Experiment and Numerical Simulation on Hydraulic Loss and Flow Pattern of Low Hump Outlet Conduit with Different Inlet Water Rotation Speeds

Abstract

The rotation speed of water at the inlet of the low hump outlet conduit has a great effect on its hydraulic performance. Therefore, the influence of different inlet water rotation speeds on hydraulic loss and flow pattern of low hump outlet conduit is studied in this paper. By solving RANS equations and the RNG k-ε turbulence model, the hydraulic loss and 3D flow field of the low hump outlet conduit were calculated under different inlet water rotation speeds. To verify the numerical results, the model tests of low hump outlet conduit with different guide vanes were conducted. The results show that along with the growth of inlet water rotation speed, the hydraulic loss of outlet conduit will firstly decrease by degrees and then increase dramatically, the vortex location moves from the whole bottom of the descent segment to the right bottom of descent segment and the vortex area becomes smaller, the flow pattern of the whole conduit is improved obviously. The hydraulic loss and flow field of numerical simulation are consistent with those of the model test. Because of its great influence on hydraulic performance, inlet water rotation speed must be taken into consideration in the hydraulic optimization design of guide vane and low hump outlet conduit.