基于涡动力学的可逆转轮双向流动诊断及优化设计

为了诊断可逆转轮的三维流场,引入局部涡动力学诊断方法,从叶片对流体做功能力分析过流部件的设计状况。通过对沿流线的截面上总压流的分解,找到对总压流产生不良影响的动力学根源和位置。根据诊断结果,通过在设计中改变叶片的环量分布,对可逆转轮进行了改进,提高了转轮的效率和气蚀性能。可逆转轮数值实验结果表明:在水泵工况,改进前后的转轮效率分别为91.3%和92.1%;在水轮机工况,改进前后的转轮效率分别为91.9%和92.4%;改进后气蚀系数降低了0.012。

Bidirectional flow diagnosis to optimize the design of a pump-turbine runner using vorticity dynamics theory

The bidirectional flow in a pump-turbine runner was analyzed using a vorticity dynamics based method. In this method, the runner design is related to the work applied by the blade. The integral of the total pressure work normal to the streamline was analyzed to understand the variations of the pressure work with blade position and the effect of blade position on the total pressure work. The flow diagnosis results are used to modify the distribution of circulation to improve the efficiency and cavitation performance of the pump-turbine runner. Numerical experiments show that for the pump working condition, the runner efficiency is 91.3% and 92.1% before and after the improvement, while for the turbine working condition, the runner efficiency is 91.9% and 92.4% before and after the improvement and that the cavitation coefficient is reduced by 0.012 after the modification.