网格对水轮机流动计算结果的影响

The effect of grid on the result of CFD simulation of turbine

在对混流式水轮机真机进行多个工况的全流道流动计算中发现计算得到的效率比试验参考效率偏低较多。为此,本文采用不同的网格类型和网格尺度分别对该水轮机的五个典型工况进行了单流道的数值计算。与全流道的计算结果以及试验的结果进行比较,分析了网格密度与计算的转轮效率的关系,并讨论了适合水轮机计算的网格类型,以及在一定的计算资源和不同的工况条件下,适合采用的网格尺度。

The result from the CFD simulation of the whole flow passage of a Francis turbine shows that the efficiency is underestimated under different operating conditions. To find the reasons, the flow field in single passage under five typical operating conditions is computed by using different grid types and densities. The computed results are compared with the test data. Then, the relations between grid density and numerical simulation efficiencies are analyzed. Finally, the proper grid type and density are suggested for CFD simulation of turbine under different turbine conditions with definite computing resources.