叶片包角对水轮机模式多级液力透平性能的影响

Influence of blade wrap angle on performance in T-mode multistage hydraulic turbine

为了研究叶片包角对水轮机模式液力透平性能的影响,以1台二级透平为研究对象,分别设计转轮叶片包角为20°,30°,40°和50°,采用Fluent软件进行数值计算.结果表明:叶片包角对透平水力性能影响显著,随着包角的增大,透平水头逐渐升高,效率先增大后减小,设计工况下,当包角为30°时效率最高,达到80.24%.受一级转轮出口负环量的影响,二级转轮进口环量低于一级转轮进口环量,从而导致二级转轮效率比一级转轮效率低.通过对其压力脉动特性分析发现,转轮内的压力脉动较其他过流部件脉动强度大,二级转轮内的压力脉动最强,适当的包角取值能够降低各过流部件的压力脉动幅值.针对包角为30°的透平进行试验,数值计算结果与试验结果性能曲线变化趋势一致,验证了数值模拟结果的准确性.

In order to study the influence of blade wrap angle on the performance of hydraulic turbine,taking a two-stage turbine as the research object,the runner blade wrap angles were designed as 20°,30°,40°and 50°,respectively,and the Fluent software was used for numerical calculation.The results show that the blade wrap angle has a significant effect on the turbine hydraulic performance.With the increase of the wrap angle,the turbine head increases gradually,and the efficiency first increases and then decreases.Under the design condition,when the wrap angle is 30°,the efficiency reaches 80.24%.Due to the negative circulation of the primary runner,the import circulation of the secondary runner is lower than that of the primary runner,resulting in the lower efficiency of the secondary runner than that of the primary runner.Through the analysis of the pressure pulsation characteristics,it is shown that the pressure pulsation intensity in the runner is higher than that in other flow passage parts,and the pressure fluctuation in the secondary runner is the strongest.The appropriate value of the wrap angle can reduce the pressure fluctuation amplitude of each flow passage component.For the turbine with 30°wrap angle,the numerical simulation results are consistent with the test results,which verifies the accuracy of the numerical simulation results.