热能专业英语Ch 03 教案

1、Chapter 3 Steam turbineWords and ExpressionsAccess 通道，入口Coverband 围带Admiralty brass 海军铜Crane 起重机，吊车Aluminium brass 铝黄铜Critical speed 临界转速Annex 附属建筑物，附录Cylinder 圆筒，汽缸Aspect ratio 相对高度Debris 矸石， 有机残留物Assembly组件，装配Deflector 导向器，致偏板Attachment 附件 连接设备Detail 零件，零件图Backpressure背压Diaphragm 隔板Balance piston

2、平衡活塞Diode 二极管Bearing box 轴承箱Dismantling 拆除Bellows 膜盒，波纹筒Double-shell casing 双层缸Blade 叶片，刀片Drum type rotor 鼓形转子Blower送风机、吹灰器Ductility 黏性， 延展性Bolting螺栓连接Dynamic balance 动平衡Boundary layer 边界层Elastic arch banding 弹性拱形围带Brittle fracture 脆性断裂Excitation 励磁，扰动Built-up blade 组合式叶片Fabrication 装配Built-up rotor

3、 套装转子Fastening 连系， 紧固Carrier ring 持环Fatigue cracking 疲劳断裂Case壳，罩Finger-shaped pinned fixing 叉形叶根Casing 套管，外壳，箱Fitting 装配Cast 铸造Fixed blade 固定叶片， 导向叶片Cast-in blade 铸造叶片Flange 法兰Chimney 烟囱Flange warming steam 法兰加热蒸汽Chord弦，翼长Flexible coupling 挠性联轴器Computer-aided design 计算机辅助设计Flexible rotor 挠性转子Converg

4、ent-divergent type nozzle 缩放式喷嘴Flue gas 烟气cooling tower 冷却塔Forging 锻件Coupling 连接，联轴器Fracture 裂面，裂纹，断裂Full admission 全周进汽Out-of-balance weight 不平衡重量Gland housing 轴封腔室Overlap 重叠，Head 汽包封头Partial admission部分进汽Heat transmission 传热Pedestals 支架，轴架Impeller 叶轮，推进器Penetrations 穿透，渗透Impulse 冲击，冲动Penultimate s

5、tage次末级Impulse turbine 冲动式汽轮机Pitch 节距Incidence angle 入射角Purge 清洗Inlet belt 入口区域Rating额定功率，额定值Inner casing内缸Reaction 反作用Integral rotor 整锻转子Reaction machine 反动式汽轮机Inter-shell 缸间Resonance 共振Jig夹具，模具，钻具Rigid coupling刚性联轴器Key 键Rigid rotor刚性转子Lacing wire 拉金rim边缘Large turbine-generator unit 大型汽轮发电机组Rivet 铆

6、钉，铆接Liquid-ring type air pump 水环式真空泵Robust 坚固的Mach number 马赫数Root根部Makeup 补给，补充Rotor转子Monobloc rotor 整锻转子Rupture 断裂Monolithic 单一的、整体的、整铸的s.w.g.钢丝线规Moving blade 动叶片，Semi-flexible coupling 半挠性联轴器Nest一套，塔齿轮Shoulder 肩Nozzle 喷嘴Shrink fit 冷缩配合Nozzle box 喷嘴室Shrink-on disc rotor 套装转子Nozzle governing 喷嘴调节Shr

7、ounding包箍Numerically-controlled machine 数控机床Skirt 环、套筒Offset 补偿、抵消Sleeve 套筒On-site 现场Slot槽Operational speed 运行速度Solid coupling刚性联轴器Outer casing外缸Stage 级Static balance 静平衡AbbreviationsSteam bending stress 蒸汽弯曲应力FATT脆性转变温度Straight or curved fir-tree root 枞树形叶根NDT 无损检测Stress concentration 应力集中O.D.外径Stu

