混流式水轮机活动导叶动态绕流特性研究

摘要

为探索混流式水轮机活动导叶调节时,叶后非均匀流场的分布特性,应用非定常不可压缩流体N-S控制方程和基于亚格子湍动能的大涡模拟湍流模型,数值模拟某试验模型水轮机在进口速度攻角连续改变时活动导叶动态绕流特性。计算结果表明,随着进口速度攻角的逐渐增加,导叶诱发的涡结构强度逐渐增加,同时导叶尾迹区内各流向断面压力、速度以及涡量分布的不均匀度指标也逐渐增加。计算成果对优化水轮机设计具有重要的参考价值。To investigate the non-uniform characteristics of flow around a guide vane of Francis turbine, three-dimensional turbulent flow in full flow passage of a guide vane of a test Francis turbine model was simulated using large eddy simulation with dynamical subgrid-scale models based on turbulent kinetic energy. The dynamical characteristics about flowing distribution of the full guide vane passage at different inlet ve-locity attack angle are obtained. The numerical results show that the intense of vortices increases with the ris-ing up of the inlet velocity attack angle, simultaneously, the non-uniformity indexes about pressure, velocity and vorticity also increase. These findings are helpful to improve the design of the hydro-turbine units.