摘要
本文选取了一个弯肘形尾水管,保持肘管和扩散段尺寸不变,分别增加和减少尾水管直锥段的高度,形成3种高度的原尾水管、深尾水管和浅尾水管。结果表明,在典型部分负荷工况,浅尾水管使转轮出口与直锥段内的回流区增加,尾水管内的二次流强烈,力矩脉动较大,同时尾水管内流态紊乱,能量损失大,不易形成稳定的涡带,因此,尾水管管壁附近压力脉动幅值相对较小,频率成分丰富,但尾水管的回能效果差;深尾水管和原尾水管都表现出偏心涡明显,涡带运动稳定,尾水管压力脉动频率稳定等特点。但深尾水管的压力脉动幅值和对转轮力矩的影响都较原尾水管小。
The unsteady flowfield in three draft tubes with same inlet diameter ,e lbow,diffusion tube and different height were calculated.They are defined as lo w draft tube with a shorter cone,original draft tube with middling cone and dee p draft tube with a longer cone.Pressure oscillation in them under typical part_ load condition are compared and analyzed.The results show that in low draft tube there is a large reˉverse flowarea with strong vortices near runner outlet,wh ich has a great influence on runner moment;there is great energy loss in center p art of the cone so that it is not easy to form stable vortex rope,thus it gives different frequency components with lower fluctuation amplitudes near draft tub e wall;on the other hand,both original and deep draft tube show obvious eccentr ic vortex on cone section,stable vortex rope inside draft tube and fixed freque ncy in whole flow path;however,for deep draft tube the amplitudes of pressure oscillation and runner moment fluctuation are lower than those for original draft tube.
出处
《大电机技术》
北大核心
2004年第4期47-51,共5页
Large Electric Machine and Hydraulic Turbine
