热能与动力工程，专业英语期末考题

选择题：

1. If the system does not exchange energy with surroundings, it is an _________

A open system B closed system C isolated system D ontrol volume

2. If the temperature of the liguid is lower than the saturation emperature for the existing

pressure,it is called a_________liquid.

A superheated B subcooled C saturation D dry saturated

3. If the efficiency of a real engine is significantly_______ the efficiency of a Carnot

engine between the same limits, thenadditional improvements may be possible. A lower than B more than C equal to D greater than

4. The velocity bector of a flow is expressed as V =ax2i+byztj, such a flow is a ____

dimensional flow.

A one B two C three D four

5. the critical Reynolds number of a rough-walled pipe is about_______. A 3x106 B 3x105 C 2000 D 1500

6. If _______，the density variations influence the flow and compressibility effects shuld

be accounted for;such flows are compressinle flows. A M>0.3 B M<0.3 C M>0.2 D M>0.1

7. Any _______effects that may exist are confined to a thin layer,called a boundary

layer,that is attached to the boundary ,the velocity in a boundary laryer is always zero at a fixed wall.

A shear B gravitational C inertial D viscous

8. The ratio of the heat transfer surface area of a heat exchanger to its volume is called

the area densityβ.A heat exchanger with_______is classifiedas being compact.

A β<700m2/m3 Bβ>700m2/m3 Cβ>500m2/m3 Dβ>1000m2/m3

9. The type of heat exchanger that involves the alternate passage of the hot and clod

fluid streams through the same flow area is the _______heat exchanger.

A regenerative B compact Cplate and frame Dshell-and -tube

10. Not all the radiation leaving one surface will reach the other surface since

electromagnetic radiation travels in straight lines and some will be lost to the surroundings,we introduce _______in net radiant exchange.

A reflectivity B emissivity C view factor D transmissivity 11. _______use heat to conver water into steam for a variety of applications. A Turbines B Boilers C Generators D Condensers

12. The modern 660MW coal-fired boilers has some _______tons of pressure parts.

A 600 B 2000 C 6000 D 20000

13. ______is burned in coal boilers to ignite the coal burners,to warm up the boiler and

raise pressure before coal is adimitted. A Coal B Gas C Water D Oil

14. The radiant superheater outlet temperature ______with an increasing boiler out-put.

A declines B increases C remains unchanged D decreases.

15. The economizer is a ______heat exchanger for recovering enery from the flue

gas.

A parallelflow B upstream C downstream D counterflow.

16. The ______utilises the heat in the boiler flue gases to heat the combustion air and

provide hot air for drying coal.

A economizer B air heater C reheater D air preheater.

17. There are no boiler tubes in the ______furnace of CFB because the rapidly moving

solids cause excessive erosion.

A topping B lower C upper D middle

18. The job of the pulverizers is to ______the feed coal down to a suitable size.

A grind B heat C crush D warm

19. The ball-and tube mill is a ______cylinder,partly filled with small diameter balls .

A declining B vertical C screwy D horizontal

20. The Universal Pressure boiler is designed to maintain a ______flow inside the

furance circuits to prevent furace tube overheating during all operating conditions A maximal B minimum C middley D generic

21. The steam after expending through the ______condenses in the condenser at a low

press.

A turbine B heater C boiler D HP cylinder

22. Machines in which there is no change of static or pressure head of the fluid in the

rotor are known as ______machine.

A reaction B impulse C combined impulse and reaction D multi-stage 23. The ______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. A degree of reaction B pressure C efficiency D enthalpy

24. For a turbine cylinder, substantial flanges and _____are required to withstand the

pressure forces at the horizontal joints.

A coupling B pipe C bolting D flange warming syetem

25. With _____governing, the inlet belt is divided into sections each controlled by a sper

–ate valve opening in sequence,resulting in a more complicated casting. A throttle B nozzle C slide pressure D constant pressure

26. _____rotors required very careful attention to shrink fit and location geometries to

avoid problems in running and with fatigue cracking. A integral B Monobloc C built-up D drum

27. _____construction has the advantage of smaller forging components at the expense

of high integrity welding.

A integral B shrink-on disc C sub-critical D Welded

28. _____means that the weight is evenly disposed around the axis of the

shaft. . A Static balance B Dynamic balance C balance D Unbalance

29. If critical speed is below running speed,the shaft is regarded as _____

A rigid B flexible C semi-flexible D super-critical

30 As a_____stage uses approximately the same heat drop as four impulse stage, it is used

to provide a shorter and cheaper turbine ,although with some sacrifice in efficiency. A impulse B reaction Cvelocity-compounded D single

单词及词组

aiabatic

baffle blade boiler

boundary layer Carnot cycle composition compressibility condensation conduction convenction diffusion

dry saturated vapor emissivity equilibrium friction loss

internal combustion engine isentropic isobaric

isolated system isometric isothermal laminar manuscript moisture molecule pathline pump quality radiation

Rankine cycle Reversible Saturation steady streamline

subcooled liquid superheated vapor surrounding turbulent ultrasonic vacuum viscous

