脫葉現象 的英文怎麼說
中文拼音 [tuōyèxiànxiàng]
脫葉現象
英文
defolation-
First super - low specific - speed centrifugal pump has a long and narrow flow passage for its high head and low capacity, and the power absorbed by disc friction is too high, so the efficiency is very low ; secondly the diffusion of flow passage is so high, that the reserved flow often emerges at the inlet and outlet of impeller. therefore the h ~ q characteristic curve is often hump - shaped, and at the low - capacity operating condition the instability often occurs ; thirdly the centrifugal pump at high - capacity operating condition is easy to overload because the n ~ q curve appears a rising trend
首先由於它的揚程較高、流量較小，所以它的流道狹長，圓盤摩擦損失較大，效率相對較低；其次由於它的流道擴散較嚴重，易在葉片進口產生迴流和在出口產生脫流，揚程流量特性曲線易出現駝峰，在小流量工況下易產生不穩定現象；第三，由於其功率流量曲線呈現上升趨勢，在大流量區運行時電機易過載。With the phenomena of dropping flow, backflow and secondary flow effected by circulation and surface curvature, the centrifugal pump ' s inner flow is very complicated 3d flow. therefore, the centrifugal pump inner flow is one of the difficult problems both in testing research and numeric computation
離心泵葉輪的內部流動是很復雜的三維紊流流動，同時由於受旋轉和葉片表面曲率的影響還拌有脫流、迴流及二次流的現象，是流體工程中較難的試驗研究和數值計算問題之一。
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