14.下列何者不是離心泵流量降低之原因？ (A)濾器髒堵 (B)電流過高 (C)密封環間隙過大 (D)吸入管漏氣

10.Longitudinal vibration of propulsion shafting systems is often excited by the variable thrust developed by the propeller due to the non-uniform wake pattern in which it operates. The predominant periodic component of the thrust developed by a propeller occurs at blade-rate frequency, i.e., the number of propeller blades times the rotational frequency of the shaft. For a four-blade propeller running at 60 rev/min, what is the predominant periodic frequency that excites the longitudinal vibration of the propulsion shafting systems? (A)1 Hz (B)2 Hz (C)3 Hz (D)4 Hz

14.下列何者不是離心泵流量降低之原因？
(A)濾器髒堵
(B)電流過高
(C)密封環間隙過大
(D)吸入管漏氣

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