混流式水轮机大负荷区压力脉动陡升问题研究

Research on pressure pulsation jump of Francis turbine at full load zone

针对电站水轮机出现的大负荷区压力脉动陡增现象,通过电站模型和电站实测压力脉动实验结果,结合电站分步骤改型措施和对水轮机CFD结果分析认为,水轮机大负荷区压力脉动陡升问题与转轮叶片进口设计有直接关系,不理想的转轮叶片进口设计会导致水轮机在大负荷时叶片进口正面脱流,产生水轮机压力脉动陡升现象。在实际中可以通过改善水力和其它方法消除或减小水轮机压力脉动值,提高机组运行的安全稳定性。

The unstable phenomenon of Francis turbine under full load operating condition appears recently. On basis of the model test results, site test results and CFD analyses, it is determined that the unstable phenomenon is directly related to the runner blade inlet angle, because the improper hydraulic design may induce vortex at runner blade inlet pressure side. By improving the runner blade inlet design and other several solutions, the vibration amplitude can be reduced and then the unit operating condition can be improved.