8、b shaft 短轴CFD计算流体力学Tenon 凸榫BFP锅炉给水泵Throttle governing 节流调节BFPT 锅炉给水泵汽轮机Tip seal 叶顶密封LP 低压缸Toughness 韧度HP 高压缸Turbine汽轮机IP 中压缸Twisted moving blade扭叶片CW循环水Two-shift operation 两班制运行AGR改进气冷反应堆Velocity-compounded stage 复速级FWT 给水温度Velocity triangle速度三角形FRF 抗燃油Ventilation 通风GSC轴封蒸汽冷却器Wake 尾流，尾迹NPSH静压头Welded

9、 disc rotor 焊接转子PWR压水堆Wheel 齿轮SV 主气阀TTD端差3.1 IntroductionSteam turbine is one of the most important power generating turbo-machines. It is the principal prime mover in the field of electric power generation. The role of the steam turbine as one of the components in the steam power plant is briefly d

10、iscussed in this chapter.3.1 引言蒸汽轮机是最重要的涡轮发动机之一，是发电领域的主要原动机。本文简单讨论了作为蒸汽轮机发电厂部件之一的蒸汽轮机的作用。For a simple steam turbine plant, the first component is the steam boiler which raises steam at the required pressure and temperature for the turbine. The boiler receives feed water at an elevated temperature th

11、rough various regenerative and heat recuperating apparatuses. In a majority of power plants steam is superheated; in large plants it is reheated once or twice after expanding through some stages.对于一个简单的蒸汽轮机发电厂，第一个部件就是把蒸汽提高到汽轮机所需压力和温度的蒸汽锅炉。蒸汽锅炉接受经过不同回热和热回收装置提高了温度的给水。在大多数电厂中，采用了过热蒸汽；大型电厂中，蒸汽在汽轮机的一些级中膨

12、胀后，要经过一次或两次再热。Superheated steam enters the steam turbine through the governor value. The steam turbine is invariably a multistage machine having one or more cylinders depending on the plant size.过热蒸汽经过调节阀进入蒸汽轮机。蒸汽轮机总是多级汽轮机，根据汽轮机容量的大小采用一个或多个缸。The steam after expanding through the turbine condenses in

13、 the condenser at a low pressure i.e. 0.5071.014 psi(0.00350.007MPa). The condensate along with the bled steam is pumped to the boiler.在汽轮机中膨胀后的蒸汽在凝汽器中以低压凝结（0.0035 到 0.007 MPa）。凝结水以及抽汽用泵打入锅炉。3.1.1 Types of steam turbinesVarious types of steam turbines can be classified in the following manner.On the

14、 basis of flow directionl Axiall Radial3.1.1 蒸汽轮机的类型蒸汽轮机可用以下方式分为许多类型。根据流向 轴向 径向On the basis of expansion processl Impulsel Reactionl Combined impulse and reaction根据膨胀过程 冲动式 反动式 冲动反动混合式On the basis of number of stagesl Single stagel Multi-stage根据级的个数 单级 多级On the basis of steam entry configurationl Fu

15、ll admissionl Partial admission根据汽轮机入口结构 全周进汽 部分进汽On the basis of number of flowsl Single flowl Double flowl Tandem or cross compounded根据汽流个数 单流 双流 单轴或双轴教材48页On the basis of rational speedl N=3000rpm, f=50Hzl N=3600rpm, f=60Hzl N=1500rpml Geared units根据转速 N=3000rpm, f=50Hz N=3600rpm, f=60Hz N=1500rp

16、m 变速机组On the basis of applicationsl Electric power generationl Industriall Marine根据应用 发电 工厂用 船用On the basis of steam conditions.l Low pressure turbines, using steam at pressures of 17.3928.98 psi(0.120.2MPa)l Medium pressure turbines, using steam at pressures up to 28.98 psi(0.2MPa)l High pressure t

17、urbines, utilizing steam at pressures of 28.982434.32 psi (0.216.8MPa) and higher and temperature of 995 F (535) and higher.l Turbines of supercritical pressures, using steam at pressures of 3216.78 psi (22.2MPa) and above.根据蒸汽参数 低压汽轮机，采用压力为0.12 到 0.2 MPa的蒸汽; 中压汽轮机，蒸汽压力达到0.2 MPa； 高压汽轮机，采用压力为0.2到16.8

