离心泵进口回流诱导的空化特性

为了研究离心泵进口回流的空化特性,以IS65-50-160型离心泵为研究对象,首先选取CFX,Fluent和PumpLinx这3种模拟软件,应用标准k-ε模型,进行了网格无关性分析;其次,搭建了可用于外特性试验的开式试验台,将3种软件的外特性模拟值与试验值进行对比,分析3种软件在各工况下数值模拟的精确度;最后采用误差最小的模拟软件进行后续的空化和压力脉动数值模拟.结果表明:与其他2种数值模拟软件相比,CFX软件对小流量工况的模拟较为准确;由于回流的排挤作用加剧了主流区空化的发生;回流旋涡空泡的初生处于非附着状态,随着空化数的降低,最终附着在叶片上;回流旋涡空泡的发展和溃灭使得泵的特性曲线在急剧下降前出现了一段缓慢上升的趋势;在回流旋涡发生时,在叶轮进口以及叶片进口均出现了频率为9.7 Hz的低频脉动.

Cavitation characteristic induced by inlet backflow in a centrifugal pump

Cavitation characteristics induced by inlet backflow were studied in a centrifugal pump of type IS65-60-160.Numerical simulation were carried out firstly on the basis of standard k-ε model to analyze the independence of the grid number through three different kinds of CFD software such as CFX,Fluent and PumpLinx.Secondly,the open performance experiments were carried out to verify the accuracy of CFD software.Finally,the one with the was chose for the simulation of backflow vortex cavitation and pressure fluctuation.The results show that the hydraulic performance at low flow rate using the CFX code is more close to the experiment data as compared to the other two kinds of CFD software.The displacement effect of backflow increased the cavitation intensity around the mainstream region.Backflow vortex cavitation occurred at free state,and then developed attached to the blade.It shows a slight increase before head coefficient dropped sharply due to backflow vortex cavitation erosion and bubble collapse.The frequency of 9.7 Hz was found to be closely linked to the backflow vortex cavitation.