两机一洞尾水调压室阻抗损失系数模型试验研究

Experimental Study of Impedance Coefficient for Tailwater Surge Chamber with Two Generating Units and One Tailwater Tunnel

水电站引水发电系统中调压室的阻抗损失系数是影响机组过渡过程计算结果的重要因素,目前阻抗损失系数一般在行业规范推荐的范围内进行取值,往往与试验值有所偏差,不利于调压室体型的优化设计。通过采用大比尺的调压室水工模型,对两机一洞型式的水电站阻抗式尾水调压室进行大流量条件下的水力学试验,研究不同水流流态和分流比对调压室阻抗损失系数的影响,分析控制工况下调压室的流入和流出阻抗损失系数,给出了调压室阻抗损失系数与分流比的拟合公式和关系曲线。研究结果填补了两机一洞型式的水电站尾水调压室阻抗损失系数试验的空白,可为此类调压室的水力计算分析提供依据。

The impedance loss coefficient of the surge chamber in the hydropower plant diversion system is an important factor affecting the calculation results of the transition process.At present,the impedance loss coefficient is generally taken within the range recommended by the industry specification,which often deviates from the test value and is not conducive to the optimal design of the surge chamber.Through large scale hydraulic model test of the surge chamber,this paper studied the effect of different flow patterns and flow diversion ratios on the impedance loss coefficient of the surge chamber,analyzed the inflow and outflow impedance loss coefficients of the surge chamber under the control condition,and proposed the fitting formula and relationship curve between the impedance loss coefficient and the diversion ratio.The study fills the gap of impedance loss coefficient test of tailwater surge chamber of two generating units and one tailwater tunnel type hydropower station,which can provide the basis for hydraulic calculation analysis of such surge chamber.