汽轮机培训教材S.T.training textbook

尼日利亚大华电厂汽轮机培训教材
Turbine Training Textbook
for Dahua Power Plant, Nigeria
（中英文对照版）
English-Chinese version
大华电厂
Dahua Power Plant
2019.6.12
1、什么叫真空？
当容器中的压力低于大气压力时，把低于大气压力的部分叫真空。

What is vacuum?
When the pressure in the vessel is lower than the atmospheric pressure, the part below the atmospheric pressure is called vacuum.
2、何谓换热？换热有哪几种基本形式？
物体间的热量交换称为换热。

换热有三种基本形式：导热、对流换热、辐射换热。

What is heat transfer? What are the basic forms of heat transfer?
The heat exchange between objects is called heat exchange.
There are three basic forms of heat transfer: heat conduction, convection and radiation.
3、何谓水锤？
在压力管路中，由于液体流速的急剧变化，从而造成管中的液体压力显著、反复、迅速地变化，对管道中有一种“锤击”的特征，这种现象称为水锤（或叫水击）。

What is water hammer?
In the pressure pipeline, because of the rapid change of liquid velocity, the liquid pressure in the pipeline changes significantly, repeatedly and rapidly. There is a characteristic of "hammering" in the pipeline. This phenomenon is called water hammer (or water hammer).
4、汽轮机工作的基本原理是怎样的？
具有一定压力、温度的蒸汽，进入汽轮机，流过喷嘴并在喷嘴内膨胀获得很高的速度。

高速流动的蒸汽流经汽轮机转子上的动叶片做功，当动叶片为反动式时，蒸汽在动叶中发生膨胀产生的反动力亦使动叶片做功，动叶带动汽轮机转子，按一定的速度均匀转动。

这就是汽轮机最基本的工作原理。

What are the basic principles of steam turbine operation?
Steam with certain pressure and temperature enters the steam turbine, flows through the nozzle and expands in the nozzle to achieve high speed. High-speed steam flows through the rotor blade of a steam turbine to do work. When the moving blade is reactionary, the reaction force caused by the expansion of steam in the rotor blade also causes the moving blade to do work, and the moving blade drives the turbine rotor to rotate uniformly at a certain speed. This is the basic working principle of steam turbine.
5、汽轮机本体主要由哪几个部分组成？
汽轮机本体主要由以下几个部分组成：
⑴转动部分：由主轴、叶轮、轴封和安装在叶轮上的动叶片及联轴器等组成。

⑵固定部分：由喷嘴室汽缸、隔板、静叶片、汽封等组成。

⑶控制部分：由调节系统、保护装置和油系统等组成。

What are the main components of the turbine body?
The steam turbine body is mainly composed of the following parts:
(1) Rotating part: It is composed of main shaft, impeller, shaft seal, movable blade and coupling installed on impeller.
(2) Fixed part: composed of nozzle chamber cylinder, baffle, static blade, steam seal, etc.
(3) Control part: It consists of regulation system, protection device and oil system.
6、汽缸的作用是什么？
汽缸是汽轮机的外壳。

汽缸的作用主要是将汽轮机的通流部分（喷嘴、隔板、转子等）与大气隔开，保证蒸汽在汽轮机内完成做功过程。

此外，它还支承汽轮机的某些静止部件（隔板、喷嘴室、汽封套等），承受它们的重量，还要承受由于沿汽缸轴向、径向温度分布不均而产生的热应力。

What is the function of cylinder?
The cylinder is the casing of the steam turbine. The main function of the cylinder is to separate the flow passage (nozzle, diaphragm, rotor, etc.) of the steam turbine from the atmosphere, so as to ensure that the steam can complete the work process in the steam turbine. In addition, it supports some stationary components of steam turbine (diaphragm, nozzle chamber, steam seal sleeve, etc.), bears their weight, and also bears thermal stress due to uneven distribution of temperature along the axial and radial direction of the cylinder.
7、为什么排汽缸要装喷水降温装置？(our seytem have no this device)
在汽轮机起动、空载及低负荷时，蒸汽流通量很小，不足以带走蒸汽与叶轮摩擦产生的热量，从而引起排汽温度升高，排汽缸温度也高。

