诱导轮内流场数值计算及汽蚀特性分析

Analysis of Cavitation and Flow Computation of Inducer

为得到诱导轮内部的速度场、压力场及湍流场的分布规律,在基于SIMPLEC算法上,采用了雷诺时均Navier-Stokes方程(简称N-S方程)控制方程和修正了的k-ε湍流模型,对两种结构参数的双叶片诱导轮进行了内部三维不可压湍流流动数值计算。计算结果表明诱导轮最容易发生汽蚀破坏的位置在进口外缘处,计算结果还表明增加诱导轮叶片轴向距离及导程有利于提高诱导轮的汽蚀特性。同时进行了不带诱导轮和带两种结构参数诱导轮的离心泵的外特性试验,试验结果表明离心泵在没有诱导轮的情况下较易发生汽蚀,而增加诱导轮能够明显改善离心泵的汽蚀性能,诱导轮的导程、叶片轴向长度、及其叶尖包角几何参数值等几何参数对汽蚀性能有较大影响。结合流场数值计算结果和试验研究结果,证实了通过增加轴向距离和导程等合理改变结构参数可提高诱导轮的汽蚀性能。

In order to obtain the distributions of velocity,pressure and turbulence in inducers,on the basis of SIMPLEC algorithm,the 3D turbulent flow in inducers of two structures is numerically computed by using the time-averaged N-S equation and the modified k-ε turbulent model.The calculation result proves that the outer margin near the inlet is where cavitation damage most easily takes place.The result also shows that increasing the lead and the axial length of inducer can improve the suction performance.The performance of cavitation tests in the centrifugal pump with an inducer of two different structural parameters and without an inducer are carried out.The result shows that the pump is easy to have cavitation without the inducer,and the cavitation performance can be improved by adding inducer.The parameters of inducer lead,axial length and the blade angle will influence the cavitation performance.Results of numerical calculation and experimental research prove that increasing the lead and the axial length of inducer can improve the suction performance.