One- and three-dimensional coupling flow simulations of pumped-storage power stations with complex long-distance water conveyance pipeline system

Abstract This study developed a one-dimensional and three-dimensional (1D–3D) coupling transient flow simulation method to investigate the effect of nonlinear fluctuations of pressures and hydraulic thrusts on the impeller and reveal their underlying flow mechanism during a combined operation mode, comprising two parallel pump-turbines, in a complex water conveyance pipeline system at an actual pumped-storage power station. Experimental verification suggested that the 1D–3D coupling method could accurately simulate the pressure fluctuations and rotational speed of the impeller. Additionally, three combined operation modes consisting of two parallel pump-turbines in a complex hydraulic pipeline system at an actual pumped-storage power station were simulated to test the performances of the developed 1D–3D coupling method. Test results suggested that the proposed method can successfully capture the nonlinear fluctuations of pressures and hydraulic thrusts on the impeller and water hammer phenomena. Additionally, it can reproduce the local and global backflow in the impeller, which induce fluctuations in the pressures and hydraulic thrusts. This study demonstrated that the 1D–3D coupling flow simulation method can provide more transient flow in a pumped-storage power station, possessing a complex long-distance hydraulic pipeline system, using lower computational cost than the conventional pure 1D and full 3D simulation method.