실험계획법(2 k 요인시험)을 활용한 날개각의 변화가 엇회전 펌프수차의 효율에 미치는 영향에 관한 연구

This paper reports the efficiency of a counter-rotating pump-turbine with various blade angles. Three-dimensional steady Reynolds-averaged Navier-Stokes equations with the shear stress transport turbulence model were discretized by the finite volume method and solved on hexahedral grids to analyze the flow in the pump-turbine unit. The numerical results for the pump and turbine modes were verified by a comparison with their experimental data. The blade angles at both the hub and shroud of the counter-rotating impeller/runner were employed as geometric parameters to investigate their effects on the efficiency of the counter-rotating pump-turbine. The main effects on the efficiency of the geometric parameters were analyzed from their interaction through the 2k factorial design method. These results showed remarkable increases in both the pump and turbine efficiencies compared to the reference model.