排汽温度过高会引起排汽缸较大的变形，破坏汽轮机动静部分中心线的一致性，严重时会引起机组振动或其它事故，所以机组一般都装有排汽缸喷水降温装置。

Why is the exhaust cylinder equipped with water spray cooling device? (our seytem has no this device)
When the steam turbine starts, no-load and low load, the steam flow is very small, which is not enough to take away the heat generated by friction between steam and impeller, thus causing the exhaust temperature to rise and the exhaust cylinder temperature to rise. Excessive exhaust temperature will cause large deformation of the exhaust cylinder, destroy the consistency of the center line of the static part of the steam turbine, and cause vibration or other accidents when it is serious, so the units are generally equipped with exhaust cylinder water-jet cooling device.
8、汽轮机喷嘴、隔板、静叶的定义是什么？
喷嘴是由两个相邻静叶片构成的不动汽道，是一个把蒸汽的热能转变为动能的结构元件。

装在汽轮机第一级前的喷嘴成若干组，每组由一个调节汽门控制。

隔板是汽轮机各级的间壁，用以固定静叶片。

静叶是指固定在隔板上静止不动的叶片。

What are the definitions of turbine nozzle, baffle and stator blade?
The nozzle is a fixed passage composed of two adjacent static blades. It is a structural element that converts the heat energy of steam into kinetic energy. The nozzles installed in front of the first stage of the steam turbine are divided into several groups, each group is controlled by a regulating valve.
Diaphragm is the wall of all levels of steam turbine, which is used to fix static blades.
Static blade is a static blade fixed on a baffle.
9、什么是汽轮机的转子？转子的作用是什么？
汽轮机中所有转动部件的组合叫做转子。

转子的作用是承受蒸汽对所有工作叶片的回转力，并带动发电机转子、主油泵和调速器转动。

What is the rotor of a steam turbine? What is the role of the rotor?
The combination of all rotating parts in a steam turbine is called a rotor.
The role of the rotor is to withstand the rotating force of steam on all working blades, and to drive the rotation of the generator rotor, the main oil pump and the governor.
10、叶轮的作用的什么？叶轮是由哪几部分组成的？
叶轮的作用是用来装置叶片，并将汽流力在叶栅上产生的扭矩传递给主轴。

汽轮机叶轮一般由轮缘、轮面和轮毂几部分组成。

What is the function of impeller? What parts are impellers made up of?
The role of the impeller is to install the blade and transfer the torque generated by the steam flow force on the cascade to the spindle.
Turbine impeller is generally composed of rim, wheel surface and hub.
11、叶轮上开平衡孔的作用是什么？
叶轮上开平衡孔是为了减小叶轮两侧蒸汽压差，减小转子产生过大的轴向力。

但在调节级和反动度较大、负载很重的低压部分最末一、二级，一般不开平衡孔，以使叶轮强度不致削弱，并可减少漏汽损失。

What is the role of balancing holes in impellers?
The balancing holes on the impeller are designed to reduce the steam pressure difference between the two sides of the impeller and reduce the excessive axial force produced by the rotor. But in the last first and second stages of the low-pressure part with large adjusting stage and reactivity and heavy load, balancing holes are generally not opened so that the strength of the impeller is not weakened and the leakage loss can be reduced.
12、防止叶片振动断裂的措施主要有哪几点？
防止叶片振动断裂的措施有：
⑴提高叶片、围带、拉金的材料、加工与装配质量。

⑵采取叶片调频措施，避开危险共振范围。

⑶避免长期低频率运行。

What are the main measures to prevent blade vibration fracture?
Measures to prevent blade vibration fracture are as follows:
(1) Improve the material, processing and assembly quality of blade, girdle and bronze.
(2)Take blade frequency modulation measures to avoid dangerous resonance range.
(3) Avoid long-term low frequency operation.
13、汽封的作用是什么？
为了避免动、静部件之间的碰撞，必须留有适当的间隙，这些间隙的存在势必导致漏汽，为此必须加装密封装置——汽封。

