单项选择题
A.central air conditioning system B.high velocity system C.low velocity system D.single duct system
The（） only allows for adjustment of temperature in each...
单项选择题The（） only allows for adjustment of temperature in each room by the occupant manually controlling the air volume admitted.
A.central air condition system B.high velocity system C.low velocity system D.single duct system
The volute of centrifugal pump also acts as a diffuser ...
单项选择题The volute of centrifugal pump also acts as a diffuser converting （）into pressure head.
A.mechanical energy B.heat energy C.potential energy D.kinetic head
A centrifugal impeller consists of a number of vanes cu...
单项选择题A centrifugal impeller consists of a number of vanes curving （） from the direction of rotation.
A.backwards B.forwards C.upward D.downwards
