乌江构皮滩水电机组水力稳定性试验研究

Experiment on hydraulic stability of hydro-turbines in Goupitan hydropower plant on Wu River

针对乌江构皮滩水电机组1#振动值超标,水电机组5#运行于高负荷区振动、水力不稳定等问题,进行了系统研究.采用工程测试软件Lab VIEW和美国国家仪器公司硬件对该问题制定测试方案,并对水电机组1#和5#进行了现场压力脉动试验.对试验结果进行处理分析,并根据试验分析结果推测水电机组产生不稳定性原因.针对可能的原因,采用相应处理方案对机组进行修型,最后进行试验验证.试验结果表明,水电机组1#将泄水锥由柱状改变为常规泄水锥,高负荷工况压力脉动严重的现象消失;水电机组5#对活动导叶出水边采取修薄处理,高负荷区振动轰鸣现象未消失,验证结果表明不是卡门涡引起水电机组5#高负荷区振动问题.研究结果对实际电站机组安全运行具有一定的指导意义.

A series of field experiments are carried out on hydro-turbine unit 1 and unit 5,respectively,in Goupitan hydropower plant to solve the problems such as too large vibration acceleration in unit1,vibration and hydraulic instability in unit 5 at high flow rates. In the prototype experiments,an advanced data acquisition software Lab VIEW and a testing program proposed by NI Hardware are adopted. The experimental results are processed and the reasons for the instability are inferred; subsequently,several measures are proposed,implemented and validated experimentally. It is confirmed that for unit 1 once the runner nut is changed into a cone from the original cylinder the severe pressure pulsation phenomenon disappears at high flow rates. For unit 5,however,even though the thickness of the trailing edge of wicket gate foils has been reduced,the severe pressure pulsation also persists,suggesting Karman vortex street is irresponsible for this effect. This outcome has a referential significance for safe operation of hydro-turbine units in a hydropower plant.