in the determination of heat exchanger designs.This involves listing assumptions at the beginning of the procedure, obtaining fluid properties, calculation of Reynolds number and the flow area to obtain the shell and tube sizes. Once U is calculated, the heat balances are calculated. This study also compares the theoretical U values with the actual experimental ones to prove the theoretical assumptions and to obtain the optimum design model [18].A mathematical simulation for the transient heat exchange of a shell and tube heat exchanger based on energy conservation and mass balance can be used to measure the performance. The design of the heat exchanger is optimized with the objective function being the total entropy generation rate considering the heat transfer and the flow resistance [20].Once a heat exchanger is designed, a total cost equation for the heat exchanger operation is deduced. Based on this, a program is developed for the optimal selection of shell-tube heat exchanger [24].The heat exchanger to be used in the CHP system in the end needs to be tested for its performance. A heat recovery module f orcogeneration is tested before use for CHP application through a microprocessor based control system to present the system design and performance data [19].The basis of a CHP system lies in efficiently capturing thermal energy and using it effectively. Generally in CHP systems, the exhaust gas from the prime mover is ducted to a heat exchanger to recover the thermal energy in the gas. The commonly used heat recovery systems are heat exchangers and Heat Recovery Steam Generators depending on whether hot water or steam is required.The heat exchanger is typically an air-to-water kind where the exhaust gas flows over some form of tube and fin heat exchange surface and the heat from the exhaust gas is transferred to make hot water. Sometimes, a diverter or a flapper damper is used to maintain a specific design temperature of the hot water or steam generation rate by regulating the exhaust flow through the heat exchanger.The HRSG is essentially a boiler that captures the heat from the exhaust of a prime mover such as a combustion turbine, gas or diesel engine to make steam. Water is pumped and circulated through the tubes which are heated by exhaust gases at temperatures ranging from 800°F to 1200°F. The water can then be held under high pressure to temperatures of 370°F or higher to produce high pressure steam [21].The Delaware method is a rating method regarded as the most suitable open-literature available for evaluating shell side performance and involves the calculation of the overall heat transfer coefficient and the pressure drops on both the shell and tube side for single-phase fluids [12]. This method can be used only when the flow rates, inlet and outlet temperatures, pressures and other physical properties of both the fluids and a minimum set of geometrical properties of the shell and tube are known. Emission ControlEmission control technologies are used in the CHP systems to remove SO2 (sulphur dioxide), SO3 (sulphur trioxide) NOx (nitrous oxide) and other particulate matter present in the exhaust of a prime mover. Some common emission control technologies are:1、Diesel Oxidation Catalyst (DOC) –They are know to reduce emissions of carbon monoxide by 70 percent, hydrocarbons by 60 percent, and particulate matter by 25 percent (Emissions Control : CHP Technologies Gulf Coast CHP 2007) when used with the ultra-low sulfur diesel (ULSD) fuel. Reductions are also significant with the use of regular diesel fuel.2、Diesel Particulate Filter (DPF) - DPF can reduce emissions of carbon monoxide, hydrocarbons, and particulate matter by approximately 90 to 95 percent (Emissions Control : CHP Technologies Gulf Coast CHP 2007). However, DPF are used only in conjunction with ultra-low sulfur diesel (ULSD) fuel.3、Exhaust Gas Recirculation (EGR) – They have a great potential for reducing NOx emissions.4、Selective Catalytic Reduction (SCR) –SCR cuts down high levels of NOx by reducing NOx to nitrogen (N2) and oxygen (O2).5、NOx absorbers –catalysts are used which adsorb NOx in the exhaust gas and dissociates it to nitrogen.CONCLUSIONSThe various components needed in a CHP system have been presented. Important parameters such as the mass flow rates of the exhaust gas and water can then be defined. The CHP system has been integrated by the use of a heat recovery unit, the design of which has been discussed. A shell and tube configuration is commonly selected based on literature survey. The pressure drops at both the shell and the tube side can be calculated after the exchanger has been sized.Integrating equipment to form a CHP system generally does not always present the best solution. In our case study, the absorption chiller is not able to utilize all of the waste heat from the turbine exhaust. Approximately 65% goes is left to go out the stack. This is because the capacity of the chiller is too small as compared to the turbine capacity. However, the need for extra space conditioning in the buildings considered remains an issue which can be resolved through the use of this CHP system.The heat exchanger designed can either be constructed following the TEMA standards or it can be built and purchased from an industrial facility. The design that is used is based on the methodology of the Bell-Delaware method and the approach is purely theoretical, so the sizing may be slightly different in industrial design. Also the manufacturing feasibility needs to be checked.After the heat exchanger is constructed, the CHP equipment can be hooked together. Again since the available equipment is integrated to work as a system, the efficiency of the CHP system needs to be calculated. Some kind of co ntrol module needs to be developed that can monitor the performance of the entire system. Finally, the cost of running the set-up needs to be determined along with the air-conditioning requirements.。
5_Steam turbine(课堂PPT)
1.3 Difference between steam engine and steam turbine
The turbine compared with engine:
in much larger capacities occupies less floor space much lighter less vibration requires a lighter foundation
The reaction stage (反动式） the pressure drop is divided over both the stationary and rotating row
11
3.2 Velocity change
A pure impulse stage: The velocity rises in nozzles but falls in the blades
10
3 Impulse and Reaction Blading
3.1 Pressure drop
A pure impulse stage (冲动式）
pressure drop across the stationary row no pressure drop across the rotating row
6
2 General Principles
FORCE
STEAM OFF
STEAM IN
The general principle of steam turbine
7
2.1 General principles
Energy conversion
the law of Momentum
Energy conservation
高科技英文名词
高科技英文名词Here is an essay on the topic of "High-Tech English Terminology" with more than 1000 words, written in English without any additional title or punctuation marks.The ever-evolving landscape of technology has given rise to a plethora of new concepts and innovations that have become an integral part of our daily lives. As the field of technology continues to expand, so too does the need for a common language to effectively communicate these advancements. This has led to the widespread adoption of English as the primary language of the tech industry, with a vast array of specialized terminology emerging to describe the various components and functionalities of high-tech systems.At the heart of this linguistic evolution are the unique English terms that have been coined to capture the essence of cutting-edge technologies. These terms often serve as a bridge between the technical complexities of the digital world and the everyday language used by the general public. From the ubiquitous "smartphone" to the enigmatic "blockchain," these high-tech English words have become the lingua franca of the modern technological landscape.One of the most prominent examples of high-tech English terminology is the concept of "artificial intelligence" or AI. This term encompasses a broad range of computational systems and algorithms designed to mimic and surpass human cognitive abilities. AI-powered technologies have revolutionized industries ranging from healthcare to transportation, with applications such as machine learning, natural language processing, and computer vision becoming increasingly prevalent in our daily lives.Another key term in the high-tech lexicon is "cloud computing," which refers to the delivery of computing services, including storage, processing power, and software, over the internet. The rise of cloud computing has transformed the way we access and utilize digital resources, allowing for greater scalability, flexibility, and cost-efficiency in a wide range of applications.The proliferation of the internet and digital communication has also given rise to a host of related high-tech terms, such as "the internet of things" (IoT), which describes the network of interconnected devices and sensors that exchange data and enable remote control and automation. The "internet of things" has paved the way for the development of "smart home" technologies, where household appliances and systems can be managed and monitored through digital interfaces.In the realm of digital security, terms like "cybersecurity" and "encryption" have become increasingly important as the world becomes more reliant on digital infrastructure. Cybersecurity refers to the protection of computer systems, networks, and data from unauthorized access, while encryption is the process of converting information into a coded format to prevent unauthorized access.The rapid advancements in display technologies have also given rise to a new set of high-tech English terms, such as "OLED" (organic light-emitting diode) and "4K" (a resolution standard with four times the pixel count of 1080p HD). These terms have become ubiquitous in the consumer electronics industry, as manufacturers strive to offer ever-more immersive and high-quality visual experiences.In the realm of renewable energy, terms like "solar photovoltaics" and "wind turbine" have become increasingly prominent as the world seeks to transition towards more sustainable power sources. These technologies harness the power of the sun and wind to generate electricity, reducing our reliance on fossil fuels and mitigating the impact of climate change.The field of biotechnology has also contributed a wealth of high-tech English terminology, with concepts like "gene editing," "stem cell research," and "bioinformatics" becoming integral to ourunderstanding of the life sciences. These terms describe the innovative techniques and technologies that are transforming our ability to understand, manipulate, and harness the power of living organisms.As the pace of technological change continues to accelerate, the need for a shared language to describe these advancements becomes ever more crucial. The high-tech English terms that have emerged in recent decades serve as a testament to the ingenuity and creativity of the human mind, as we strive to capture the complexity of the digital world in a clear and concise manner.Moreover, the widespread adoption of these specialized terms has facilitated global collaboration and knowledge-sharing within the tech industry, enabling the rapid dissemination of ideas and the accelerated development of new technologies. By establishing a common lexicon, high-tech English terminology has become a unifying force, bridging linguistic and cultural divides to drive innovation and progress on a global scale.In conclusion, the high-tech English terminology that has emerged in the modern era is a reflection of the transformative power of technology and the human capacity for innovation. From artificial intelligence to cloud computing, these specialized terms have become the building blocks of the digital age, enabling us tonavigate the complex and ever-evolving landscape of technological advancement. As we continue to push the boundaries of what is possible, the high-tech English lexicon will undoubtedly continue to expand, shaping the way we communicate, collaborate, and envision the future.。
