【摘要】 为了探讨水泵水轮机飞逸工况下无叶区高速水环形成机理以及对机组稳定运行的影响,以某抽水蓄能电站水泵水轮机模型为研究对象,采用Realizable k-ε湍流模型,通过数值模拟结合模型机进行实验,对全流道定常和非定常数值模拟计算,并与实验结果进行对比。结果表明:水泵水轮机S特性与飞逸点稳定性存在内在联系,飞逸工况下无叶区高速水环影响飞逸的稳定性;高速水环区周向速度分布以及反作用度分布存在极值点,其中周向速度在高速水环靠近转轮叶片一侧存在极大值,反作用度则在靠近转轮叶片一侧存在极小值,高速水环是引起无叶区水力损失的主要原因;飞逸工况下,随着开度的增加,高速水环越发不明显,小开度飞逸工况下,由于来流方向与叶片骨线存在较大冲角,致使转轮叶片进口端产生规律性的旋涡结构,而冲角随着流动变化浮动较大,存在较大随机性,高速水环是导致随机性波动的原因。更多还原

【Abstract】 Aiming to investigate the formation mechanism of high-speed water ring in the vaneless region and the effect on the stable operation of the unit under the runaway condition,the pump-turbine of one certain pumped storage power station was employed. Based on realizable k-ε turbulent model,the unsteady flow of the whole passage of pump-turbine was calculated. Some parameters such as the speed of the high-speed water ring were studied in bladeless zone. And comparing the numerical simulation results with the test,the results showed that there was an intrinsic connection between the S-shaped curve of the pump turbine and the stability of runaway operating. The value of fluid velocity in the bladeless zone was larger under the runaway condition. High-speed water ring in the bladeless zone under runaway conditions led to instability of running under the runaway condition,the high-speed water ring became more obvious with the decrease of the opening. Under small flow conditions,due to the large angle of attack between the incoming flow direction and the blade bone line,the vortex structure of the runner blade ends was regularly developed,and the angle of attack was increased with the flow variation. Vortex evolution was random and vortex evolution affected the change of blade angle of attack. The angle of attack varied greatly over time and there was great randomness. High-speed water rings were responsible for this random fluctuation.更多还原