潜水不恰当可能导致湿井内的水预旋转，导致形成强烈的自由表面空气中心漩涡，并使得空气进入泵的吸入进口管道。
Inadequate submergence can result in pre-rotation of the water in the wet-well, resulting in the formation of strong free-surface air core vortices and the entrance of air into the pump suction inlet.
设计了圆盘刀人力割禾器，其推进只是起到行走和预切割部分茎秆的作用，切割主要由动刀旋转来完成。
Disc sickle labor power cutter is designed which advanced attachment makes function as walking and precutting part straw, cutting finished by cutter section rotation.
该预旋角情况下，进气雷诺数对盘面平均努赛尔特数的影响大于旋转雷诺数。
The cooling flow rate have more effects on average nu number than rotating speed in this pre-swirl Angle.
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