毕业设计水利水电工程英文文献翻译
外文文献：hydraulicturbines and hydro-electric powerAbstractPower may be developed from water by three fundamental processes : by action of its weight, of its pressure, or of its velocity, or by a combination of any or all three. In modern practice the Pelton or impulse wheel is the only type which obtains power by a single process the action of one or more high-velocity jets. This type of wheel is usually found in high-head developments. Faraday had shown that when a coil is rotated in a magnetic field electricity is generated. Thus, in order to produce electrical energy, it is necessary that we should produce mechanical energy, which can be used to rotate the ‘coil’. The mechanical energy is produced by running a prime mover (known as turbine ) by the energy of fuels or flowing water. This mechanical power is converted into electrical power by electric generator which is directly coupled to the shaft of turbine and is thus run by turbine. The electrical power, which is consequently obtained at the terminals of the generator, is then transited to the area where it is to be used for doing work.he plant or machinery which is required to produce electricity (i.e. prime mover +electric generator) is collectively known as power plant. The building, in which the entire machinery along with other auxiliary units is installed, is known as power house.Keywords hydraulic turbines hydro-electric power classification of hydel plants head schemeThere has been practically no increase in the efficiency of hydraulic turbines since about 1925, when maximum efficiencies reached 93% or more. As far as maximum efficiency is concerned, the hydraulic turbine has about reached the practicable limit of development. Nevertheless, in recent years, there has been a rapid and marked increase in the physical size and horsepower capacity of individual units.In addition, there has been considerable research into the cause and prevention of cavitation, which allows the advantages of higher specific speeds to be obtained at higher heads than formerly were considered advisable. The net effect of this progress with larger units, higher specific speed, and simplification and improvements in design has been to retain for the hydraulic turbine the important place which it haslong held at one of the most important prime movers.1. types of hydraulic turbinesHydraulic turbines may be grouped in two general classes: the impulse type which utilizes the kinetic energy of a high-velocity jet which acts upon only a small part of the circumference at any instant, and the reaction type which develops power from the combined action of pressure and velocity of the water that completely fills the runner and water passages. The reaction group is divided into two general types: the Francis, sometimes called the reaction type, and the propeller type. The propeller class is also further subdivided into the fixed-blade propeller type, and the adjustable-blade type of which the Kaplan is representative.1.1 impulse wheelsWith the impulse wheel the potential energy of the water in the penstock is transformed into kinetic energy in a jet issuing from the orifice of a nozzle. This jet discharge freely into the atmosphere inside the wheel housing and strikes against the bowl-shaped buckets of the runner. At each revolution the bucket enters, passes through, and passes out of the jet, during which time it receives the full impact force of the jet. This produces a rapid hammer blow upon the bucket. At the same time the bucket is subjected to the centrifugal force tending to separate the bucket from its disk. On account of the stresses so produced and also the scouring effects of the water flowing over the working surface of the bowl, material of high quality of resistance against hydraulic wear and fatigue is required. Only for very low heads can cast iron be employed. Bronze and annealed cast steel are normally used.1.2 Francis runnersWith the Francis type the water enters from a casing or flume with a relatively low velocity, passes through guide vanes or gates located around the circumstance, and flows through the runner, from which it discharges into a draft tube sealed below the tail-water level. All the runner passages are completely filled with water, which acts upon the whole circumference of the runner. Only a portion of the power is derived from the dynamic action due to the velocity of the water, a large part of the power being obtained from the difference in pressure acting on the front and back of the runner buckets. The draft tube allows maximum utilization of the available head, both because of the suction created below the runner by the vertical column of water and because the outlet of he draft tube is larger than the throat just below the runner, thus utilizing a part of the kinetic energy of the water leaving the runner blades.1.3 propeller runnersnherently suitable for low-head developments, the propeller-type unit has effected marked economics within the range of head to which it is adapted. The higher speed of this type of turbine results in a lower-cost generator and somewhat smaller powerhouse substructure and superstructure. Propeller-type runners for low heads andsmall outputs are sometimes constructed of cast iron. For heads above 20 ft, they are made of cast steel, a much more reliable material. Large-diameter propellers may have individual blades fastened to the hub.1.4 adjustable-blade runnersThe adjustable-blade propeller type is a development from the fixed-blade propeller wheel. One of the best-known units of this type is the Kaplan unit, in which the blades may be rotated to the most efficient angle by a hydraulic servomotor. A cam on the governor is used to cause the blade angle to change with the gate position so that high efficiency is always obtained at almost any percentage of full load.By reason of its high efficiency at all gate openings, the adjustable-blade propeller-type unit is particularly applicable to low-head developments where conditions are such that the units must be operated at varying load and varying head. Capital cost and maintenance for such units are necessarily higher than for fixed-blade propeller-type units operated at the point of maximum efficiency.2. thermal and hydropowerAs stated earlier, the turbine blades can be made to run by the energy of fuels or flowing water. When fuel is used to produce steam for running the steam turbine, then the power generated is known as thermal power. The fuel which is to be used for generating steam may either be an ordinary fuel such as coal, fuel oil, etc., or atomic fuel or nuclear fuel. Coal is simply burnt to produce steam from water and is the simplest and oldest type of fuel. Diesel oil, etc. may also be used as fuels for producing steam. Atomic fuels such as uranium or thorium may also be used to produce steam. When conventional type of fuels such s coal, oil, etc. (called fossils ) is used to produce steam for running the turbines, the power house is generally called an Ordinary thermal power station or Thermal power station. But when atomic fuel is used to produce steam, the power station, which is essentially a thermal power station, is called an atomic power station or nuclear power station. In an ordinary thermal power station, steam is produced in a water boiler, while in the atomic power station; the boiler is replaced y a nuclear reactor and steam generator for raising steam. The electric power generated in both these cases is known as thermal power and the scheme is called thermal power scheme.But, when the energy of the flowing water is used to run the turbines, then the electricity generated is called hydroelectric power. This scheme is known as hydro scheme, and the power house is known as hydel power station or hydroelectric power station. In a hydro scheme, a certain quantity of water at a certain potential head is essentially made to flow through the turbines. The head causing flow runs the turbine blades, and thus producing electricity from the generator coupled to turbine. In this chapter, we are concerned with hydel scheme only.3.classification of hydel plantsHydro-plants may be classified on the basis of hydraulic characteristics as follow: ①run-off river plants .②storage plants.③pumped storage plants.④tidal plants. they are described below.(1)Run-off river plants.These plants are those which utilize the minimum flow in a river having no appreciable pondage on its upstream side. A weir or a barrage is sometimes constructed across a river simply to raise and maintain the water level at a pre-determined level within narrow limits of fluctuations, either solely for the power plants or for some other purpose where the power plant may be incidental. Such a scheme is essentially a low head scheme and may be suitable only on a perennial river having sufficient dry weather flow of such a magnitude as to make the development worthwhile.Run-off river plants generally have a very limited storage capacity, and can use water only when it comes. This small storage capacity is provided for meeting the hourly fluctuations of load. When the available discharge at site is more than the demand (during off-peak hours ) the excess water is temporarily stored in the pond on the upstream side of the barrage, which is then utilized during the peak hours.he various examples of run-off the river pant are: Ganguwal and Kolta power houses located on Nangal Hydel Channel, Mohammad Pur and Pathri power houses on Ganga Canal and Sarda power house on Sarda Canal.The various stations constructed on irrigation channels at the sites of falls, also fall under this category of plants.(2) Storage plantsA storage plant is essentially having an upstream storage reservoir of sufficient size so as to permit, sufficient carryover storage from the monsoon season to the dry summer season, and thus to develop a firm flow substantially more than minimum natural flow. In this scheme, a dam is constructed across the river and the power house may be located at the foot of the dam such as in Bhakra, Hirakud, Rihand projects etc. the power house may sometimes be located much away from the dam (on the downstream side). In such a case, the power house is located at the end of tunnels which carry water from the reservoir. The tunnels are connected to the power house machines by means of pressure pen-stocks which may either be underground (as in Mainthon and Koyna projects) or may be kept exposed (as in Kundah project).When the power house is located near the dam, as is generally done in the low head installations ; it is known as concentrated fall hydroelectric development. But when the water is carried to the power house at a considerable distance from the dam through a canal, tunnel, or pen-stock; it is known as a divided fall development.