叶片厚度对轴流泵性能影响及内部流场分析

为研究叶片厚度对轴流泵性能影响及其内部流场变化规律,该文采用圆弧法和流线法进行比转速550、转速2900r/min的QY90-4.4-1.5型潜水轴流泵水力模型设计,完成产品开发及样机型式试验。通过加厚叶轮叶片进行对比试验,阐明泵流量—扬程、流量—轴功率和流量—效率曲线产生差别的原因。采用计算流体动力学(CFD)方法进行叶片厚度对流场影响的数值计算,得到最优工况叶片表面相对速度分布和不同工况叶片表面静压分布。经过分析,阐明薄叶片总体性能优于厚叶片,但抗汽蚀性能可能劣于厚叶片。厚叶片翼型脱流、叶片进出口出现回流及二次流情况更为严重,水力损失较大,是泵效率等性能参数偏低的主要原因。

Effects of blade thickness on performance of axial flow pump and analysis of internal flow field

In order to investigate the variable-thickness performance of blade in a axial flow pump,a QY90-4.4-1.5 submersible axial flow pump with specific speed 550 and rotate velocity 2900 r/min,especially its particular impeller and guide vane has been designed on the basis of arc method and streamline method.Based on experiments with increasing in leaf thickness,the reason about the difference among curves of q v-H,q v-P,q v-η were studied.The three-dimensional internal flow with effect of impeller blade thickness within axial flow has been numerically simulated by CFD,both the relative velocity distribution on the optimal condition and static pressure distribution on the different condition of blade surface were obtained.It can be revealed that pump performance with thin blade was improved,but the anti-cavitation was reduced.It also can be showed that the situations of flow separation,backflow and secondary flow were more serious for the thick blades,which were the main reasons for the low efficiency of pump.