水动力学研究与进展B辑
水動力學研究與進展B輯
수동역학연구여진전B집
Journal of Hydrodynamics
2015年
4期
513-521
,共9页
左志钢%刘树红%刘德民%覃大清%吴玉林
左誌鋼%劉樹紅%劉德民%覃大清%吳玉林
좌지강%류수홍%류덕민%담대청%오옥림
interblade vortices%pressure fluctuations%Francis turbine%cavitation%Rayleigh instability
Interblade vortices can greatly influence the stable operations of Francis turbines. As visible interblade vortices are essentially cavitating flows, i.e., the ones to cause interblade vortex cavitations, an unsteady simulation with a method using the RNG k-εturbulence model and the Zwart-Gerber-Belamri (ZGB) cavitation model is carried out to predict the pressure fluctuations induced. Modifications of the turbulence viscosity are made to improve the resolutions. The interblade vortices of two different appearances are observed from the numerical results, namely, the columnar and streamwise vortices, as is consistent with the experimental results. The pressure fluctuations of different frequencies are found to be induced by the interblade vortices on incipient and developed interblade vortex lines, respectively, on the Hill diagram of the model runner’s parameters. From the centrifugal Rayleigh instability criterion, it follows that the columnar interblade vortices are stable and the streamwise interblade vortices are unstable in the model Francis turbine.