非定常流弯肘型尾水管不规则压力脉动预测

尾水管内螺旋状涡带引起的压力脉动是造成混流式水轮机机组振动的主要原因之一,直接威胁机组的安全运行。为此,提出一种基于CFD数值计算的水轮机尾水管压力脉动数字化预测法,并利用此法对一大型混流式水轮机偏工况下尾水管内水流流动进行了长时间非定常流计算,讨论该工况下尾水管内死水域与涡带的运动规律,预测了尾水管的不规则压力脉动,压力脉动分析结果表明,其波形、频率、相位与实际基本一致。

Irregular Pressure Pulsation Prediction for Elbow Draft Tube Unsteady Flow

For Francis turbine,the pressure pulsation produced by the helical vortex rope has become one of the main problems and seriously affects the safe operation of the unit.This paper put forward a digital prediction method of pressure pulsation based on CFD,and carry out a long time unsteady numerical simulation for a large Francis turbine under part load conditions,presented the unsteady flow behavior associated with the irregular variation of the dead core and the vortex rope in the bent draft tube,and predicted the dead core,the vortex rope and the pressure pulsation.The fundamental frequency and the phase-shift of pressure pulsation calculated supported the general knowledge based on the past experimental experience.