单项选择题
A.eliminate hot air from the condenser
B.maintain steady pressure in a system
C.heat, or cool one fluid by means of another fluid
D.reduce the engine room temperature in tropical climates
单项选择题 The temperature differential occurring between the inlet temperature of the fluid to be cooled and the outlet temperature of the cooling medium in a shell-and-tube heat exchanger is greatest in which of the flow designs listed?（）
单项选择题 The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.
单项选择题 If the relief valve on the discharge side of a hydraulic pump lifts, the cause could be （）.