Numerical Simulation of Characteristics of Cavitation and Aeration in Free-flow Tunnel

摘要

Outlet structures were apt to occur cavitation damages with high speed flow, and aerators were usually adopted to reduce and eliminate cavitation damages in hydropower project. In this paper, the Realizable k-ε model and the Volume of Fluid method were used to simulate the characteristics of cavitation and aeration of the free-flow tunnel in Baihetan Hydropower Station. The distributions of water surface profile, pressure, flow velocity and cavitation number were gained. The results show that the Realizable k-ε model and VOF method were good at simulating the aerated flow of the free-flow tunnel. Aerators position is the main reason for the changes of velocity distribution in a cross section. The design parameters of the free-flow tunnel in Baihetan Hydropower Station are reasonable by the stable aerated cavities and the suitable length.