根据汽封在汽轮机中所处位置可分为：轴端汽封（简称轴封）、隔板汽封和围带汽封（通流部分汽封）三类。

What is the function of the steam seal?
In order to avoid collision between dynamic and static components, proper clearances must be left. The existence of these clearances will inevitably lead to leakage of steam. Therefore, a sealing device, steam seal, must be installed. According to the position of steam seal in steam turbine, it can be divided into three categories: shaft end seal (abbreviated as shaft seal), diaphragm seal and enclosure seal (through-flow part seal).
14、轴封的作用是什么？
轴封是汽封的一种。

汽轮机轴封的作用是阻止汽缸内的蒸汽向外漏泄，低压缸排汽侧轴封是防止外界空气漏入汽缸。

What is the function of the shaft seal?
Shaft seal is a kind of steam seal. The function of the steam turbine shaft seal is to prevent the steam in the cylinder from leaking out. The side seal of the exhaust steam of the low pressure cylinder is to prevent the outside air from leaking into the cylinder.
15、汽轮机为什么要设滑销系统？
汽轮机在起动及带负荷过程中，汽缸的温度变化很大，因而热膨胀值较大。

为保证汽缸受热时能沿给定的方向自由膨胀，保持汽缸与转子中心一致，同样，汽轮机停机时，保证汽缸能按给定的方向自由收缩，汽轮机均设有滑销系统。

Why should a sliding pin system be installed in a steam turbine?
During the start-up and load-carrying process of steam turbine, the temperature of cylinder varies greatly, so the thermal expansion value is larger. In order to ensure that the cylinder expands freely in a given direction when heated and keeps the cylinder consistent with the center of the rotor, similarly, when the turbine shuts down, the cylinder can shrink freely in a given direction, and the turbine has sliding pin system.
16、汽轮机的盘车装置起什么作用？
汽轮机冲动转子前或停机后，进入或积存在汽缸内的蒸汽使上缸温度比下缸温度高，从而使转子不均匀受热或冷却，产生弯曲变形。

因而在冲转前和停机后，必须使转子以一定的速度连续转动，以保证其均匀受热或冷却。

换句话说，冲转前和停机后盘车可以消除转子热弯曲。

同时还有减小上下汽缸的温差和减少冲转力矩的功用，还可在起动前检查汽轮机动静之间是否有摩擦及润滑系统工作是否正常。

What is the role of the turbine's turning gear?
Steam entering or accumulated in the cylinder makes the temperature of the upper cylinder higher than that of the lower cylinder before or after the impulse rotor of the steam turbine is shut down, so that the rotor is not uniformly heated or cooled, resulting in bending deformation. Therefore, before and after the shutdown, the rotor must rotate continuously at a certain speed to ensure its uniform heating or cooling. In other words, the hot bending of the rotor can be eliminated by turning the car before and after the shutdown. At the same time, it can also reduce the temperature difference between the upper and lower cylinders and the impulse torque. It can also check whether there is friction between the static and dynamic of the steam turbine before starting and whether the lubrication system works properly.
17、轴承的润滑油膜是怎样形成的？
轴瓦的孔径较轴颈稍大些，静止时，轴颈位于轴瓦下部直接与轴瓦内表面接触，在轴瓦与轴颈之间形成了楔形间隙。

当转子开始转动时，轴颈与轴瓦之间会出现直接摩擦。

但是，随着轴颈的转动，润滑油由于粘性而附着在轴的表面上，被带入轴颈与轴瓦之间的楔形间隙中。

随着转速的升高，被带入的油量增多，由于楔形间隙中油流的出口面积不断减小，所以油压不断升高，当这个压力增大到足以平衡转子对轴瓦的全部作用力时，轴颈被油膜托起，悬浮在油膜上转动，从而避免了金属直接摩擦，建立了液体摩擦。

How does the lubricating film of bearings form?
The diameter of bearing bush is slightly larger than that of journal. At rest, the journal is located at the lower part of the bearing bush and contacts directly with the inner surface of the bearing bush, forming a wedge gap between the bearing
bush and the journal.
When the rotor starts to rotate, there will be direct friction between the journal and bearing bush. However, as the Journal rotates, the lubricant adheres to the surface of the shaft due to its viscous property and is brought into the wedge gap between the journal and the bearing bush. With the increase of rotational speed, the amount of oil brought in increases. Because the outlet area of oil flow in wedge clearance decreases continuously, the oil pressure increases continuously. When the pressure increases enough to balance the whole force of the rotor on the bearing bush, the journal is supported by the oil film and suspended to rotate on the oil film, thus avoiding direct metal friction. The liquid friction was established.
18、推力轴承的作用是什么？
推力轴承的作用是承受转子在运行中的轴向推力，确定和保持汽轮机转子和汽缸之间的轴向相互位置。

