多机一室长廊型调压室水力过渡过程数值仿真研究

基于调压室基本方程和结构矩阵法,构建了典型的多机一室长廊型调压室—三联调压室水力过渡过程计算的恒定流模型和瞬变过程模型(简称三联模型),并基于工程实例,针对典型工况,分别采用简化模型和三联模型进行过渡过程计算。结果表明,简化模型和三联模型计算所得的蜗壳末端最大压力、机组转速最大上升率和调压室极值水位基本一致,而尾水管进口最小压力有一定的区别;采用三联模型可较好地反映恒定流状态下阻抗孔口之间的水体流动及过渡过程中尾水管进口压力的变化情况;过渡过程计算中阻抗系数取值允许一定的误差,并不会对尾水管压力和调压室水位的变化产生较大影响。

Numerical Simulation Study on Hydraulic Transient in Hydropower Station with Multi-turbine Shared Corridor-shaped Surge Tank

A static and dynamic model for the hydraulic transient simulation calculation of three-throttled-orifice surge tank (a typical kind of multi-turbine shared corridor-shaped surge tank) was established based on the basic equation and structure matrix method. Control conditions in a practical project were calculated by the simplified model and the three-throttled-orifice model, respectively. The results show that the maximum pressure at the volute end, the maximum rising rate of unit speed and the extreme water level of the surge tank are almost the same by using the two models, but the minimum pressure at draft tube inlet is different. Moreover, in three-throttled-orifice model, the flow in the throttled orifices at constant flow state and the pressure at draft tube inlet during the transition were calculated accurately. Resistance factor is allowed to have a certain error in the transition calculation, which will not cause great impact on the maximum pressure of the draft tube and the extreme water level of the surge tank.