(3) Pumped storage plants.A pumped storage plant generates power during peak hours, but during theoff-peak hours, water is pumped back from the tail water pool to the headwater pool for future use. The pumps are run by some secondary power from some other plant in the system. The plant is thus primarily meant for assisting an existing thermal plant or some other hydel plant.During peak hours, the water flows from the reservoir to the turbine and electricity is generated. During off-peak hours, the excess power is available from some other plant, and is utilized for pumping water from the tail pool to the head pool, this minor plant thus supplements the power of another major plant. In such a scheme, the same water is utilized again and again and no water is wasted.For heads varying between 15m to 90m, reservoir pump turbines have been devised, which can function both as a turbine as well as a pump. Such reversible turbines can work at relatively high efficiencies and can help in reducing the cost of such a plant. Similarly, the same electrical machine can be used both as a generator as well as a motor by reversing the poles. The provision of such a scheme helps considerably in improving the load factor of the power system.(4) Tidal plantsTidal plants for generation of electric power are the recent and modern advancements, and essentially work on the principle that there is a rise in seawater during high tide period and a fall during the low ebb period. The water rises and falls twice a day; each fall cycle occupying about 12 hours and 25 minutes. The advantage of this rise and fall of water is taken in a tidal plant. In other words, the tidal range, i.e. the difference between high and low tide levels is utilized to generate power. This is accomplished by constructing a basin separated from the ocean by a partition wall and installing turbines in opening through this wall.Water passes from the ocean to the basin during high tides, and thus running the turbines and generating electric power. During low tide，the water from the basin runs back to ocean, which can also be utilized to generate electric power, provided special turbines which can generate power for either direction of flow are installed. Such plants are useful at places where tidal range is high. Rance power station in France is an example of this type of power station. The tidal range at this place is of the order of 11 meters. This power house contains 9 units of 38,000 kW.4.Hydro-plants or hydroelectric schemes may be classified on the basis of operating head on turbines as follows: ①low head scheme (head<15m),②medium head scheme (head varies between 15m to 60 m) ,③high head scheme (head>60m). They are described below:(1) Low head scheme.A low head scheme is one which uses water head of less than 15 meters or so. A run off river plant is essentially a low head scheme, a weir or a barrage is constructed to raise the water level, and the power house is constructed either in continuation withthe barrage or at some distance downstream of the barrage, where water is taken to the power house through an intake canal.(2) Medium head schemeA medium head scheme is one which used water head varying between 15 to 60 meters or so. This scheme is thus essentially a dam reservoir scheme, although the dam height is mediocre. This scheme is having features somewhere between low had scheme and high head scheme.(3) High head scheme.A high head scheme is one which uses water head of more than 60m or so. A dam of sufficient height is, therefore, required to be constructed, so as to store water on the upstream side and to utilize this water throughout the year. High head schemes up to heights of 1,800 meters have been developed. The common examples of such a scheme are: Bhakra dam in (Punjab), Rihand dam in (U.P.), and Hoover dam in (U.S.A), etc.The naturally available high falls can also be developed for generating electric power. The common examples of such power developments are: Jog Falls in India, and Niagara Falls in U.S.A.水轮机和水力发电摘要水的能量可以通过三种基本方法来获得：利用水的重力作用、水的压力作用或水的流速作用，或者其中任意两种或全部三种作用的组合。
燃气蒸汽联合循环发电供热流程及原理
燃气蒸汽联合循环发电供热流程及原理燃气蒸汽联合循环发电供热流程包括燃气燃烧、锅炉产生蒸汽、蒸汽驱动涡轮发电、余热发生产蒸汽供热。
The process of combined cycle power generation and heating with gas-steam includes gas combustion, steam generation by boiler, steam driving turbine for power generation, and waste heat producing steam for heating.燃气燃烧产生热能，使锅炉内的水转化为蒸汽，为涡轮发电机提供动力。
Gas combustion produces heat energy, which converts water in the boiler into steam to provide power for the turbine generator.涡轮发电后的余热通过余热锅炉再产生蒸汽用于供热。
The waste heat from the turbine generation is used to produce steam for heating in the waste heat boiler.利用燃气蒸汽联合循环发电供热技术，实现了能源的高效利用。
The combined cycle power generation and heating with gas-steam technology achieves efficient utilization of energy.该技术可以降低能源消耗，提高电力发电效率，还可以实现供热与发电的双重效益。
This technology can reduce energy consumption, improve the efficiency of power generation, and achieve dual benefits of heating and power generation.燃气蒸汽联合循环发电供热流程综合利用了煤炭、天然气等能源资源。
STEAM TURBINE
专利名称：STEAM TURBINE发明人：TIMMINS, Cyril,SMITH, Keith,CHIM, Yuk, Tai,YUNG, Bruce, Pak, Keung申请号：GB1994001013申请日：19940511公开号：WO94/027034P1公开日：19941124专利内容由知识产权出版社提供摘要：A steam turbine system comprises a steam turbine (6) driving electric generator (10), a heat recovering steam generator (8), and a gas turbine (2) driving electric generator (4). The steam generator (8) converts feed water into steam using heat exchanger coils (22, 24, 26, 28, 30 and 32) disposed at different places along a duct (20) carrying the hot exhaust gases from the gas turbine in directions A and B. Coil (22) is a boiler feed water heater, (24) a low pressure evaporator, (26) an economiser, (28) a high pressure evaporator, (30) a reheater, and (32) a superheater. The steam turbine has a high pressure cylinder (34), and intermediate pressure cylinder (36), and a low pressure cylinder (38). Superheater (32) supplies high pressure steam to the cylinder (34), reheater (30) supplies intermediate pressure steam to the cylinder (36) which supplies an output of low pressure steam to the cylinder (38). A fuel gas burner (56) is mounted in the duct between the superheater (32) and the reheater (30) to provide heat augmenting the heat in the exhaust gases. If desired another fuel gas burner (58) may be provided between the reheater (30) and the evaporator (28), and/or another fuel gas burner (60) may be provided between the gas turbine (2) and the superheater (32). The fuel gas can be natural gas which may power the gas turbine (2). The system can be used to generateelectric power in a power station.申请人：TIMMINS, Cyril,SMITH, Keith,CHIM, Yuk, Tai,YUNG, Bruce, Pak, Keung 地址：GB,GB,GB,GB,GB国籍：GB,GB,GB,GB,GB代理机构：KINRADE, John更多信息请下载全文后查看。
蒸汽涡轮机英文作文
蒸汽涡轮机英文作文英文回答：Steam turbines are a type of turbine that utilizessteam as its working fluid. They are commonly employed in various industries, including power generation, propulsion for ships and other vessels, and industrial applications. The conversion of heat energy present in steam into mechanical energy is the fundamental principle behind the operation of steam turbines.Steam turbines consist of several essential components:1. Steam Inlet: The high-pressure steam is directedinto the turbine through a steam inlet.2. Nozzle: The nozzle is responsible for expanding the steam, converting its pressure energy into kinetic energy.3. Rotor: The rotor is the rotating part of the turbine,comprising blades that are attached to the rotor shaft.4. Stator: The stator is the stationary part of the turbine, housing blades that are arranged around the rotor blades.5. Exhaust Outlet: The steam, after passing through the stator blades, exits the turbine through the exhaust outlet.The operation of a steam turbine involves the following steps:1. High-pressure steam enters the turbine through the steam inlet.2. The steam expands through the nozzle, gainingvelocity and losing pressure.3. The high-velocity steam impinges on the rotor blades, causing them to rotate.4. As the steam passes through the stator blades, itexerts a force on the stator blades, which in turn applies a torque to the rotor shaft.5. The rotation of the rotor shaft is utilized to drivea generator, compressor, or other mechanical device.Steam turbines offer numerous advantages, including:1. High Efficiency: Steam turbines can achieve high thermal efficiencies, converting a significant portion of the heat energy in steam into mechanical energy.2. Reliability: Steam turbines are known for their reliability and durability, with some turbines operatingfor decades with minimal maintenance.3. Scalability: Steam turbines can be designed and manufactured in a wide range of sizes and capacities, catering to various power generation requirements.4. Fuel Flexibility: Steam turbines can operate on a variety of fuels, including fossil fuels, nuclear energy,and renewable energy sources such as biomass.5. Environmental Compatibility: Steam turbines can be equipped with emission control systems to minimize environmental impact, making them a relatively clean source of energy.中文回答：蒸汽涡轮机是一种以蒸汽为工作流体的涡轮机。
蒸汽涡轮机英文作文
蒸汽涡轮机英文作文Title: The Steam Turbine - A Pioneering Invention in Energy ConversionThe steam turbine is a remarkable invention that revolutionized the field of energy conversion. This mechanical device extracts energy from pressurized steam and converts it into rotational motion, making it a crucial component in various industrial applications, particularly in power generation.The steam turbine operates on the principle of thermodynamics. Pressurized steam is directed into the turbine, where it expands and rotates the turbine blades. This rotational motion is then harnessed to perform work, such as driving a generator to produce electricity.The efficiency and reliability of the steam turbine have made it a preferred choice in power plants worldwide. Its ability to convert thermal energy into mechanical energy with minimal losses has been a key factor in its widespread adoption. Furthermore, the steam turbine is highly scalable, allowing it to be tailored to meet the specific needs ofdifferent power plants, from small-scale industrial applications to large-scale utility plants.The impact of the steam turbine on society is immense. It has been instrumental in powering industrial revolution, enabling the production of goods and services on an unprecedented scale. Moreover, the widespread use of steam turbines in power generation has contributed to the availability of affordable and reliable electricity, which is crucial for modern society.However, the steam turbine is not without its challenges. The high temperatures and pressures involved in its operation require robust materials and precise engineering. Additionally, the maintenance of steam turbines can be complex and costly.尽管如此，随着technological advancements, the efficiency and durability of steam turbines have been continuously improved, making them more sustainable and cost-effective.In conclusion, the steam turbine stands as a testament to human ingenuity in energy conversion. Its pivotal role in powering industrial revolution and modern society cannot be overstated. With continuous innovation and improvement, the steam turbine remains a crucial component in our energyinfrastructure, driving us towards a brighter and more sustainable future.。