Anchor Atomized Blast 鼓风

支座，固定 雾化 Blowdown 排污 Axis 轴

Circulating fluidized bed CFB循环流化床锅炉 Compressor 压缩机、压气机 Coordinated 坐标，定位 Counterflow 逆流（换热器） Creep strength 蠕变强度 Critical pressure 临界压力 Deterioration 恶化 Distortion 变形 Distillate 馏出物 Drainage 疏水 Drum 汽包

Economizer 省煤器

Erosive 侵蚀的，腐蚀的 Embrittlement 脆性，脆化 Evaluate 评估，评价 Ferrite 铁素体 Furnace 炉膛

Generator 发电机 Govern 控制、调节

Hydraulic 水力的，液压的 Ignite 点火 Inert 惰性 Ingredients 成分 Inorganic 无机的 Limestone 石灰石

Margin 裕量，安全系数 Mill 磨煤机

Organisms 有机体

Heterogeneous 不均匀的 Hydraulic 水力的，液压的

Ignite 点火 Plasma spray coating 等离子喷涂 Impurity 杂质

Prefabricated 预制的 Inert 惰性

Inferior 低级的，劣质的 Ingredients 成分

Premium fuel 优质燃料 Oxidation 氧化 Polymer 聚合物 Porosity多空的 Radius 半径，范围

Retract缩回

Resonant 共振

Reynolds number 雷诺数 Rare earth element 稀土元素 Regulate 控制，调节 Rigid 刚性的，紧密地 Rollers 辊子

Regenerator 回热器，蓄热器 Sootblower 吹灰器 Saturated 饱和的

Stress corrosion 应力腐蚀 Superheater 过热器

Temperature-entropy 温熵图 Tenacious 黏的

Thermodynamics 热力学 Turbine 汽轮机 Viscosity 黏度 Velocity 速度 Wear磨损 Welded 焊接 Access Assembly Back press Balance piston Bearing box Blower

Boundary layer Brittle fracture Carrier ring Casing Cast Chord

Convergent-divergent type nozzle Coupling Coverband Crane

Double-shell casing Ductility

Dynamic balance Fabrication

Fatigue cracking Fixed blade Flexible rotor Forging

Fracture

Full admission Head Impulse

Impulse turbine Inner casing Key

Lacing wire Mach number Makeup

Monobloc rotor Moving blade Nozzle box

Nozzle governing Offset

Penetrations

Penultimate stage Reaction machine Resonance Rigid rotor Rivet Robust Rupture

Static balance Throttle governing Toughness Wake Wheel Twisted 三.翻译

Thermodynamics is a science in which the storage,transfer of energy are studied.Energy is stored as internal energy,kinetic energy,potential energy and chemical energy; it is transformed from one of these forms to another;and it is transferred across a boundary as either heat or work.

If a substance exists as vapor at the temperature,it is called saturated vapor.when the vapor is at a temperature greater than the saturation temperature,it is said to exist as superheated vapor.The pressure and temperature of superheated vapor are independent properties,since the temperature may increase while the pressure remainea constant.

The first law of thermodynamics is commonly called the law of conservation of energy.In elementary physics course ,the study of conservation of energy emphasizes changes in kinetic and potentical energy and their relationship to work.A more general form of conservation of energy includes the effects of heat transfer and internal energy changes.Other forms of energy could also be included,such as electrostatic, magnetic,strain,and surface energy.

Steam discharged from the turbine is directed into a condenser for two reasons.The condenser is operated at a high vacuum in order to create a low turbine exhaust pressure,ranging

down to 12mercury,abs.Turbines are ordinarily equipped with surface condensers that are indirect or nonmixing –type heat exchangers.In the abence of mixing,the second function of the condenser can be realized,that is ,the reture of the condenate to the boiler.beacause of the high steam flow,the condensate must be conserved,otherwise the operation of a large power boiler would be impracticable.

A fluid flow may be broadly classified as either a viscous flow or an inviscid flow.An inviscid flow is one in which viscous effects of viscosity are important and cannot be ignored.

To model an inviscid flow analytically,we can simply let the viscosity be zero;this will obviously make all viscous effects zero. It is more difficult to create an inviscid floe experimentally ,because all fluids of interest have viscosity.The questionthen becomes:Are there flows of interest in which the viscous effects are negligibly small? The answer is “Yes,if the shear stresses in the flow are small and act over such small areas that they do not significantly affect the flow field.”This statement is very general,of course, and it will take considerable analysis to justify the inviscid flow assumption.

A viscous flow can be classified as either a laminar flow or a turbulent flow .In a laminar floe the fluid flows with no significant mixing of neighboring fluid particles. If dye were injected into the flow,it would not mix with the neighboring fluid exept by molecular activity; it would retain its identity for a relatively long period of time .Viscous shear stresses always influence alaminar flow . The floe may be highly time dependent or be steady.

Incompressible gas flows include atmospheri flows, the aerodynamis of landing and takeoff of ommercial aircraft,heating and air-conditioning airflows, flow around automobiles and through radiators, and the flow of air around building, to name a few compressible flows include the aerodynamics of high-speed aircraft, airflow through jet engines, steam flow through the turbine in apower plant,airflow in a compressor, and the flow of the airgas mixture in an internal combustion engine.

When a temperature gradient in a body,experience has shown that there is an energy transfer from the high-temperature region to the low –temperature region.We say that the energy is transferred by conduction and that the heat-transfer rate per unit area is proportional to the normal temperature gradient.

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