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
A.Cross B.Parallel C.Counter D.Circular
A.remain constant along the tubes length B.be greatest in a single pass counter flow heat exchanger C.remain constant throughout the heat exchanger D.vary from section to section through out the heat exchanger