蒸汽涡轮机英文作文
蒸汽涡轮机英文作文Steam turbines are a type of rotary engine that convert steam energy into mechanical energy. They are widely used in power generation plants, marine propulsion systems, and various industrial applications. The basic principle of a steam turbine involves the expansion ofhigh-pressure steam through a series of stationary nozzles and rotating blades, which in turn causes the rotor to turn and generate mechanical power. Steam turbines offer several advantages, including high efficiency, reliable operation, and the ability to generate large amounts of power. They are commonly used in fossil fuel power plants, nuclear power plants, and renewable energy facilities such as geothermal and solar thermal power plants. Additionally, steam turbines are crucial components in the operation of ships and submarines, where they provide propulsion by rotating the propeller shaft. In industrial settings, steam turbines are utilized in applications such as driving compressors, pumps, and generators. Overall, steam turbines play a significant role in modern society by providing a reliable and efficient source of power generation and mechanical energy.蒸汽涡轮机是一种将蒸汽能转换为机械能的旋转式引擎。
英语作文闪蒸地热发电厂与水利发电区别
英语作文闪蒸地热发电厂与水利发电区别全文共3篇示例，供读者参考篇1Flash steam geothermal power plants and hydroelectric power plants are two different types of renewable energy sources that harness natural resources to generate electricity. While both technologies have their own advantages and benefits, there are also key differences between them in terms of operation, cost, and environmental impact.Flash steam geothermal power plants utilize the heat energy from underground reservoirs of hot water or steam to generate electricity. The process involves drilling wells into the reservoirs and extracting the hot water or steam to the surface. Thehigh-pressure steam is then passed through a turbine to generate electricity. This technology is highly efficient and provides a reliable source of renewable energy.On the other hand, hydroelectric power plants rely on the kinetic energy of flowing water to produce electricity. These plants are typically located near rivers or other bodies of water where a dam can be constructed to create a reservoir of water.The water is released from the reservoir and flows through turbines, which spin and generate electricity. Hydroelectric power plants are one of the oldest and most established forms of renewable energy, providing a steady and consistent source of power.One key difference between flash steam geothermal power plants and hydroelectric power plants is the source of energy they harness. Geothermal power plants use the heat energy from the earth's core, which is a constant and renewable source of energy. In contrast, hydroelectric power plants rely on the water cycle to generate electricity, which can be influenced by factors such as rainfall and snowmelt. While both technologies are renewable, geothermal power plants are more consistent in their energy output.Another difference between the two technologies is the cost of installation and operation. Flash steam geothermal power plants require expensive drilling and infrastructure to access the underground reservoirs of hot water or steam. However, once the plant is operational, the operating costs are relatively low. In comparison, hydroelectric power plants require significant investment in dam construction and turbine technology, but have lower operating costs in the long term.In terms of environmental impact, both flash steam geothermal power plants and hydroelectric power plants are considered to be clean energy sources. Geothermal power plants produce minimal greenhouse gas emissions and have a small footprint on the land. Hydroelectric power plants also have a low carbon footprint, but can have negative effects on the surrounding ecosystem and water quality. Dams can disrupt natural habitats and prevent fish migration, leading to potential environmental concerns.In conclusion, both flash steam geothermal power plants and hydroelectric power plants are valuable sources of renewable energy that play a crucial role in reducing carbon emissions and combatting climate change. While they have distinct differences in terms of energy sources, cost, and environmental impact, both technologies have a place in the transition to a cleaner and more sustainable energy future. By harnessing the power of geothermal and hydro energy, we can create a greener and more resilient energy system for generations to come.篇2Flash steam geothermal power plants and hydroelectric power plants are two different types of renewable energysources that generate electricity. Despite both being environmentally friendly and sustainable, there are several key differences between the two.Flash steam geothermal power plants utilize high-pressure hot water from deep within the Earth to produce steam, which then drives turbines to generate electricity. These power plants are usually located in areas with high geothermal activity, such as geysers or hot springs. In contrast, hydroelectric power plants generate electricity by utilizing moving water to turn turbines. This moving water could come from rivers, dams, or other sources.One major difference between the two is their location and availability. Flash steam geothermal power plants can only be built in areas with high geothermal activity, meaning they are limited to certain regions of the world. Hydroelectric power plants, on the other hand, can be built in many different locations where there is a sufficient water supply. This makes hydroelectric power more accessible and widespread than geothermal power.Another key difference is the environmental impact of the two types of power plants. While both are eco-friendly alternatives to fossil fuel-based power plants, hydroelectricpower plants can have a larger impact on the local ecosystem. The construction of dams can disrupt river habitats and affect fish populations. In contrast, flash steam geothermal power plants have minimal impact on the environment once they are up and running, as they do not require ongoing water usage or produce greenhouse gas emissions.In terms of efficiency, flash steam geothermal power plants are generally more reliable and consistent in their electricity generation compared to hydroelectric power plants. This is because geothermal energy is not affected by weather conditions, while water availability can fluctuate with changing seasons in hydroelectric power plants.In conclusion, flash steam geothermal power plants and hydroelectric power plants are both valuable sources of renewable energy with their own unique benefits and drawbacks. While geothermal power is limited by location, it is a reliable and environmentally friendly option for regions with high geothermal activity. Hydroelectric power, on the other hand, is more widely available but can have a greater impact on the local ecosystem. Both are important contributors to a sustainable energy future and can play a key role in reducing our dependence on fossil fuels.篇3Flash steam geothermal power plants and hydroelectric power plants are two types of renewable energy sources that are utilized for electricity generation. While both of these sources harness the power of water to generate electricity, there are significant differences between the two in terms of their efficiency, environmental impact, and geographical requirements.Flash steam geothermal power plants utilize the heat from deep within the Earth to generate steam, which is then used to drive turbines that produce electricity. This process requires drilling deep into the Earth's crust to access the hot water and steam reservoirs, which are then brought to the surface to generate electricity. In contrast, hydroelectric power plants rely on the gravitational force of flowing water to generate electricity. Water from a reservoir or a river is directed through turbines, which convert the kinetic energy of the water into electricity.One of the key differences between flash steam geothermal power plants and hydroelectric power plants is their efficiency. Geothermal power plants are known for their high efficiency levels, as the heat from the Earth is a consistent and reliable source of energy. In contrast, hydroelectric power plants can beaffected by factors such as droughts and seasonal variations in water flow, which can impact their efficiency and output.Another difference between the two types of power plants is their environmental impact. Geothermal power plants have minimal environmental impact, as they do not release greenhouse gases or other pollutants into the atmosphere. In comparison, hydroelectric power plants can have a significant impact on the surrounding environment, particularly if large dams are constructed. Dams can disrupt natural river ecosystems, alter water flow patterns, and displace wildlife and local communities.In terms of geographical requirements, both types of power plants have specific location needs. Geothermal power plants are typically located in areas with high levels of geothermal activity, such as tectonic plate boundaries or volcanic regions. In contrast, hydroelectric power plants require a reliable source of flowing water, which can be found in rivers, lakes, or reservoirs. The location of a hydroelectric power plant is also influenced by factors such as topography, water flow rates, and environmental considerations.In conclusion, flash steam geothermal power plants and hydroelectric power plants are both valuable sources ofrenewable energy that play a crucial role in the transition to a more sustainable energy future. While both types of power plants harness the power of water to generate electricity, they have distinct differences in terms of efficiency, environmental impact, and geographical requirements. By understanding these differences, policymakers and energy stakeholders can make informed decisions about the most appropriate energy generation mix for their specific needs and goals.。
运用高中物理知识的小发明
运用高中物理知识的小发明Recently, I have been fascinated with the idea of creating small inventions that can utilize my knowledge of high school physics. One idea that I have been contemplating is a mini wind turbine that can generate electricity to power small electronic devices. 近来，我一直着迷于创造能够利用我在高中物理知识的小发明。
我一直在考虑的一个点子是一个可以生成电力以为小型电子设备供电的迷你风力涡轮机。
