单项选择题
Which of the following descriptions best identifies the operating principal of a flash-type evaporator?（）
A.Sea water is heated to boiling temperature while under a vacuum
B.Sea water is passed over heated plates in a thin film
C.Heated sea water is injected into a vacuum chamber
D.Sea water is forced through a heated eductor
相关考题
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单项选择题
Which of the listed conditions can lead to cavitation气穴in a centrifugal pump?（）
A.Vapor pockets formed in the suction flow stream
B.Rough easing volute surfaces
C.Worn wearing rings
D.Heavy fluid in the flow stream -
单项选择题
A centrifugal bilge pump requires priming （）.
A.primarily to lubricate the shaft seals
B.due to the inability of this type of pump to lift water to cover the suction (eye) of the impeller
C.to initially unload the pump by having its head pressure equal to discharge pressure
D.in order to overcome the potential energy of water in the discharge line -
单项选择题
The process of removing moisture from air is known as（）.
A.humidification
B.dehumidification
C.vaporization
D.evaporation