18、 MPa或更高压力，温度为535或更高温度的蒸汽； 超临界压力汽轮机，采用蒸汽压力为22.2 MPa或大于此压力。3.1.2 Impulse machines3.1.2 冲动式汽轮机Machines in which there is no change of static or pressure head of the fluid in the rotor are known as impulse machine. 冲动式汽轮机是指在转子中没有流体静压头改变的汽轮机。The rotor blades only cause energy transfer without any energy

19、transformation.转子叶片仅仅引起能量的传递而没有任何能量的转变。 The energy transformation from pressure or static head to kinetic energy or vice versa takes place only in fixed blades. 由压能转变为动能或动能转变为压能的能量转换仅仅发生在静叶片中。For example, the transfer of kinetic energy of a high velocity fluid to the impulse action of the fluid on t

20、he rotor. 在冲动式汽轮机中，高速流体的动能传递到转子上仅仅由于作用在转子上的流体冲动力。Fig.3-1 shows a typical impulse-type stage velocity diagram. The relative velocity of the steam leaving the moving blades (w2) is less than the relative velocity of the steam entering the moving blades (w1). 图3-1给出了典型的冲动级速度三角形图。动叶出口蒸汽的相对速度(W2)小于动叶入口的相

21、对速度(W1)。This shows that conversion of kinetic energy to mechanical energy takes place in the moving blades. 这表示了在动叶中发生了动能向机械功的转化。Since the rotor blade passages in an impulse turbine do not cause any acceleration of the fluid, the chances of its separation due to boundary layer growth on the blade su

22、rfaces are greater. 由于在冲动式汽轮机中转子叶片通道不会引起流体的任何加速，在叶片表面由于附面层的增加引起流体分离的机率要大一些。On account of this, the rotor blade passages of the impulse machine suffer greater losses giving lower stage efficiencies. 由此，冲动式汽轮机中转子叶片通道的损失较大，导致了较低的级效率。uC1w1w2C2uuC1w1w2C2u图.3-1 冲动级速度三角形图 图.3-2 反动级速度三角形图U=动叶轮周速度, m/s c1 =动

23、叶入口蒸汽的绝对速度, m/sC2 =动叶出口蒸汽绝对速度, m/s w1 =动叶入口蒸汽的相对速度, m/sw2 =动叶出口蒸汽相对速度, m/s3.1.3 Reaction machinesThe degree of reaction of a turbo-machine stage is defined as the ratio of the static or pressure head change occurring in the rotor to the total change across the stage.教材49页3.1.3 反动式汽轮机涡轮机械级的反动度定义为转子中发

24、生的压头改变与整级的全部压头改变之比。Turbo-machines or their stages in which changes in static or pressure head occur both in the rotor and stator blade passages are known as reaction machines or stages. 在转子叶片通道和静子叶片通道都有压头改变的涡轮机或级称作为反动式涡轮机或反动级。 Here the energy transformation occurs both in fixed as well as moving bla

25、des. 其中，在静叶和动叶中都有能量的转换。 The rotor experiences both energy transfer and transformation. Therefore reaction turbines are expected to be more efficient on account of the continuously accelerating flow and lower losses.转子上既有能量传递又有能量转变。因此在反动式汽轮机中，由于流体的连续加速及较低的损失，它的效率应当高一些。 50% or half degree reaction mac

26、hine has some special characteristics. Axial flow turbines and compressors with 50% reaction have symmetrical blades in their rotors and stators. It may be noted that velocity triangles at the entry and exit of a 50% stage are also symmetrical. Fig.3-2 shows a typical reaction-type stage velocity di

27、agram. The relative velocity of the steam leaving the moving blades (w2) is greater than the relative velocity of the steam entering the moving blades (w1). This is because of the increase in velocity through the moving blades due to the heat drop there.反动度为50%或一半的涡轮机有一些特殊的特点。反动度为50%的轴流式涡轮机和压缩机转子和静子

