不同工况下水泵水轮机尾水管压力脉动特性与改善措施研究

不稳定水流诱发的压力脉动是引起水力机械振动进而影响水泵水轮机安全运行的重要原因.为研究不同流量下水泵水轮机尾水管涡带形态的演变,分析空化系数对涡带形态的影响,基于FBM湍流模型,针对水泵水轮机五种典型运行工况进行非定常数值模拟,重点比较了不同流量与空化系数对尾水管涡带形态的影响.结果表明,当机组运行在0.5倍和1.1倍...

Research on Pressure Pulsation Characteristics and Improvement Measures of Pump Turbine Draft Tube under Different Working Conditions

The pressure pulsation produced by the unstable flow is an important reason for the vibration of hydraulic machinery,which in turn affects the stable operation of the pump turbine.In order to study the vortex rope evolution in pump turbine draft tube under different flow conditions and analyze the influence of cavitation coefficient on vortex shape,this paper selects five typical flow conditions to simulate unsteady flows in the pump turbine based on the FBM turbulence model,and the analysis focuses on the influence of different flow rates and cavitation coefficients on the vortex shape in the draft tube.The results show that cavitation has the most obvious influence on the 50%and 110%Q_r(Q_r:rated flow discharge)flow conditions.Further,the effects of vortex suppression grooves and diversion baffles on the internal flow pattern in the draft tube and the low-frequency pressure pulsation due to the vortex rope are investigated.It is noted that the vortex suppression grooves and diversion baffles can effectively improve the internal flow and pressure pulsation in the straight cone of the draft tube.