The concept of harnessing wind energy to produce electricity is not a new one, but the idea of creating a small-scale version that can be easily implemented in daily life is what sets my invention apart. 利用风能来生产电力的概念并不是一个新观念，但是将这个想法放大，创造一个可以在日常生活中轻松实施的小型版本，这是我发明的独特之处。
By using the principles of physics, such as the conversion of mechanical energy into electrical energy, I plan to build a mini wind turbine that can efficiently capture the wind's energy and convert it into electricity. 通过利用物理原理，比如将机械能转化为电能，我计划建造一个小型风力涡轮机，能够高效捕获风力能量并将其转化为电能。
汽轮机阀门制造工艺流程
汽轮机阀门制造工艺流程英文回答：Turbine Valve Manufacturing Process.Turbine valves are critical components in steam turbine engines, controlling the flow of steam and regulating the turbine's operation. The manufacturing process of these valves involves various stages, each requiring precision and stringent quality control. Here is a detailed outline of the turbine valve manufacturing process:1. Design and Engineering.The first step involves designing the valve based on the specific requirements of the steam turbine system. Engineers utilize computer-aided design (CAD) software to create intricate designs that meet the necessary performance and safety standards. Finite element analysis (FEA) is employed to analyze the valve's structuralintegrity and optimize its design.2. Material Selection.The materials used in turbine valve construction are crucial to ensure durability and reliability under extreme operating conditions. Common materials employed include high-grade stainless steels, nickel-based alloys, and hardened metals. The selection of materials depends on factors such as the operating temperature, pressure, and corrosion resistance required.3. Casting and Forging.The body of the valve is typically formed through casting or forging processes. Casting involves pouring molten metal into a mold and allowing it to solidify. Forging, on the other hand, involves shaping the metal by applying compressive forces using a press or hammer. Both methods produce complex shapes with the desired metallurgical properties.4. Machining.Once the valve body is formed, it undergoes precision machining to create the intricate internal surfaces and passages. This involves utilizing various machining techniques, such as milling, drilling, and grinding, to achieve the required dimensions and tolerances. The precision of these machining processes is essential for ensuring the valve's proper functioning and reliability.5. Heat Treatment.Heat treatment processes are applied to improve the mechanical properties of the valve components. Annealing, tempering, and hardening treatments are utilized to enhance the strength, hardness, and toughness of the materials. These processes involve heating and cooling the components under controlled conditions to achieve the desired metallurgical properties.6. Assembly.The individual components of the valve are assembled with meticulous precision. This includes fitting the valve seat, stem, actuator, and other components. The assembly process requires skilled technicians who follow strict procedures to ensure proper alignment and functioning of the valve.7. Testing and Inspection.Rigorous testing and inspection procedures are conducted to verify the valve's performance and integrity. This involves pressure testing, flow rate testing, and non-destructive testing methods such as ultrasonic and radiographic inspection. The valves undergo thorough evaluation to ensure they meet the specified requirements and quality standards.8. Finishing and Packaging.The finished valves are subjected to various finishing processes, such as polishing, painting, or coating, to enhance their appearance and protect them from externalfactors. They are then carefully packaged and stored or shipped to the end-user.9. Installation and Commissioning.The turbine valves are installed in the steam turbine system, typically requiring specialized tools and procedures. After installation, the valves undergo commissioning, which involves testing and adjusting their operation to ensure proper integration with the system.中文回答：汽轮机阀门制造工艺流程。
气尖引擎在真空里的效率
The Efficiency of Gas-Turbine Engines in a VacuumGas-turbine engines, commonly known as jet engines, are designed to operate efficiently in atmospheric conditions, where there is sufficient oxygen for combustion. However, their performance in a vacuum, such as in space, presents a unique challenge.In a vacuum, the absence of air means there is no oxygen for combustion, which is essential for generating thrust in gas-turbine engines. This significantly limits their efficiency and effectiveness. Additionally, the lack of air also affects the cooling and lubrication systems of the engine, potentially leading to overheating and mechanical issues.To overcome these challenges, spacecraft and aircraft designed for vacuum environments often utilize alternative propulsion systems, such as ion engines or rocket engines, which do not rely on atmospheric oxygen for combustion. These systems are specifically designed to operate efficiently in the absence of air, making them more suitable for vacuum environments.In conclusion, while gas-turbine engines are highly efficient in atmospheric conditions, their efficiency in a vacuum is significantly limited due to the absence of oxygen for combustion. Alternative propulsion systems are required for spacecraft and aircraft operating in vacuum environments to ensure optimal performance.气尖引擎在真空里的效率气尖引擎，即我们常说的喷气发动机，是设计来在大气条件下高效运行的，那里有足够的氧气供燃烧使用。
武汉理工大学轮机专业英语备考重点
Lesson 13 Marine Boilers and Their Construction 船用锅炉及其结构A boiler in one form or another will be found on every type of ship. Where the main machinery is steam powered, one or more large water -tube boilers will be fitted to produce steam at very high temperatures and pressures. On a diesel main machinery vessel, a smaller (usually fire tube type) boiler will be fitted to provide steam for the various ship services. Even within the two basic design types, water tube and fire tube. A variety of designs and variations exist.每种类型的船上总会有某种类型的锅炉。
在由蒸汽驱动为主动力装置的船舶上，装有一个或者多个大型水管锅炉用来产生高温高压的蒸汽。
在柴油机做主动力装置的船舶上，通常装有一个小型的(多为火管)锅炉用来产生各种日常用途的蒸汽。
在水管锅炉和火管锅炉这两个基本的形式下有不同的设计形式存在。
A boiler is used to heat feed water in order to produce steam. The energy released by the burning fuel in the boiler furnace is stored (as temperature and pressure) in the steam produced. All boilers have a furnace or combustion chamber where fuel is burnt to release its energy. Air is supplied to the boiler furnace to enable combustion of the fuel to take place. A large surface area between the combustion chamber and the water enables the energy of combustion, in the form of heat, to be transferred to the water.锅炉用来加热炉水从而产生蒸汽。
蒸汽轮机说明书
Steam TurbinesSteam turbines are a mature technology and have been used since the 1880s for electricity production. Most of the electricity generated in the United States is produced by steam turbines integrated in central station power plants. In addition to central station power, steam turbines are also commonly used for combined heat and power (CHP) instal-lations (see Table 1 for summary of CHP attributes). ApplicationsBased on data from the CHP Installation Database,1 there are 699 sites in the United States that are using steam turbines for CHP operation. These steam turbine CHP installations have an average capacity of 37 MW and a combined capacity of 26 GW, representing 32% of the installed CHP capacity in the United States.2 The majority of these CHP steam turbines are used at industrial plants (e.g., paper, chemicals, and food), commercial buildings with high thermal loads(e.g., hospitals), and districtheating sites (e.g., universities).Steam turbines are well suited tomedium- and large-scale indus-trial and institional applicationswhere inexpensive fuels such ascoal, biomass, solid wastes andbyproducts (e.g., wood chips),refinery residual oil, and refineryoff gases are available.TechnologyDescriptionA steam turbine is driven withhigh pressure steam produced bya boiler or heat recovery steamgenerator (HRSG). Unlike gasturbines or microturbines, steamturbines do not directly consumefuel. Rather, the fuel driving theprocess is the fired boiler or plantequipment that produces heat forthe HRSG (e.g., a gas turbine).1 U.S. DOE Combined Heat and Power Installation Database, data compiled throughDecember 31, 2015.2 These statistics only include steam turbines integrated with boilers. The statistics donot include steam turbines driven by steam produced from heat recovery steam genera-tors used in combined cycle CHP systems.ADVANCED MANUFACTURING OFFICESteam turbines operate on the Rankine cycle (see Figure 1). In this thermo-dynamic cycle, water is pumped to high pressure and then heated to generate high pressure steam. The high pressure steam is then expanded through a steam turbine where steam energy is converted to mechanical power that drives an electri-cal generator. For CHP configurations, low pressure steam that exits the steam turbine is then available to satisfy on-site thermal needs. Condensed liquid is then returned to the pump, and the cycle is repeated.Steam turbines for CHPapplications are classified as either non-condensing or extraction. A non-condensing turbine, also referred to as a backpressure turbine (see Figure 2), exhausts steam directly to an industrial process or to a steam distribution system. In a backpressure turbine, common pressure levels are 50, 150, and 250 psig, with lower pressures often used in district heating systems; higher pressures are more typical for industrial processes.An extraction turbine has one or more openings in its casing to extract steam at an intermediate pressure. The extracted steam is then used in CHP configurations that require steam pressures higher than pressures available from backpressure steam turbines.Regardless of steam turbine type – backpressure or extraction – the primary objective of most steam turbine CHP systems is to deliver relatively large amounts of thermal energy, with electric-ity generated as a byproduct of heat generation. Therefore, most steam turbine CHP systems are characterized by low power to heat ratios, often below 0.2.Performance CharacteristicsTable 2 shows performance characteristics for three representative backpressure steam turbines used in CHP applications with electric power capacities of 500 kW, 3 MW, and 15 MW. As indicated, all three systems have overall efficiencies near 80%3 and power to heat ratios of 0.1 or lower. High overall efficiencies and low power to heat ratios are common characteristics for steam turbines configured for CHP applications.Figure 1. Components of a boiler/steam turbine.Figure courtesy of U.S. Department of EnergyFigure 2. Non-condensing (backpressure) steam turbine.Figure courtesy of U.S. Department of EnergyInterior view of steam turbine blades.Photo courtesy of Siemens3 The overall CHP efficiency for a backpressure boiler/steam turbine system is typically slightly lower than the boiler efficiency.Capital and O&M CostsMajor subsystems required for a complete steam turbine CHP plant include a boiler or HRSG, steam loop, and a steam turbine. In addition, a control system is needed and emission reduction hardware may be required depending on local air quality requirements. The steam turbine is just one cost