28、上的叶片对称。对于反动度为50%的级，可看出它的出口和入口速度三角形也是对称的。图3-2给出了典型的反动级的速度三角形。动叶出口的蒸汽相对速度(W2)大于动叶入口的蒸汽相对速度(W1)：这是由于动叶的焓降导致通过动叶的速度增加。3.1.4 Multi-stage machinesIt will be seen later for a given rotor speed only a limited changes in the energy level of the fluid can occur in a turbo-machine stage. This holds equally for

29、 turbines, compressors, pumps and blowers. Therefore in applications where a large change in the energy level is required, more than one stage is employed.3.1.4 多级汽轮机后面可以看到，当转速给定时，在涡轮机械的一级中，流体能量水平的改变是有限的。这对于涡轮机、压缩机、泵和吹灰器是一样的。因此，在能量水平改变很大的应用中，采用了多级。Multi-stage machines may employ only impulse or reac

30、tion stages or a combination of these. Impulse machines may utilize a large pressure drop in a number of pressure stages or a high kinetic energy in a number of velocity stages; a combination of pressure and velocity stages in impulse machines is also employed. In certain compressor applications it

31、is profitable to use axial and radial stages in the same machine. Different stages may be mounted on one or more shafts.在多级汽轮机中，可仅采用冲动级或采用反动级或冲动级和反动级的组合。冲动式汽轮机可采用许多压力级承担大的压降或许多速度级承担高的动能。还可同时采用速度级和压力级。在一定的压缩机中，同一个机械上采用了轴向流动的级和静向流动的级是有意义的。不同的级可安装在一个或多个轴上。In large steam turbines the difference of steam

32、 pressure between the boiler and the condenser is very large. If this was to be utilized in a single stage, a rotor of an impracticably large diameter at a very high speed would have to be used. This would create, besides manufacturing difficulties, serious strength and bearing problems.在大型汽轮机中，锅炉出口

33、和凝汽器入口的蒸汽压差非常大。如果汽轮机中只有一个级，那么就需要采用一个高转速的直径很大的转子，这不仅会使制造困难，而且会引起严重的强度和支承问题。Generally a multi-stage steam turbine consists of the following essential parts:(1) A casing usually divided at the horizontal centerline, with the halves bolted together for ease of assembly and disassembly, and containing th

34、e stationary blade system.(2) A rotor with the moving blades on wheels, and with bearing journals on the rotor.(3) A bearing box in the casing, supporting the shaft.教材50页一般说来，一个多级蒸汽轮机基本由下面几部分组成：（1） 汽缸，为了便于装配和拆卸，通常汽缸在水平中分面分开为两半，这两半由螺栓连接，用于支承静止叶片系统。（2） 转子，转子上有动叶片安装在叶轮上，以及还有叶轮。（3） 轴承箱 置于汽缸中，用于支承轴(4) A

35、governor and valve system for regulating the speed and power of the turbine by controlling the steam flow, and an oil system for lubrication of the bearings and a set of safety devices.(5) A coupling of some sort to connect with the driven machine.(6) Pipe connection to a supply of steam at the inle

36、t, and to an exhaust system at the outlet of the casing.（4） 调节系统 依靠控制蒸汽流量，调节汽轮机转速和出力，还有用于轴承润滑的油系统和一组安全装置（5） 联轴器 用于转子的连接，并与发电机相连；（6） 管道 与汽缸入口蒸汽供给管道、汽缸出口排汽系统相连。3.2 Casing constructionA turbine cylinder is essentially a pressure vessel with its weight supported at each end on the horizontal centerline.