What is the role of thrust bearings?
The role of thrust bearing is to bear the axial thrust of the rotor in operation and to determine and maintain the axial mutual position between the turbine rotor and the cylinder.
19、汽轮机油系统的作用是什么？
汽轮机油系统的作用如下：
⑴向机组各轴承供油，以便润滑和冷却轴承。

⑵供给调节系统和保护装置稳定充足的压力油，使它们正常工作。

⑶供应各传动机构润滑用油。

What is the role of turbine oil system?
The functions of the turbine oil system are as follows:
(1) Oil is supplied to the bearings of the unit for lubrication and cooling.
(2) Supply sufficient pressure oil to regulate system and protective device to make them work normally.
(3) Provide lubricating oil for transmission mechanism.
20、汽轮机油箱为什么要装排油烟风机？
⑴油箱装设排油烟风机的作用是排除油箱中的气体和水蒸气。

这样一方面使水蒸气不在油箱中凝结；另一方面使油箱中压力不高于大气压力，使轴承回油顺利地流入油箱。

⑵反之，如果油箱密闭，那么大量气体和水蒸气积在油箱中产生正压，会影响轴承的回油，同时易使油箱油中积水。

⑶排油烟风机还有排除有害气体使油质不易劣化的作用。

Why should the oil tank of a steam turbine be equipped with a fume exhaust fan?
(1) The function of installing exhaust fan in oil tank is to remove gas and water vapor in oil tank. In this way, on the one hand, water vapor does not condensate in the tank; on the other hand, the pressure in the tank is not higher than the atmospheric pressure, so that the bearing oil returns to the tank smoothly.
(2) Conversely, if the tank is sealed, a large amount of gas and water vapor accumulate in the tank to generate positive pressure, which will affect the bearing oil return, and easily cause water accumulation in the tank oil.
(3) The exhaust fan also has the function of eliminating harmful gases to make the oil quality not easy to deteriorate.
21、油箱底部为什么要安装放水管？
汽轮机运行中，由于轴封漏汽大、水冷发电机转子进水法兰漏水过多等原因，使汽轮机油中带水。

这些带有水分的油回到油箱后，因为水的比重大，水与油分离后沉积在油箱底部。

及时排除这些水可避免已经分离出来的水再与油混合使油质劣化。

所以油箱底部都装有放水管。

Why install the drain pipe at the bottom of the tank?
In the operation of steam turbines, water is carried in the oil of steam turbines due to the large leakage of steam from shaft seals and the excessive leakage of water from the inlet flange of the rotor of water-cooled generators. These oils with water return to the tank, because of the large proportion of water, water and oil are separated and deposited at the bottom of the tank. The timely removal of these water can avoid the deterioration of oil quality by mixing separated water with oil. So the bottom of the tank is equipped with drain pipes.
22、汽轮机油油质劣化有什么危害？
汽轮机油质量的好坏与汽轮机能否正常运行关系密切。

油质变坏使润滑油的性能和油膜力发生变化，造成各润滑部分不能很好润滑，结果使轴瓦乌金熔化损坏；还会使调节系统部件被腐蚀、生锈卡涩，导致调节系统和保护装置动作失灵的严重后果。

所以必须重视对汽轮机油质量的监督。

What are the hazards of deterioration of turbine oil quality?
The quality of steam turbine oil is closely related to the normal operation of steam turbine. The deterioration of oil quality makes the performance of lubricating oil and oil film force change, resulting in the failure of lubricating parts, resulting in the melting damage of bearing bushes, corrosion and rusting of regulating system components, resulting in serious consequences of failure of regulating system and protective device. Therefore, we must pay attention to the supervision of the quality of turbine oil.
23、汽轮机调节系统的任务是什么？
汽轮机调节系统的基本任务是：在外界负荷变化时，及时地调节汽轮机的功率以满足用户用电量变化的需要，同时保证汽轮机发电机组的工作转速在正常允许范围之内。