component in a complete CHP plant. As an example, for a steam turbine CHP plant burning solid biomass, the installed cost for the complete CHP plant will be roughly $5,000/kW or higher. The installed cost for the steam turbine and electrical generator will represent approximately 15% to 25% of this total installed cost. These cost estimates are rough guidelines and are only intended to offer a perspective on the relative cost for the turbine/generator components that are integrated into a complete steam turbine CHP installation.Table 3 shows capital costs and opera-tion and maintenance (O&M) costs for three representative backpressure steam turbines. As indicated, installed costs for the turbine/generator range from approximately $670/kW to $1,140/kW, with costs on a per kW basis declining as capacity increases. The turbine/generator costs in Table 3 include the steam turbine, generator, and generator control system. The costs do not include the boiler, steam loop, and controls.Non-fuel O&M costs rangefrom 0.6 to 1.0 ¢/kWh for thethree steam turbines shownin Table 3. Similar to capital costs, there are economies of scale, and the O&M costs decline on a per kWh basis as the steam turbine capacity increases. The O&M costs shown in Table 3 are forthe steam turbine/generator subsystem and do not include O&Mexpenses for the boiler and steam loop.a specific product.4 Manufacturers often express fuel input and efficiency values based on the lower heat -ing value (LHV) of the fuel. All quantities in this fact sheet are expressed based onhigher heating value (HHV) unless noted otherwise. For natural gas, the ratio of LHV to HHV is approximately 0.9.5 Power to heat ratio is the electric power output divided by the useful thermal output.The quantities are expressed in equivalent units, and the ratio is unit-less. 6 Installation and BOP costs estimated at 70% of the turbine/generator capital cost.EmissionsSteam turbine emissions depend on how the steam is generated (e.g., boiler or HRSG) and what type of fuel is used to generate the steam. Table 4 shows NOx, CO, and VOC emissions based on EPA emission fac-tors for boilers that are fired with natural gas and coal. A 500 kW steam turbine utiliz-ing a natural gas fired boiler will have estimated NOx emissions in the range of 26-81 ppm (at 3% oxygen). A larger 15,000 kW CHP steam turbine integrated with a natural gas boiler will have estimated NOx emis-sions in the range of 81-226 ppm (at 3% oxygen). This 15,000 kW steam turbine, if integrated with a coal fired boiler, will have estimated NOx emissions in the range of 141-929 ppm (at 3% oxygen).Table 4 shows CO 2 emis-sions for steam turbineplants based on the electric power output and on thecomplete CHP system. For the complete CHP system, CO 2emissions are calculated with a thermal credit for fuel that would otherwise be used by an on-site boiler. With this credit, CO 2emissions range from 519 to 531 lbs/MWh for natural gas boil -ers, and 935-957 lbs/MWh for coal fired boilers. For compari -son, a typical natural gas combined cycle power plant will haveemissions of 800-900 lbs/MWh, and a coal plant will have CO 2emissions near 2,000 lbs/MWh. product.7 NOx, CO, and VOC emission factors are based on EPA AP-42 values. 8 Emission factors for System #1 are based on boiler input < 100 MMBtu/hr. Emission factors for Systems #2 and #3 are based on boiler input > 100 MMBtu/hr.9 System #1 is relatively small and would typically not be integrated with a coal firedboiler. Emissions for System #1 are only shown for natural gas boiler fuel.10 N Ox, CO, and VOC emissions expressed in units of lbs/MWh are based on electricoutput and do not include a thermal credit.11 N Ox conversion (natural gas): NOx [lbs/MWh] = NOx [ppm @ 3% O2] / 824 / electri -cal efficiency [%, HHV] X 3.412. For coal, use factor of 732 instead of 824.12 C O conversion (natural gas): CO [lbs/MWh] = CO [ppm @ 3% O2] / 1,354 / electrical efficiency [%, HHV] X 3.412. For coal, use factor of 1,203 instead of 1,354.13 V OC conversion (natural gas): VOC [lbs/MWh] = VOC [ppm @ 3% O2] / 2,362 / electrical efficiency [%, HHV] X 3.412. For coal, use factor of 2,099 instead of 2,362.14 T he CHP CO2 emissions include a thermal credit for avoided fuel that would other -wise be used by an onsite boiler.DOE/EE-1334 • July 2016For more information, visit the CHP Deployment Program at /chp *********************.gov。
Turbo system
Turbo Systems 102 (Advanced)Please thoroughly review and have a good understanding of Turbo Systems 101- Basic prior to reading this section. The following areas will be covered in the Turbo System 102 - Advanced section:1. Wheel trim topic coverageTrim is a common term used when talking about or describing turbochargers. For example, you may hear someone say "I have a GT2871R ' 56 Trim ' turbocharger. What is 'Trim?' Trim is a term to express the relationship between the inducer* and exducer* of both turbine and compressor wheels. More accurately, it is an area ratio.* The inducer diameter is defined as the diameter where the air enters the wheel, whereas the exducer diameter is defined as the diameter where the air exits the wheel.Based on aerodynamics and air entry paths, the inducer for a compressor wheel is the smaller diameter. For turbine wheels, the inducer it is the larger diameter (see Figure 1.)Figure 1. Illustration of the inducer and exducer diameter of compressor and turbine wheelsExample #1: GT2871R turbocharger (Garrett part number 743347-2) has a compressor wheel with the below dimensions. What is the trim of the compressor wheel?Inducer diameter = 53.1mmExducer diameter = 71.0mmExample #2: GT2871R turbocharger (part # 743347-1) has a compressor wheel with an exducer diameter of 71.0mm and a trim of 48. What is the inducer diameter of the compressor wheel?Exducer diameter = 71.0mmTrim = 48The trim of a wheel, whether compressor or turbine, affects performance by shifting the airflow capacity. All other factors held constant, a higher trim wheel will flow more than a smaller trim wheel.However, it is important to note that very often all other factors are not held constant. So just because a wheel isa larger trim does not necessarily mean that it will flow more.2. Understanding housing sizing: A/RA/R (Area/Radius) describes a geometric characteristic of all compressor and turbine housings. Technically, it is defined as:the inlet (or, for compressor housings, the discharge) cross-sectional area divided by the radius from the turbo centerline to the centroid of that area (see Figure 2.).Figure 2. Illustration of compressor housing showing A/R characteristicThe A/R parameter has different effects on the compressor and turbine performance, as outlined below.Compressor A/R - Compressor performance is comparatively insensitive to changes in A/R. Larger A/R housings are sometimes used to optimize performance of low boost applications, and smaller A/R are used for high boost applications. However, as this influence of A/R on compressor performance is minor, there are not A/R options available for compressor housings.Turbine A/R - Turbine performance is greatly affected by changing the A/R of the housing, as it is used to adjust the flow capacity of the turbine. Using a smaller A/R will increase the exhaust gas velocity into the turbine wheel. This provides increased turbine power at lower engine speeds, resulting in a quicker boost rise. However, a small A/R also causes the flow to enter the wheel more tangentially, which reduces the ultimate flow capacity of the turbine wheel. This will tend to increase exhaust backpressure and hence reduce the engine's ability to "breathe" effectively at high RPM, adversely affecting peak engine power.Conversely, using a larger A/R will lower exhaust gas velocity, and delay boost rise. The flow in a larger A/R housing enters the wheel in a more radial fashion, increasing the wheel's effective flow capacity, resulting in lower backpressure and better power at higher engine speeds.When deciding between A/R options, be realistic with the intended vehicle use and use the A/R to bias the performance toward the desired powerband characteristic.Here's a simplistic look at comparing turbine housing geometry with different applications. By comparing different turbine housing A/R, it is often possible to determine the intended use of the system.Imagine two 3.5L engines both using GT30R turbochargers. The only difference between the two engines is a different turbine housing A/R; otherwise the two engines are identical:1. Engine #1 has turbine housing with an A/R of 0.632. Engine #2 has a turbine housing with an A/R of 1.06.What can we infer about the intended use and the turbocharger matching for each engine?Engine#1: This engine is using a smaller A/R turbine housing (0.63) thus biased more towards low-end torque and optimal boost response. Many would describe this as being more "fun" to drive on the street, as normal daily driving habits tend to favor transient response. However, at higher engine speeds, this smaller A/R housing will result in high backpressure, which can result in a loss of top end power. This type of engine performance isdesirable for street applications where the low speed boost response and transient conditions are more important than top end power.Engine #2: This engine is using a larger A/R turbine housing (1.06) and is biased towards peak horsepower, while sacrificing transient response and torque at very low engine speeds. The larger A/R turbine housing will continue to minimize backpressure at high rpm, to the benefit of engine peak power. On the other hand, this will also raise the engine speed at which the turbo can provide boost, increasing time to boost. The performance of Engine #2 is more desirable for racing applications than Engine #1 where the engine will be operating at high engine speeds most of the time.3. Different types of manifolds (advantages/disadvantages log style vs. equal length)There are two different types of turbocharger manifolds; cast log style (see Figure 3.) and welded tubular style (see Figure 4.).Figure 3. Cast log style turbocharger manifoldFigure 4. Welded tubular turbocharger manifoldManifold design on turbocharged applications is deceptively complex as there many factors to take into account and trade offGeneral design tips for best overall performance are to:•Maximize the radius of the bends that make up the exhaust primaries to maintain pulse energy •Make the exhaust primaries equal length to balance exhaust reversion across all cylinders•Avoid rapid area changes to maintain pulse energy to the turbine•At the collector, introduce flow from all runners at a narrow angle to minimize "turning" of the flow in the collector•For better boost response, minimize the exhaust volume between the exhaust ports and the turbine inlet•For best power, tuned primary lengths can be usedCast manifolds are commonly found on OEM applications, whereas welded tubular manifolds are found almost exclusively on aftermarket and race applications. Both manifold types have their advantages and disadvantages. Cast manifolds are generally very durable and are usually dedicated to one application. They require special