37、 It is designed to withstand hoop stresses in the transverse plane, and to be very stiff in the longitudinal; direction in order to maintain accurate clearances between the stationary and rotating parts of the turbine.3.2 汽缸结构汽轮机汽缸实质上是一个压力容器，在水平中心线的两端支撑它的重量。设计中要求在汽缸的横断面上，能承担管道的应力，而且沿汽缸的长度方向，要有一定的刚性从

38、而维持汽轮机动静部分准确的间隙。The design is complicated by the need for internal access, all casings being split along their horizontal centerline, allowing the rotor to be inserted as a complete assembly. Substantial flanges and bolting are required to withstand the pressure forces at he horizontal joints. The r

39、elatively massive flanges respond more slowly to temperature changes than the rest of the casing, resulting in different rates of expansion and setting-up of temperature stress and distortion, although these are minimized by the application of flange warming steam. Further stress complexities are se

40、t up by the gland housing and steam entry and exit passages.汽缸由于内部通道的需要使得其设计复杂。所有的汽缸都从水平中分面分开，从而使转子能放入汽缸内和汽缸装配为一个整体。在汽缸的水平结合面上，设置了巨大的法兰和螺栓用以承担压力。相比汽缸的其余部分，相对厚重的法兰对温度变化的反应较慢，导致了不同的膨胀率，产生了温度应力和变形，尽管这些在汽轮机中已采用了法兰加热蒸汽使其减至最低程度。轴封汽室和蒸汽出入通道使得应力进一步复杂。HP and IP casings are of cast construction and are circul

41、ar in cross-section to minimize non-membrane stresses. Flanges, bolting, steam penetrations and other features are as far as possible symmetrically arranged to reduce thermal asymmetry and hence distortion. LP casings may be fabricated or a combination of castings and fabrications.高压和中压汽缸都是铸造结构，并且在横

42、截面上采用圆形结构从而使得应力达到最小。法兰、螺栓、蒸汽出入通道和其他特征尽可能布置成对称结构，从而减少热不对称和由此引起的变形。低压汽缸可以采用装配结构或装配与铸造组合的结构。图3-3高压缸轴向剖面图As with all pressure vessels, the integrity of the design is checked after manufacture with a hydraulic pressure test, to 150% of the highest working pressure.和所有的压力容器一样，汽缸在制造完后要进行液压试验检查设计的完善性，液压试验要进

43、行最高工作压力150%的压力试验。3.2.1 High pressure casingsMost modern turbines, with steam pressure over 1449psi (10MPa) and ratings greater than 100MW, have HP casings of double-shell design (Fig.3-3). This has been adopted because of the difficulty of designing a single casing to withstand the thermal and press

44、ure stresses and yet be capable of flexible operation. With a double-shell casing, the space between the shells is filled with steam at exhaust conditions, allowing each casing to be designed for smaller temperature and pressure differentials. A baffle is formed between the two casings near the exha

45、ust end as part of the inner-casing casting. The baffle extends almost to the outer casing but does not seal against it. The turbulent exhaust steam is directed by the baffle to the exhaust connections and prevented from cooling the inner casing; this reduces the temperature differentials and hence

46、stress on the inlet end of the inner casing. Steam leaking through the gland between the inner casing and the rotor at the inlet end is 教材51页piped away to the exhaust connections, so the space between the casings contains steam at exhaust conditions with a gentle flow being maintained by leakage thr

47、ough the outer casing gland.3.2.1高压汽缸 许多现代汽轮机，蒸汽压力超过10MPa并且功率大于100 MW，采用了双层缸结构的高压汽缸。这是因为高压缸既要承担热和压应力，而又能灵活运行，这时设计单层缸结构是困难的。对于双层缸结构，缸间充满了处于排汽参数的蒸汽，从而使得每层缸都能设计成承担小温差和小压差的结构。在双层缸间靠近排汽端设置了挡板，这个挡板是内缸铸件的一部分。挡板向外延伸几乎达到外缸，但没有与外缸封住。高压缸的紊流排汽在挡板的作用下排入排汽管道，避免冷却内缸；这减小了内缸进汽端的温差及由此引起的应力。从高压缸进汽端内缸和转子间轴封泄漏的蒸汽用管子排向高压

