表面粗糙度对轴流泵性能的影响

Influence of wall roughness on performance of axial-flow pumps

【目的】探讨表面粗糙度与当量粗糙度之间的转换关系,研究在不同表面粗糙度条件下过流部件对轴流泵性能的影响。【方法】首先以圆管流动为研究对象,采用CFD数值模拟方法研究粗糙度对管道沿程损失的影响,通过数值计算结果与试验数据的对比,验证所建立的转换关系和所采用的数值计算方法及其相关参数的准确性和合理性;在此基础上展开某轴流泵在不同工况下过流部件粗糙度变化对其性能的影响研究。【结果】过流部件的表面粗糙度对轴流泵的水力效率和扬程有较大影响。最优工况下,与无粗糙度相比,粗糙度为3.2,6.3和12.5μm时,泵扬程分别下降0.3,0.5和0.7m,效率分别下降4.7%,5.7%和6.8%。【结论】建立了表面粗糙度与当量粗糙度之间的转换关系;通过研究粗糙壁面对管道沿程损失和轴流泵性能的影响,验证了CFD数值方法的可行性及准确性。

【Objective】The relationship between surface roughness and equivalent sand-grain roughness was investigated to understand the effect of surface roughness of flow component on pump performance.【Method】First,apipe flow is considered,and the influence of surface roughness on frictional loss along the pipe was studied by CFD method.The established relationship and adopted numerical method as well as the accuracy and reasonableness of related parameters were verified.Then,the effect of surface roughness of flow components on performance of an axial pump was examined at different operation conditions.【Result】The surface conditions of flow components had obvious influence on the hydraulic efficiency and head of axial flow pump.At the optimum point,compared to the case of no roughness,different surface roughness values of Ra=3.2,6.3and 12.5mcaused a reduction in head by 0.3m,0.5mand 0.7m,and a decrease in efficiency by 4.7%,5.7% and 6.8%,respectively.【Conclusion】The conversion between the surface roughness and equivalent roughness was established.Through the research on the effect of surface roughness on pipe frictional loss and the performance of axial pump,the feasibility and accuracy of the current CFD method were validated.