What is the task of the steam turbine governing system?
The basic task of the steam turbine governing system is to adjust the power of the steam turbine in time to meet the needs of users when the external load changes, and to ensure that the working speed of the steam turbine generator set is within the normal allowable range.
24、调节系统一般应满足哪些要求？
调节系统应满足如下要求：
⑴当主汽门全开时，能维持空负荷运行。

⑵由满负荷突降到零负荷时，能使汽轮机转速保持在危急保安器（ETS保护）动作转速以下。

⑶当增、减负荷进，调节系统应动作平稳，无晃动现象。

⑷当危急保安器（ETS保护）动作后，应保证高、中压主汽门、调节汽门迅速关闭。

⑸调节系统速度变动率应满足要求（一般在4%～6%），迟缓率越小越好，一般应在0.5%以下。

What requirements should the regulation system generally meet?
The regulation system shall meet the following requirements:
(1) When the main valve is fully open, it can maintain no-load operation.
(2) When the full load is suddenly reduced to zero load, the speed of the steam turbine can be kept below the operating speed of the emergency safety device (ETS protection).
(3) When the load is increased or decreased, the regulating system should operate smoothly and without sloshing.
(4) When the emergency safety device (ETS protection) operates, it should ensure that the high and medium pressure main valves and regulating valves close quickly.
(5) The speed change rate of the regulation system should meet the requirements (generally 4%-6%), the smaller the delay rate, the better, generally less than 0.5%.
25、汽轮机调节系统一般由哪几个机构组成？
汽轮机的调节系统根据其动作过程，一般由转速感受机构、传动放大机构、执行机构、反馈装置等组成。

What are the general components of a steam turbine governing system?
The governing system of steam turbine is generally composed of speed sensing mechanism, transmission amplification mechanism, actuator and feedback device according to its operation process.
26、为什么调节系统要做动态、静态特性试验？
调节系统静态特性试验的目的是测定调节系统的静态特性曲线、速度变动率、迟缓率，全面了解调节系统的工作性能是否正确、可靠、灵活；分析调节系统产生缺陷的原因，以正确地消除缺陷。

调节系统动态特性试验的目的是测取甩负荷时转速飞升曲线，以便准确地评价过渡过程的品质，改善调节系统的动态调节品质。

Why do the dynamic and static characteristics tests of the regulating system need to be done?
The purpose of the static characteristic test of the regulating system is to determine the static characteristic curve, the rate of speed change and the rate of retardation of the regulating system, to fully understand whether the working performance of the regulating system is correct, reliable and flexible, and to analyze the causes of the defects of the regulating system so as to correctly eliminate the defects.
The purpose of the dynamic characteristic test of the regulation system is to measure the speed rise curve during load rejection, so as to accurately evaluate the quality of the transition process and improve the dynamic regulation quality of the regulation system.
27、汽轮机为什么必须有保护装置？
为了保证汽轮机设备的安全，防止设备损坏事故的发生，除了要求调节系统动作可靠以外，还应该具有必要的保护装置，以便汽轮机遇到调节系统失灵或其他事故时，能及时动作，迅速停机，避免造成设备损坏等事故。

Why do steam turbines have to have protective devices?
In order to ensure the safety of steam turbine equipment and prevent the occurrence of equipment damage accidents, besides requiring reliable operation of the regulating system, the necessary protective devices should also be provided so that the steam turbine can act in time when the regulating system fails or other accidents occur, stop the turbine quickly, and avoid such accidents as equipment damage.
28、自动主汽门的作用是什么？
自动主汽门的作用是在汽轮机保护装置动作后，迅速切断汽轮机的进汽并使汽轮机停止运行。

因此，它是保护装置的执行元件。

What is the function of the automatic main valve?
The function of the automatic main valve is to cut off the steam intake and stop the operation of the steam turbine quickly after the action of the protective device of the steam turbine. Therefore, it is the actuator of the protection device.
29、对自动主汽门有什么要求？
为了保证安全，要求自动主汽门动作迅速，并关闭严密，对于高压汽轮机来说，在正常进汽参数和排汽压力的情况下，自动主汽门关闭后（调节汽门全开），汽轮机转速应能够降低到1000r／min以下。

