带长连接管的调压室水力特性研究

Research on Hydraulic Characteristics of Surge with Long Connecting Pipe

某抽水蓄能电站下游调压室采用阻抗+上室式布置,尾水洞与连接管通过直角岔管和弯道连接,布置型式特殊,水流条件复杂。为研究其水力特性,建立了调压室底部连接管三维流场数学模型,研究了不同分流比、汇流比条件下水力特性的变化规律。结果表明,对于底部流动复杂的调压室阻力损失而言,三维数值模拟能取得较好的仿真效果,计算结果与理论分析结果吻合良好。由于调压室底部弯管、连接管与大井之间的突扩、突缩等均会引起额外的水力损失,其水头损失系数大于常规阻抗调压室,流量系数较单独的阻抗孔更小。

The downstream surge chamber of a certain pumped storage power station adopts impedance with upper chamber layout.The tailrace tunnel is connected with the connecting pipe through right angle bifurcated pipe and bend.The layout type is special and the water flow conditions are complex.In order to study its hydraulic characteristics,a three-dimensional flow field mathematical model of the connecting pipe at the bottom of the surge chamber was established,and the variation law of hydraulic characteristics under different diversion ratio and confluence ratio was studied.The results show that for the resistance loss of surge chamber with complex bottom flow,the three-dimensional numerical simulation can achieve better simulation effect,and the calculation results are in good agreement with the theoretical analysis results.Because the elbow at the bottom of the surge chamber,the sudden expansion and contraction between the connecting pipe and the big well will cause additional hydraulic losses,its head loss coefficient is greater than that of the conventional impedance surge chamber,and the flow coefficient is smaller than that of the separate impedance hole.