試題詳解

14. In a centrifugal blower in coming air is directed into the eye of a rotating open, semiopen, or closed impeller that increases the air’s velocity and static pressure. After passing through the impeller, the air is often discharged radially through a stationary diffuser in which a portion of the velocity head is converted into static pressure head, and then through a tangential outlet port in the blower’s casing. Based on these descriptions, which is the correct statement?
(A) The conversion of flow kinetic energy into static pressure head takes place in the stationary diffuser.
(B) The enthalpy of discharged gas is reduced after passing through the centrifugal blower.
(C) The suction head for the centrifugal blower is automatically positive due to the eye of blower.
(D) The static pressure is reduced in the impeller but to be recovered in the eye of centrifugal blower.