基于工质可压缩性的水泵水轮机驼峰初始工况导叶内部流动机理研究

Study on Internal Flow Mechanism of Pump-Turbine Guide Vane under Hump Initial Condition Considering Fluid Compressibility

摘要: 抽水蓄能系统在实现“双碳”目标方面具有重要意义，有利于与其他可再生资源相结合，形成环境友好型电力系统。水泵水轮机作为抽水蓄能系统的核心部件，驼峰区的形成会严重制约系统的安全性与稳定性，应予以考虑。此外，随着水泵水轮机向高扬程和大容量发展，工质的可压缩性变得不可忽略，不可压缩模型无法满足其高精度数值模拟研究的要求。针对这个问题，基于等温假设和Tait方程建立了一个弱压缩性模型，在这个模型的基础上对水泵水轮机内部的流场进行了数值模拟和分析。结果表明，考虑可压缩性计算出的驼峰曲线不仅与实验结果更加一致，而且还获得了更多的流动细节。对于近设计点的驼峰初始工况，虽然未考虑可压缩性和考虑后的结果皆表明导叶内部的流动结构引起的能量损失不容忽视，可压缩性对该流动结构发展还是比较显著的影响。

Abstract: Pumped hydrostorage systems take on a significance in fulfilling the “double carbon” goal, they are conducive to combined with other renewable resources to form environmental-friendly power sys-tems. The pump-turbine is the core component of the Pumped hydrostorage systems, in which the formation of hump region significantly restricts the safety and stability of the system that should be considered. Moreover, with the development of the pump-turbine to high head and large capacity, the compressibility of the working mass becomes non-negligible, and the incompressible model cannot meet the requirements of its high-precision numerical simulation study. For this problem, a weak compressibility model is built based on the isothermal assumption and Tait equation, the flow field inside the pump-turbine is simulated and analyzed base on this model. The results indicate that with considering the compressibility the calculated hump curve is not only more consistent with the experiment, but also it obtains more flow details. For the hump initial condition near the design point, although the results without and after considering compressibility show that the en-ergy loss caused by the flow structure inside the guide vanes cannot be ignored, compressibility still has a significant effect on the development of the flow structure.