自汽轮机保护系统动作到主汽门完全关闭的时间，通常要求不大于0.5s。

What are the requirements for automatic main valve?
In order to ensure safety, the automatic main valve is required to move quickly and close tightly. For high pressure steam turbines, after the automatic main valve is closed (the regulating valve is fully opened), the speed of the steam turbine should be reduced to less than 1000r/min under normal intake parameters and exhaust pressure. The time from the operation of the steam turbine protection system to the complete closure of the main valve is usually not more than 0.5s.
30、为什么通常主汽门都是以油压开启，而以弹簧力来关闭？
这是因为在任何事故情况下，包括在油源断绝时，自动主汽门仍应能迅速关闭。

所以一般主汽门都设计成以弹簧力来关闭。

Why is the main valve usually opened by oil pressure and closed by spring force? This is because in any accident situation, including when the oil source is cut off, the automatic main valve should still be able to close quickly. So the main valve is usually designed to close by spring force.
31、汽轮机轴向位移保护装置起什么作用？
汽轮机转子与静子之间的轴向间隙很小，当转子的轴向推力过大，致使推力轴承乌金熔化时，转子将产生不允许的轴向位移，造成动静部分摩擦，导致设备严重损坏事故，因此汽轮机都装有轴向位移保护装置。

其作用是：当轴向位移达到一定数值时，发出报警信号；当轴向位移达到危险值时，保护装置动作，切断汽轮机进汽，停机。

What role does the axial displacement protection device of steam turbine play? The axial clearance between the rotor and the stator is very small. When the axial thrust of the rotor is too large, the thrust bearing melts, the rotor will produce an impermissible axial displacement, which will cause friction between the static and dynamic parts, resulting in serious damage to the equipment. Therefore, the turbine is equipped with an axial displacement protection device. Its function is to send an alarm signal when the axial displacement reaches a certain value; when the axial displacement reaches a dangerous value, the protective device acts to cut off the steam intake and stop the turbine.
32、低油压保护装置一般具有以下作用：
⑴润滑油压低于正常要求数值时，首先发出信号，提醒运行人员注意并及时采取措施。

⑵油压继续下降到某数值时，自动投入备用油泵（备用交流润滑油泵和直流油泵），以提高油压。

⑶备用油泵投入后，仍继续跌到某一数值应掉闸停机。

Low oil pressure protection devices generally have the following functions:
(1) When the lubricating oil pressure is lower than the normal value, the signal should be sent first to remind operators to pay attention to and take timely measures.
(2) When the oil pressure continues to drop to a certain value, the standby oil pump (alternating current lubricating oil pump and direct current oil pump) is
automatically put into operation to improve the oil pressure.
(3) After the standby oil pump is put into operation, it still falls to a certain value and should be shut down.
33、低真空保护装置的作用是什么？
汽轮机运行中真空降低，不仅会影响汽轮机的出力和降低热经济性，而且真空降低过多还会因排汽温度过高和轴向推力增加影响汽轮机安全。

因此大功率的汽轮机均装有低真空保护装置。

当真空降低到一定数值时，发出报警信号，真空降至规定的极限时，能自动停机。

以保护汽轮机免受损坏。

What is the function of low vacuum protection device?
The reduction of vacuum in the operation of steam turbine will not only affect the output of steam turbine and reduce the thermal economy, but also affect the safety of steam turbine because of the high exhaust temperature and the increase of axial thrust. Therefore, high-power steam turbines are equipped with low vacuum protection devices.
When the vacuum is reduced to a certain value, an alarm signal is sent, and when the vacuum is reduced to the prescribed limit, the machine can stop automatically. To protect the steam turbine from damage.
34、凝汽设备的作用是什么？
凝汽设备的作用是：
⑴凝汽器用来冷却汽轮机排汽，使之凝结为水，再由凝结水泵送到除氧器，经给水泵送到锅炉。

