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.
reaction in the shaft
      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.

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