問題詳情
四、某離心式風扇的直徑為 1.00 m。該風扇以 600 rpm驅動密度為 1.00 kg/m3的空氣時，所需要的功率為 12 kW。假設效率不變，而該風扇改以 900 rpm驅動密度為 1.20 kg/m3的空氣，試求此時所需要的功率。（15 分）
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