诱导轮叶片后倾角对高速泵空化性能及诱导轮内部能量转换的影响

Effect of Inducer Blade Dip Angle on Cavitation Performance of High Speed Pump and Internal Energy Conversion of Inducer

为研究高速变螺距诱导轮叶片截面在子午面的后倾角变化对高速离心泵空化性能及内部能量转换的影响,采用数值计算与试验相结合的方法,在叶片截面子午面内的几何形状参数不变的情况下,通过改变高速诱导轮叶片截面在子午面内的后倾角度,设计4组诱导轮方案。通过数值计算与试验结果分析对比发现:当诱导轮叶片截面在子午面内的后倾角在一定范围内增大时,高速离心泵的空化性能会得到改善;当叶片截面在子午面内的后倾角超过一定范围时高速离心泵的空化性能反而会降低;诱导轮叶片截面后倾角的变化会改变诱导轮进口轮缘轮毂的安放角,改善冲角与叶片进口安放角的匹配,抑制叶片入口轮缘处空化的发生;叶片后倾角对泵的外特性影响很小,说明改变诱导轮的叶片截面后倾角对叶片做功能力基本无影响;诱导轮的空化状态会影响诱导轮的能量转换,空泡附着在诱导轮叶片上会降低叶片的做功能力,通过相同空化数下不同诱导轮流道横截面上的总压分布,空化性能最好的方案中能量转换越好。

In order to study the effect of the high-speed variable pitch inducer blade section dip angle on the cavitation performance of the high-speed centrifugal pump and internal energy conversion of inducer,the method of combining numerical calculation and experimental verification is adopted.In this study,the shape geometry of the blade section in the meridian plane is not changed,and only the blade dip angle is changed.Four kinds of inducer schemes are designed for the dip angle of the blade section in the meridian.The results show that the cavitation performance of the high-speed centrifugal pump is improved when the dip angle of the inducer blade section in the meridian plane increases within a certain range,but the high-speed centrifugal pump has a decline when the dip angle of the blade section exceeds a certain range.And the change of the dip angle of the inducer blade section will change the blade angle of the rim and hub of the inducer inlet,and improve the matching of the attack angle with the inlet blade angle,and inhibit the occurrence of cavitation at the inlet rim of the blade.But the influence on the external characteristics of the pump is very little.This indicates that the changing of the dip angle of the inducer blade section has little effect on the functioning ability.At the same time,the cavitation state of the inducer affects the energy conversion of the inducer,and the attachment of the bubble on the inducer blade reduces the functional ability of the blade.By comparing the total pressure distribution on the cross section of different inducer passage under the same cavitation number,the better the energy conversion is in the scheme with better cavitation performance.