混流式水轮机尾水管非定常流动模拟及不规则压力脉动预测

混流式水轮机尾水管内螺旋形涡带引起的压力脉动是造成混流式水轮机组振动的主要根源之一,严重威胁机组的安全运行.本文基于CFD技术对一大型混流式水轮机尾水管压力脉动进行了数字化预测,文中首先对该水轮机在典型偏工况下尾水管的内流进行了长时间非定常计算,然后详细讨论该工况下尾水管内死水域与涡带的运动规律,并预测了尾水管的不规则压力脉动,最后对压力脉动预测值进行了分析,结果表明其波形、频率、相位与实际基本一致,证明文中压力脉动的预测方法是可行的.

Simulation and pressure pulsation prediction of unsteady flow in draft-tubes of Francis turbine

For Francis turbines,the pressure pulsation in draft-tubes induced by helical vortex rope is one of the main problems and it would seriously affect the safe operation of the unit.This paper presents a numerical prediction of the pressure pulsation of a draft tube of Francis turbine based on CFD(Computational Fluid Dynamics) technology.After simulating the unsteady flow of a draft tube,the authors analyzed the unsteady flow behavior associated with irregular variation of the dead core and the vortex rope in the bent draft tube,and predicted the irregular pressure pulsation of the draft tube.The analysis result shows that the predicted wave shape,fundamental frequency and phase-shift of pressure pulsation agree well with measured data.