基于CFD混流式水轮机减压板结构形式研究

为研究减压板结构对混流式水轮机转轮上冠流道的影响,以红山嘴一级水电站#4水轮机为例,基于CFD商用软件,数值模拟额定工况下水轮机泵板装置,以排水管压力为指标验证模型的准确性,并优化减压板半径及高度,分别从泄漏水流态、主轴密封真空度、顶盖排水管压力三方面进行对比分析。结果表明,改变减压板高度较改变半径对流道内部影响更大;随着减压板高度减小或半径增大,主轴密封真空度增大且顶盖排水管压力减小;不同减压板结构上冠流道流态不尽相同。该水轮机在减压板半径不变的基础上向上移动15mm为最佳方案,实际工程可通过减小减压板高度来提高主轴密封性能。

Research on Structure of Francis Turbine Pressure Reducing Plate Based on CFD

To study the influence of pressure reducing plate structure on upper canopy runner of Francis turbine, taking No.4 Turbine of Hongshanzui I Hydropower Station as an example, based on the CFD commercial software, the hydraulic turbine pump plate device was numerically simulated under the rated condition. The accuracy of the model was verified by taking the drainage pipe pressure as an index. Then, the radius and height of the pressure reducing plate were optimized, and comparative analysis was carried out from three aspects of leakage flow regime, vacuum degree of main shaft seal and top cover drain pipe pressure. The results show that the change of the pressure reducing plate height has more impact on the inside of flow passage than the change of the radius. As the height of the pressure reducing plate decreases or the radius increases, the vacuum degree of the main shaft seal increases while the pressure of the top cover drainage pipe decreases. The flow regime of the upper canopy passage is different for different pressure reducing plate structures. The best plan for the turbine is to move up 15 mm on the basis of the constant pressure reducing plate radius, and the sealing performance of the main shaft can be improved by reducing the height of the pressure reducing plate in the actual project.