23.An ejector’s performance can be rated based on the ratio of the pressure at the discharge port
divided by the pressure at the suction port, referred to as the compression ratio. For the ejector with pressures at the discharge and suction ports of 2 and 0.5 bars, the compression ratio is . (A)1 (B)1.5 (C)2.5 (D)4
33.What is the temperature at which condensation of moisture begins when the air is cooled? It is the saturation temperature corresponding to the vapor pressure and relative humidity.
(A)Wet-bulb temperature
(B)Dry-bulb temperature
(C)Saturating temperature
(D)Dew-point temperature
34.What are the general considerations during the development of ship propulsion system? ①propulsive power requirement ②rotating direction of propeller ③main shafting system ④selection of propulsion engine
(A)①②③
(B)②③④
(C)①③④
(D)①②④
37.Which process can reduce the work required for multistage compression?
(A)Isentropic expansion
(B)Regenerative system
(C)Intercooling
(D)Reciprocating compression