弱辐射下光伏离心泵的流动计算与试验

在太阳弱辐射下,推导了光伏离心泵入口附近的冲击损失公式.分析了转速降低时二次流的部位和范围,并讨论了辐射的锯齿波动和有向持续改变对流场造成的影响.应用计算流体动力学Fluent软件,基于雷诺时均Navier-Stokes方程和标准k-ε湍流模型,考虑4种不同的辐射条件,采用SIMPLEC算法对设计的光伏离心泵进行计算,并通过试验进行验证.计算和试验结果表明,入口冲击损失主要取决于圆周速度平方;流场内会出现正反向交替的振荡脉动,产生压力扰动波和稀疏波;随着太阳辐射减弱,入口先出现冲击损失,然后变成与旋转方向相同的漩涡;出口扰动滞后于入口扰动,先发生在叶片背面附近,然后迅速向下一叶片压力面发展.

Flow calculation and experiment of photovoltaic centrifugal pump under weak radiation

The formula of inlet shock loss under week sun radiation was derived. The location and extent of secondary flow caused by speed reduction were analyzed. The effects of saw-tooth waving and continuous changing of radiation on the flow field were discussed. Based on Reynolds time-averaged Navier Stokes equation and standard k-ε turbulence model,a self-designed photovoltaic centrifugal pump was simulated by computational fluid dynamics software of Fluent and SIMPLEC method under four kinds of radiation and tested by experiment. The results of calculation and experiment show that the inlet shock loss is mainly determined by square of circumferential velocity. The forward and reverse alternated oscillation pulse in flow field can lead to pressure disturbance waves and rarefaction waves. With the radiation decreasing,the shock loss first appears at the inlet and gradually evolves into a whirlpool in the same direction of the rotation. The outlet disturbance lags behind inlet one. It occurs near the blade suction side first,and then develops to the next blade pressure side rapidly.