tooling for the casting and machining of specific features on the manifold. This tooling can be expensive.On the other hand, welded tubular manifolds can be custom-made for a specific application without special tooling requirements. The manufacturer typically cuts pre-bent steel U-bends into the desired geometry and then welds all of the components together. Welded tubular manifolds are a very effective solution. One item of note is durability of this design. Because of the welded joints, thinner wall sections, and reduced stiffness, these types of manifolds are often susceptible to cracking due to thermal expansion/contraction and vibration. Properly constructed tubular manifolds can last a long time, however. In addition, tubular manifolds can offer a substantial performance advantage over a log-type manifold.A design feature that can be common to both manifold types is a " DIVIDED MANIFOLD" , typically employed with " DIVIDED " or "twin-scroll" turbine housings. Divided exhaust manifolds can be incorporated into either a cast or welded tubular manifolds (see Figure 5. and Figure 6.).Figure 5. Cast manifold with a divided turbine inlet design featureFigure 6. Welded tubular manifold with a divided turbine inlet design featureThe concept is to DIVIDE or separate the cylinders whose cycles interfere with one another to best utilize the engine's exhaust pulse energy.For example, on a four-cylinder engine with firing order 1-3-4-2, cylinder #1 is ending its expansion stroke and opening its exhaust valve while cylinder #2 still has its exhaust valve open (cylinder #2 is in its overlap period). In an undivided exhaust manifold, this pressure pulse from cylinder #1's exhaust blowdown event is much more likely to contaminate cylinder #2 with high pressure exhaust gas. Not only does this hurt cylinder #2's ability to breathe properly, but this pulse energy would have been better utilized in the turbine.The proper grouping for this engine is to keep complementary cylinders grouped together-- #1 and #4 are complementary; as are cylinders #2 and #3.Figure 7. Illustration of divided turbine housingBecause of the better utilization of the exhaust pulse energy, the turbine's performance is improved and boost increases more quickly.4. Compression ratio with boostBefore discussing compression ratio and boost, it is important to understand engine knock, also known as detonation. Knock is a dangerous condition caused by uncontrolled combustion of the air/fuel mixture. This abnormal combustion causes rapid spikes in cylinder pressure which can result in engine damage.Three primary factors that influence engine knock are:1.Knock resistance characteristics (knock limit) of the engine: Since every engine is vastlydifferent when it comes to knock resistance, there is no single answer to "how much." Design features such as combustion chamber geometry, spark plug location, bore size and compression ratio all affect the knock characteristics of an engine.2.Ambient air conditions: For the turbocharger application, both ambient air conditions and engine inletconditions affect maximum boost. Hot air and high cylinder pressure increases the tendency of an engine to knock. When an engine is boosted, the intake air temperature increases, thus increasing the tendency to knock. Charge air cooling (e.g. an intercooler) addresses this concern by cooling the compressed air produced by the turbocharger3.Octane rating of the fuel being used: octane is a measure of a fuel's ability to resist knock. Theoctane rating for pump gas ranges from 85 to 94, while racing fuel would be well above 100. The higher the octane rating of the fuel, the more resistant to knock. Since knock can be damaging to an engine, it isimportant to use fuel of sufficient octane for the application. Generally speaking, the more boost run, the higher the octane requirement.This cannot be overstated: engine calibration of fuel and spark plays an enormous role in dictating knock behavior of an engine. See Section 5 below for more details.Now that we have introduced knock/detonation, contributing factors and ways to decrease the likelihood of detonation, let's talk about compression ratio. Compression ratio is defined as:orwhereCR = compression ratioV d = displacement volumeV cv = clearance volumeThe compression ratio from the factory will be different for naturally aspirated engines and boosted engines. For example, a stock Honda S2000 has a compression ratio of 11.1:1, whereas a turbocharged Subaru Impreza WRX has a compression ratio of 8.0:1.There are numerous factors that affect the maximum allowable compression ratio. There is no single correct answer for every application. Generally, compression ratio should be set as high as feasible without encountering detonation at the maximum load condition. Compression ratio that is too low will result in an engine that is a bit sluggish in off-boost operation. However, if it is too high this can lead to serious knock-related engine problems.Factors that influence the compression ratio include: fuel anti-knock properties (octane rating), boost pressure, intake air temperature, combustion chamber design, ignition timing, valve events, and exhaust backpressure. Many modern normally-aspirated engines have well-designed combustion chambers that, with appropriate tuning, will allow modest boost levels with no change to compression ratio. For higher power targets with more boost , compression ratio should be adjusted to compensate.There are a handful of ways to reduce compression ratio, some better than others. Least desirable is adding a spacer between the block and the head. These spacers reduce the amount a "quench" designed into an engine's combustion chambers, and can alter cam timing as well. Spacers are, however, relatively simple and inexpensive.A better option, if more expensive and time-consuming to install, is to use lower-compression pistons. These will have no adverse effects on cam timing or the head's ability to seal, and allow proper quench regions in the combustion chambers.5. Air/Fuel Ratio tuning: Rich v. Lean, why lean makes more power but is more dangerousWhen discussing engine tuning the 'Air/Fuel Ratio' (AFR) is one of the main topics. Proper AFR calibration is critical to performance and durability of the engine and it's components. The AFR defines the ratio of the amount of air consumed by the engine compared to the amount of fuel.A 'Stoichiometric' AFR has the correct amount of air and fuel to produce a chemically complete combustion event. For gasoline engines, the stoichiometric , A/F ratio is 14.7:1, which means 14.7 parts of air to one part of fuel. The stoichiometric AFR depends on fuel type-- for alcohol it is 6.4:1 and 14.5:1 for diesel.So what is meant by a rich or lean AFR? A lower AFR number contains less air than the 14.7:1 stoichiometric AFR, therefore it is a richer mixture. Conversely, a higher AFR number contains more air and therefore it is a leaner mixture.For Example:15.0:1 = Lean14.7:1 = Stoichiometric13.0:1 = RichLeaner AFR results in higher temperatures as the mixture is combusted. Generally, normally-aspirated spark-ignition (SI) gasoline engines produce maximum power just slightly rich of stoichiometric. However, in practice it is kept between 12:1 and 13:1 in order to keep exhaust gas temperatures in check and to account for variances in fuel quality. This is a realistic full-load AFR on a normally-aspirated engine but can be dangerously lean with a highly-boosted engine.Let's take a closer look. As the air-fuel mixture is ignited by the spark plug, a flame front propagates from the spark plug. The now-burning mixture raises the cylinder pressure and temperature, peaking at some point in the combustion process.The turbocharger increases the density of the air resulting in a denser mixture. The denser mixture raises the peak cylinder pressure, therefore increasing the probability of knock. As the AFR is leaned out, the temperatureof the burning gases increases, which also increases the probability of knock. This is why it is imperative to run richer AFR on a boosted engine at full load. Doing so will reduce the likelihood of knock, and will also keep temperatures under control.There are actually three ways to reduce the probability of knock at full load on a turbocharged engine: reduce boost, adjust the AFR to richer mixture, and retard ignition timing. These three parameters need to be optimized together to yield the highest reliable power.For further in-depth calculations of pressure ratio, mass flow, and turbocharger selection, please readtutorial.。
- 1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。
A High-efficiency Steam Turbine Utilizing Optimized Reaction Blades 104A High-efficiency Steam Turbine Utilizing OptimizedReaction Blades — An Application to the Kwangyang Combined-cyclePower Plant of K-Power of Republic of Korea —Hidetoshi Fujii T etsuaki Kimura Kiyoshi SegawaINTRODUCTIONAS regards thermal power generation in recent years,to reduce carbon-dioxide emissions and fuel consumption from the viewpoint of environmental protection, the need to improve the efficiency of power plants has been growing ever stronger. In particular,in the case of steam turbines, improvement of thermal efficiency has become vital.Aiming to attain high efficiency, Hitachi, Ltd. has been developing rotor blades for the steam turbines of thermal power plants. As for the relatively short rotor blades (i.e. small blade height) applied in the high-OVERVIEW: In recent years, since reduction of carbon-dioxide emissions is drawing major attention, new thermal power plants — the main body ofwhich are destined for overseas markets — demand improved thermal efficiency even in the case of steam turbines. At the same time, in regard to rotor blades (which have relatively small blade length), the role of aerodynamic loss in the secondary flow regions and in the boundary layers along the blade length becomes significant; therefore, Hitachi developed an optimized reaction blade based on a new design concept that takes such steam flow characteristics into account. Applied in the high-pressure-turbine sections of two steam turbines for combined-cycle power generators hitherto used for 50-Hz generation, these blades significantly improve the efficiency of the high-pressure turbines. The optimized reaction blades were installed in the high-pressure turbines of the Kwangyang Combined-cycle Power Plant (steam-turbine output power: 200 MW) of K-Power of Republic of Korea. It was confirmed by performance testing on actual turbines that in this first application to 60-Hz turbines, these blades significantly improve turbine efficiency in a similar manner to the 50-Hz applications so far practically implemented.Fig. 1—High-pressure Turbine Unit of the 200-MW Steam Turbine for the Kwangyang Combined-cycle Power Plant of Republic of Korea’s K-Power.The high-pressure turbine rotor is integrated in the lower half of the turbine casing, and the high-pressure turbine adopts optimized reaction blades(newly developed by Hitachi) for allturbine stages.characteristics.pressure section of a 200–300-MW-class steam turbine for combined-cycle power generation, and