凝结水在发电厂是非常珍贵的，尤其对高温、高压设备。

因此在汽轮机运行中，监视和保证凝结水是非常重要的。

⑵在汽轮机排汽口造成高度真空，使蒸汽中所含的热量尽可能被用来发电，因此，凝汽器工作的好坏，对发电厂经济性影响极大。

⑶在正常运行中凝汽器有除气作用，能除去凝结水中的含氧，从而提高给水质量防止设备腐蚀。

What is the function of condensing equipment?
The functions of condensing equipment are:
(1) Condenser is used to cool the exhaust steam of steam turbine, condensate it into water, then send it to deaerator by condensate pump and to boiler by feed water pump. Condensate water is very precious in power plants, especially for high temperature and high pressure equipment. Therefore, it is very important to monitor and ensure condensate water in the operation of steam turbine.
(2) High vacuum is created in the exhaust nozzle of the steam turbine, so that the heat contained in the steam can be used to generate electricity as far as possible. Therefore, the quality of condenser operation has a great impact on the economy of the power plant.
(3)In normal operation, condenser has degassing effect, which can remove oxygen in condensate water, thus improving the quality of feed water and preventing equipment from corrosion.
35、什么是凝汽器的极限真空？
凝汽设备在运行中应该从各方面采取措施以获得良好真空。

但真空的提高也不是越高越好，而有一个极限。

这个真空的极限由汽轮机最后一级叶片出口截面的膨胀极限所决定。

当通过最后一级叶片的蒸汽已达到膨胀极限时，如果继续提高真空，不可能得到经济上的效益，反
而会降低经济效益。

简单地说，当蒸汽在末级叶片中的膨胀达到极限时，所对应的真空称为极限真空，也有的称之为临界真空。

What is the limit vacuum of condenser?
Measures should be taken to obtain good vacuum in operation of condensing equipment. But the higher the vacuum is, the better. There is a limit. This vacuum limit is determined by the expansion limit of the exit section of the last stage blade of a steam turbine. When the vapor passing through the last stage blade reaches the expansion limit, if the vacuum is continuously raised, the economic benefit can not be obtained, but the economic benefit will be reduced.
Simply put, when the expansion of steam in the last stage blade reaches the limit, the corresponding vacuum is called the limit vacuum, or the critical vacuum. 36、什么是凝汽器的最有利真空？
对于结构已确定的凝汽器，在极限真空内，当蒸汽参数和流量不变时，提高真空使蒸汽在汽轮机中的可用焓降增大，就会相应增加发电机的输出功率。

但是在提高真空的同时，需要向凝汽器多供冷却水，从而增加循环水泵的耗功。

由于凝汽器真空提高，使汽轮机功率增加与循环水泵多耗功率的差数为最大时的真空值称为凝汽器的最有利真空（即最经济真空）。

影响凝汽器最有利真空的主要因素是：进入凝汽器的蒸汽流量、汽轮机排汽压力、冷却水的进口温度、循环水量（或是循环水泵的运行台数）、汽轮机的出力变化及循环水泵的耗电量变化等。

实际运行中则是根据凝汽量及冷却水进口温度来选用最有利真空下的冷却水量，也即是合理调度使用循环水泵的容量和台数。

What is the most favorable vacuum for condensers?
For the condenser whose structure has been determined, in the limit vacuum, when the steam parameters and flow rate remain unchanged, increasing the vacuum will increase the available enthalpy drop of steam in the steam turbine, and the output power of the generator will be increased accordingly. However, while increasing the vacuum, more cooling water is needed to the condenser to increase the power consumption of the circulating water pump. The vacuum value of the condenser when the difference between the power increase of the steam turbine and the power consumption of the circulating pump is maximum is called the most favorable vacuum of the condenser (i.e. the most economical vacuum).
The main factors affecting the condensator's most favorable vacuum are: the steam flow into the condenser, the exhaust pressure of the steam turbine, the inlet temperature of the cooling water, the amount of circulating water (or the number of circulating pumps), the output of the steam turbine and the power consumption of the circulating pump. In actual operation, the most favorable cooling water quantity under vacuum is selected according to the condensation amount and the inlet temperature of cooling water, that is, the capacity and number of circulating water pumps are reasonably dispatched and used.
37、凝汽器为什么要有热井？
热井的作用是集聚凝结水，有利于凝结水泵的正常运行。

热井贮存一定数量的水，保证甩负荷时不使凝结水泵马上断水。

热井的容积一般要求相当于满负荷时约0.5～10min内所聚集的凝结水流量。

Why do condensers have hot wells?
The function of hot well is to collect condensate water, which is beneficial to。