原型混流式水泵水轮机过渡过程中的压力脉动  

Transient pressure pulsations of prototype Francis pump-turbines

作　　者：杨建东[1] 胡金弘 曾威[1] 杨桀彬[1] 

机构地区：[1]武汉大学水资源与水电工程国家重点实验室,湖北武汉430072

出　　处：《水利学报》2016年第7期858-864,共7页Journal of Hydraulic Engineering

基　　金：国家自然科学基金重点项目(51039005)

摘　　要：电力市场日益增长的需求导致水泵水轮机频繁地改变运行工况,在偏离设计工况条件下,不得不历经压力脉动幅值较高的区域运行。混流式水泵水轮机的压力脉动主要由动静干涉、旋转失速以及尾水管涡带等不稳定流动引起的。然而,当前关于过渡过程中压力脉动的研究偏少,通常侧重于稳态运行。本文根据现场实测压力数据,采用Savitzky-Golay方法提取过渡过程中的压力脉动,并利用FFT、STFT等方法进行信号处理,揭示了实际抽水蓄能电站水泵水轮机甩负荷过程中压力脉动组成成分和相对强度变化的普遍规律。结果表明:蜗壳进口、无叶区在经过飞逸点后压力脉动将由高频的动静干涉和低频旋转失速共同组成,其动静干涉幅值极值分别出现在制动工况和飞逸点,旋转失速幅值极值均出现在飞逸点以后的制动工况。尾水管压力脉动组成频率则集中在低频区,与涡带和不稳定流态有关。The increasing need of electricity market leads to frequent switches of operating conditions forpump-turbines,which forces them to work in off-design conditions with high-amplitude pressure pulsations.Pressure pulsations for Francis pump-turbines are mainly caused by flow-induced instabilities such as rotorstator interaction, rotating stall and vortex rope in the draft tube. However, few researches concentrate onpressure pulsations in transient state compared with steady state. This paper presents a study of pressurepulsations of a prototype pump-turbine including steady state and transient state with pressure data mea-sured in spiral case,draft tube inlet and vaneless space in field test. Pressure pulsations are first obtainedwith Savitzky-Golay filter and then analyzed by FFT and STFT. The results indicate that when the turbinereaches runaway during load rejection,pressure pulsations in spiral case and vaneless space constitute rotorstator interaction with high frequency and rotating stall with low frequency. The maximum amplitude for ro-tor stator interaction occurs in turbine brake condition for spiral case and in runaway point for vanelessspace. The maximum amplitude for rotating stall occurs in turbine braking condition. Pressure pulsations indraft tube are made up of components with low frequency,which is in connection with vortex rope and un-stable flow.

关 键 词：水泵水轮机 过渡过程 压力脉动 信号处理 

分 类 号：TV734.1[水利工程—水利水电工程] TV743