a significant improvement in efficiency was confirmed by performance tests.Focusing on the turbine for the Kwangyang Combined-cycle Power Plant of Korea’s K-Power, this report describes the newly developed optimized reaction blades (hereafter abbreviate as HX blades) for a high-pressure turbine (see Fig. 1). DEVELOPMENT OF HX BLADES Development StrategyAs for improving internal efficiency of high-pressure steam turbines, small root diameter and a large number of stages is effective. Accordingly, for turbines whose steam-path design adopts various measures for improving internal efficiency, optimization calculations with parameters such as stage number, blade root diameter, and root reaction are executed, and optimum points are thereby obtained (see Fig. 2). Moreover, as for this steam-path design, various loss models (e.g. profile loss and secondary loss) based on the results of flow analysis and experimental tests are incorporated. As for the rotor blades developed in the present work, the combination of stage number and root reaction that gives the highest turbine efficiency is obtained, and this result was taken as the design conditions for the developed blade.The turbine that exploits the optimized steam path possesses a higher degree of reaction in comparison with the high- and intermediate-pressure steam turbines introduced by Hitachi up till now. The design of the new rotor blades applied in this turbine is described in the following.The HX blade that we have newly developed has two characteristic features: first, it is applied in the high-pressure turbine section and, second, because the application profile (i.e. cross-sectional shape) is sectioned in accordance with blade height, a further optimized blade profile is applicable from the viewpoint of performance concerning each stage of the turbine.The application region of each blade profile is separated into two types according to steam flow characteristics as follows.Region 1: Blade height is small, and loss at end walls becomes dominant.Region 2: Blade height is comparatively large, and the influence of loss at end walls is low.Two versions of the HX blades were developed as blades optimized for the flow in each region.Based on the highly loaded blades developed by Hitachi and applied on numerous actual turbines so far, the HX blades for region 2 are modified types that improve root reaction from the viewpoint of attaining high efficiency.In the following, an overview of the development of the HX blades applied in region 1 is given. Overview of Development of HX Blades As mentioned above, in regard to the stages in which blade height is low and loss at end walls becomes dominant, the HX blades for region 1 (hereafter just HX blades) are applied.Velocity triangles for the blade inlets are shown in Fig. 3. According to the peripheral velocity of the rotating blade, steam at the absolute velocity at the stationary-blade outlet flows into the rotor blade at the relative velocity as shown in the figure (inflow angle β1). It is clear from Fig. 4 that the profile loss The horizontal axis shows number of stages; the vertical axis shows root reaction. The contour lines represent the distribution of turbine efficiency, and it is clear that peaks of efficiency exist at certain combinations of stage number and root reaction.A High-efficiency Steam Turbine Utilizing Optimized Reaction Blades 106In particular, regarding region 1, since the boundary layer and secondary flow region become dominant in the direction of blade height, inlet flow angle β1 for an actual flow is distributed across a wide range. As for a conventional blade profile, loss characteristics are sensitive to inlet flow angle, so it is necessary to develop a new rotor blade profile with the property that loss varies little even over a wide range of inlet flow angles.Given the above requirement, in regard to the development of the HX blade, we adopted a design of experiments to develop a new blade whose loss characteristic is “robust ” against variation in inlet flow angle.The shape of the newly designed HX blade is shown alongside that of a conventional blade in Fig. 5. The design of the HX blade was optimized by “design of experiments ” and CFD (computational fluid dynamics), and in comparison to the inlet region of the conventional blade, that of the HX blade is significantly blunted.To investigate the two-dimensional blade profile loss, a two-dimensional cascade wind tunnel was used,and energy-loss coefficient was calculated from five-hole pitot-tube traverse measurements. The correlation between energy-loss coefficient ζ and inlet-flow angle β1 is plotted in Fig. 6. The HX blade shows an approximately constant loss coefficient across a wide range of inlet-flow angles from 40° to 80°, and the level of loss coefficient is lower than that of the conventional blade for the whole range of inlet angles.Finally, to evaluate the turbine performance in the case that the HX blades were applied to turbine stages,increases as the direction of the relative velocity deviates from the inlet mechanical angle (βm ) of the rotating blade. In the case of a conventional blade profile, it is a problem that loss characteristics are particularly sensitive to inlet flow angle β1, so a design that reduces the deviation between angles β1 and βm is necessary. In practice, however, the influences of the boundary layer and secondary flow must be taken into account, and it is difficult to accurately predict the relative inlet angle for a rotor blade during the design stage.Fig. 3—Velocity Triangles.As for conventional rotor blades, the design must match design points and blade inlet angles as much as possible.Fig. 4—Profile-loss Characteristics.For a rotating blade with low blade height, it is necessary to develop a blade with the characteristic that its loss does not become large across a wide range of inlet flow angles.Fig. 5—Comparison of Profiles of Conventional Blade and HX Blade.The HX blade has a blunted inlet section (i.e. a “blunted nose”)in comparison with the conventional blade.Conventional blade HX bladeHitachi Review Vol. 56 (2007), No. 4 107model turbine tests were performed.The turbine stage efficiencies of the HX blade and a conventional blade (obtained by a single-stage air-turbine tests) are compared in Fig. 7. It is clear from the figure that in comparison with the efficiency of the conventional blade, that of the HX blade is improved by about 1.5% at all design points. However,if excluding the influences of leakage flow (due to differences in degrees of reaction of rotary-blade edges and seal constructions in the two cases) , the HX bladeimproves stage efficiency by 3%, simply by changing blade configuration.APPLICATION TO ACTUAL TURBINES Application of HX Blade in Actual T urbinesUp till now, the HX blade developed in this work has been applied in a total of four actual steam turbines for combined-cycle power generation at three power companies (namely, one 381-MW-output-power turbine at Spalding Energy Co., Ltd. of the UK, one 250-MW turbine at the Egyptian Electricity Holding Company of Arab Republic of Egypt, and two 200-MW turbines at K-Power of Republic of Korea), and all these turbines have started commercial operation and are continuing to operate smoothly.As one of these examples of application to an actual turbine, the 200-MW steam turbine for the Kwangyang Combined-cycle Power Plant of K-Power of Republic of Korea — the first 60-Hz turbine incorporating theFig. 7—Comparison of Stage Efficiency of Conventional and HX Blades.Deviation (%) of stage efficiency at design points ofconventional blade (on the vertical axis) and root-reaction ratio (on horizontal axis) is shown. The HX blades achieve animprovement in efficiency of more than 1% in comparison withthe conventional blades.Fig. 6—Comparison of Inlet Flow Angle Characteristics of Conventional and HX Blades.The HX blade has an approximately stable loss coefficient across a wide range of inlet flow angles, and it shows a losscoefficient at a lower level than that of the conventional blade.Fig. 8—External View of the High-pressure Turbine Rotor in the Steam Turbine of a Combined-cycle Power Plant.The high pressure section of the steam turbine for theKwangyang Combined-cycle Power Plant is composed of 16turbine stages.A High-efficiency Steam Turbine Utilizing Optimized Reaction Blades 108 ABOUT THE AUTHORSHidetoshi FujiiJoined Hitachi, Ltd. in 1997, and now works at the Steam Turbine Design Section, the Turbine Plant Design Department, Hitachi Works, the Power Systems. He is currently engaged in thermal engineering of steam turbines.Tetsuaki KimuraJoined Hitachi, Ltd. in 1996, and now works at the Steam Turbine Design Section, the Turbine Plant Design Department, Hitachi Works, the Power Systems. He is currently engaged in thermal engineering of steam turbines.Kiyoshi SegawaJoined Hitachi, Ltd. in 1990, and now works at theSteam Turbine Group, the Steam Turbine Project,the Power & Industrial Systems R&D Laboratory,the Power Systems. He is currently engaged in theresearch and development of steam turbines.Mr. Segawa is a member of the Japan Society ofMechanical Engineers (JSME). CONCLUSIONSFocusing on the turbines of the Kwangyang Combined-cycle Power Plant of K-Power in Republic of Korea, this report described the newly developed HX blades for these high-pressure turbines.With an optimum blade profile obtained through a different approach from that for conventional blades, these blades — used particularly for the turbine stages with short blades — significantly improve efficiency compared to the case of conventional blades and, thus, can respond to the efficiency improvements that the market presently demands.Hitachi, Ltd. will from now onwards strive to widely apply these HX blades in actual turbines in power plants both domestically and internationally.REFERENCES(1)K. Segawa et al., “Development of a Highly Loaded RotorBlade for Steam Turbines (2nd Report, Performance Verification), ” JSME International Journal, Series B, 45, No.4 (2002).(2)K. Segawa et al., “A High Performance Optimized ReactionBlade for High Pressure Steam Turbines,” ASME POWER2004 (Mar. 2004). HX blades — is presented in the following.Kwangyang Combined-cycle Power PlantThe two steam turbines at the KwangyangCombined-cycle Power Plant of K-Power of Republicof Korea (each with a rated output power of 200 MW)were the first to adopt Hitachi’s HX blades, and No. 1unit started commercial operation in February 2006,and No. 2 unit started the following May.An overhead view of one of the high-pressureturbines is shown in Fig. 8. This turbine is constructedwith the high- and intermediate-pressure sections in aseparated casing, and the high-pressure turbine isconfigured with a total of 16 stages.As mentioned above, since the high-pressureturbine adopts the HX blades (whose design isoptimized in response to flow characteristics), theperformance of the turbine in its entirety is improved.As regards certified performance tests of this highpressure turbine with HX blades performed beforedelivery to the customer, the certified performance (i.e.turbine efficiency) was satisfactory; that is, it surpassed0.8%.。