可调式射流泵内部流动与结构参数优化研究

Study on optimization of internal flow and structural parameters of adjustable jet pump

采用数值模拟研究了可调式射流泵的喷嘴距、喷针行程和流量比对其性能和效率的影响。喷嘴距较小时,射流泵性能较好,随着喷嘴距增大,由流体掺混引起的能量损失增大,导致整体效率降低。喷嘴距一定时,射流泵效率随流量比的变化存在峰值,即存在最佳流量比,且最佳流量比随着喷嘴距的增大而减小。射流泵内的压力比随着流量比增大呈线性衰减,衰减速度随喷针行程的增大而减缓;喷针行程增大时,射流泵效率明显降低,但最佳流量比的变化很小。确定了最佳工况参数为:喷嘴距约155mm,喷针行程1mm。

A simulation was carried out to study the effect of opening degree,nozzle spacing and flow rate ratio on the performance and efficiency of adjustable jet pump.The pump performs better in a lower nozzle spacing,because a higher nozzle spacing yields a larger energy loss induced by fluid mixing,which results in a lower pump efficiency.When the nozzle spacing stays constant,the curve of efficiency versus flow rate ratio shows a peak.The peak point denotes the optimal flow rate ratio and was found to be diminished by a higher nozzle spacing.The pressure ratio was revealed to linearly decline with the increase of flow rate ratio while the decreasing rate lowers down as the opening degree increases.The pump efficiency shows an apparent decline when the opening degree increases,while the variation of the optimal flow rate ratio is small.Under operating conditions in this work,the optimal nozzle spacing and opening degree of the adjustable jet pump were found out to be 155mm and 1mm,respectively.