T形三通管计算模型对尾水进口压力和调压室涌浪的影响

针对含尾水调压室的抽水蓄能电站,以特征线法和瞬变流理论为理论基础,在考虑尾水调压室长连接管水体惯性作用及管壁弹性的基础上,在T形三通管节点处分别建立了基于恒定局部水头损失系数、Gardel公式、试验资料的3种计算模型.结合工程实例,应用T形三通管节点处的3种计算模型对水电站的过渡过程进行了数值模拟;采用Gardel公式和试验资料,计算了过渡过程中不同时刻点的局部水头损失系数,研究了不同计算模型对尾水进口压力水头和涌浪水位的影响.结果表明:基于恒定局部水头损失系数的计算模型其阻抗作用最小,对应的尾水进口最小压力和最高涌浪最大;基于试验资料的计算模型其阻抗作用最大,对应的尾水进口最小压力和最高涌浪最小;基于Gardel公式的计算模型次之.

Influence of tee minor hydraulic loss model on draft tube inlet pressure and upsurge in surge chamber

Transient hydrodynamic flow in the penstock of a pumped storage power station with surge chamber was simulated numerically in the paper by using method of characteristic and by involving pipe elasticity and water body inertia. In the simulation, the pipe tee was considered as a computational node, the minor hydraulic loss across it was modelled respectively with a constant minor hydraulic loss coefficient, Gardel formula and experimental data. Influences of three models on the pressure at the draft tube inlet and upsurge in the surge chamber were identified. Results showed that the impedance based on the constant minor hydraulic head loss coefficient was the minimum, and the corresponding maximum upsurge and minimum pressure at the draft tube inlet were the highest. The impedance based on the experimental data was the maximum, and the corresponding maximum upsurge and minimum pressure were the lowest. The impedance based on the Gardel formula was in between. The conclusion can provide a reference for estimating maximum upsurge and minimum pressure at draft tube inlet in hydraulic engineering.