更多"In practice, the refrigerant flow a"的相关试题:
[单项选择]If cooling water flow through the after-cooler is interrupted,the power output of a turbocharged diesel engine will drop because the （）
A. turbocharger will stall
B. density of the air charge will decrease
C. scavenge effect will increase
D. exhaust pressure will increase
[单项选择]The saturation temperature of the refrigerant must be （） that required in the evaporator refrigerated space.
A. above
B. below
C. equal to
D. None of the above
[单项选择]Insufficient refrigerant in a refrigeration plant may result in （）.
A. high discharge pressure
B. frosting of the crankcase
C. high temperature of the overboard water
D. low suction pressure of compressor
[单项选择]Refrigerant is circulated through a refrigeration system by the （）.
A. compressor
B. condenser
C. expansion valve
D. evaporator
[单项选择]Moisture in the refrigerant may （）.
A. freeze on the expansion valve seat and reduce the flow of liquid refrigerant
B. emulsify the oil in the condenser
C. freeze in the king valve
D. clog the oil trap
[单项选择]If liquid refrigerant accidentally comes in contact with the eyes, （） immediately.
A. rub the eyes
B. irritate the eyes
C. wash the eyes with a heavy boric acid solution
D. obtain medical help
[单项选择]The boiling and condensation points of refrigerant mainly depend on the （） exerted upon it.
A. temperature
B. density
C. volume
D. pressure
[单项选择]Refrigerant entering the compressor of a refrigeration system should be in which of the following conditions?（）
A. Sub-cooled liquid
B. Sub-cooled vapor
C. Superheated vapor
D. Liquid
[单项选择]Ammonia when used as a refrigerant is valuable because of its high efficiency, it is however （）.
A. toxic
B. flammable
C. explosive
D. all of the above
[单项选择]Compensated flow control or constant flow valves are used in hydraulic systems to（）
A. compensate for major leaks in the system
B. maintain the original fluid viscosity
C. allow for changes in pressure and temperature within the system
D. assure constant fluid temperature
[单项选择]As the refrigerant passes through the valve orifice, its pressure is reduced and part of the refrigerant turns into （）.
A. liquid
B. oily mixture
C. emulsion
D. vapor
[单项选择]The refrigerant leaves the evaporator of a refrigeration system as a low pressure （）.
A. sub-cooled liquid
B. high temperature liquid
C. oil saturated liquid
D. superheated vapor
[单项选择]The refrigerant gas returning to the compressor should be （）.
A. superheated
B. saturated
C. dense
D. flooded
[单项选择]The refrigerant flows through the evaporator, where it （） heat from the refrigerated space.
A. extracts
B. releases
C. gives no
D. absorbs no
[单项选择]In a refrigeration system, the refrigerant absorbs the latent heat of vaporization in the（）.
A. compressor
B. condenser
C. receiver
D. evaporator
[单项选择]When the temperature of the refrigerant flowing out from the condenser is below the condensing temperature, it is said to be （）.
A. dry
B. wet
C. super-cooled
D. superheated
[单项选择]Under normal conditions, the refrigerant enters the compressor in an operating refrigeration system as a （）.
A. liquid
B. dry saturated gas
C. wet saturated gas
D. superheated vapor
[单项选择]A pressure drop through the refrigerant liquid line may cause （）.
A. solenoid valve to seize
B. compressor to hunt
C. formation of flash gas in the liquid line
D. expansion valve to freeze open