48、缸排汽处，从而使得双层缸间充满了处于排汽状态的蒸汽，并且通过外缸轴封泄漏在双层缸间维持小流量的蒸汽流动。The smaller pressure differential permits a thinner shell, which combined with the larger surface area of a double casing, allows quicker warming of the turbine on start-up. Thinner shells are also easier to cast and are likely to have fewer defect

49、s.较小的压差可以采用较薄的汽缸，这一点以及双层缸结构的较大的表面积，使得汽轮机在启动时能较快的暖机。另外薄汽缸还易于铸造，并且可能有较少的缺陷。On some machines, reversed flow blading has been adopted, where the steam is diverted back between the casings part way through its expansion, continuing through the final stages in the opposite direction. This arrangement give

50、s a higher inter-shell pressure and temperature, reducing the stress on the hot inner shell at the expense of the outer shell. It also permits simple bled-steam tapping at the inner-shell conditions and reduces the net thrust on the HP rotor.在一些汽轮机中，采用了反向流叶片，其中蒸汽在其膨胀过程中的某处，从缸间返回以相反的方向继续流过最后的级。这种布置导致

51、了较高的缸间压力和温度，在外缸应力增加的代价下减少了热内缸的应力。另外这种结构还使得以缸间参数抽汽的抽汽口结构简单，并且减少了高压转子的净推力。Triple casing have been used on some modern turbines to further reduce the stress on 教材52页the hot inner casing, and hence reduce thermal distortion. The inner casing is enclosed in a barrel-like sleeve which has no horizontal jo

52、int. The inner casing is only lightly stressed and can be relatively thin with light flanges, whilst the barrel casing which encloses it is more highly stressed. The barrel casing, however, having no flanges and being of uniform thickness can easily be designed to accommodate the stress whilst also

53、remaining relatively thin.在一些现代汽轮机中，为了进一步减少热内缸的应力以及热变形，采用了三层缸结构，内缸置于一个没有水平结合面的筒状套筒中，（这种）内缸应力小，可以做得相对薄，这样法兰也不厚，而包着它的筒状汽缸应力相对高。然而，由于筒状汽缸没有法兰，厚度均匀，因此即使相对薄，仍可承担（一定的）应力。One disadvantage of this form of triple casing is the difficulty in assembling and dismantling the HP cylinder. On assembly, the rotor h

54、as to be fitted into the inner and outer lower half, the inner casing bolted up, and then the rotor and inner casing lifted and mounted in a back jig to allow the barrel to be threaded over them. The assembly can then be lowered back into the bottom half of the outer casing, and the top-half outer c

55、asing added.三层缸的这种形式，其中一个缺点是在装配和拆卸高压汽缸时麻烦。在装配中，需要把转子装入内、外下缸中，之后把内上缸装配好，然后把转子和内缸一块吊起，置于一个特殊的夹具上，使得筒状汽缸穿过。套好后，放下置于外缸的下半部分上，最后把上半外缸扣上即可。The steam inlet pipes pass through the outer casing and deliver the steam into the inlet belt of the inner casing. The inlet belt is formed by an extension to the main

56、 casing which ensures that the inlet steam cannot come directly into contact with the rotor but must first pass out through the nozzles and the first row of moving blades.蒸汽进汽管道通过外缸，将蒸汽送入到内缸的进汽部分。进汽部分由内缸的一部分形成，这样确保入口蒸汽不直接与转子接触，而是必须首先流过喷嘴和第一列动叶栅。 With steam temperature at inlet in excess of 1000.4 F(

57、538), separate nozzle boxes of heat-resistant steel are sometimes used to protect the casing from the full temperature. These take the place of the inlet belt, delivering steam from the inlet penetrations to the first stage nozzles.当主蒸汽温度超过538时，有时会采用由耐热合金钢制造的单独喷嘴室结构，这样可以避免汽缸与最高温度的蒸汽接触。这种单独喷嘴室结构取代了进汽部分，把蒸汽从入口管道送入第一级喷嘴。Some overseas units have nozzle governing instead of the throttle governing. With nozzle governing