你可能感興趣的試題

The crankcase of many diesel engines are kept under a slight vacuum by the （）.

A.scavenging action of the piston
B.piston type vacuum pump taking suction off a differential manometer
C.gland exhausting manometer
D.crankcase exhaust fan

單項選擇題

Fins are installed on the generating tube surfaces in waste heat boilers to （）.

A.prevent soot fires in the exhaust system
B.prevent exhaust gas erosion of the tubes
C.increase the velocity of exhaust gas flow
D.increase the rate of heat transfer