混流式水轮机部分负荷下尾水管压力脉动试验研究

通过三峡电厂升水位试验数据分析了混流式水轮机部分负荷下尾水管压力脉动主频的变化趋势，指出了目前两种用于计算尾水管涡带频率的适用性不足。试验数据表明，定水头下尾水管压力脉动主频在部分负荷低负荷段随着水轮机流量的增大有减小的趋势，在部分负荷高负荷段中呈“V”型分布，这种“V”型分布与尾水管固有频率相关；定导叶开度情况下，部分负荷下尾水管压力脉动主频与水头没有必然联系；试验同时表明，部分负荷下尾水管压力脉动对机组稳定性参数具有直接影响，是引起机组稳定性参数变化的主要原因。

Test Research on Francis Turbine Draft Tube Pressure Vibration in Partial Load

Francis turbine draft tube pressure fluctuation in partial load has been analyzed through field test data of Three Gorges Hydropower Plant. Inapplicability of two formulas to calculate the vortex frequency has been pointed out in certain turbine draft tube pressure fluctuation. In lower partial load, the test results indicated that in certain water head the main frequency of draft tube pressure fluctuation decreasing with the discharge increasing. In higher partial load the main frequency has the distribution of V type with the discharge varying, which may has the relation with draft tube inherent frequency. In certain guide vane angle, the results showed that in partial load the main frequency of draft tube pressure fluctuation had no definite relation with water head. Meanwhile, in partial load the draft tube pressure fluctuation had direct influence to unit stability. And the pressure fluctuation in draft tube was the main reason to stability parameter variation.