Numerical Simulation Of Turbulent Flow Of Energy Dissipater In Free Flow Tunnel

As a water conveyance and discharging building, free flow tunnel is very commonly used in the hydraulic engineering. Some detrimental flow such as half pressure flow will appear when stream go through the tunnel. Therefore, it can improve stress condition, increase energy dissipation effect and reduce cost of construction to set up energy dissipater at inlet of a tunnel. It is very important to understand the flow flied in the energy dissipater in tunnel for determining the size and structure style of internal energy dissipation. Compared with model experiment data of the Jilintai hydropower station, a two-dimensional numerical model is developed to simulate the flow filed in energy dissipater in non-pressure tunnel by using the volume of flow (VOF) method and RNG k-εtwo equations turbulent model.The flow pattern and flow field in the energy dissipater in tunnel are simulated with the two-dimensional numerical model under different operating conditions. The non-structure grid is used for complex irregular boundary processing. An efficient algorithm PISO is used for the model and it can correct the bias of the mesh, so it can reduce iterative times. The flow pattern, energy dissipation ratio and velocity field are obtained. The calculated results are in good agreement with experimental data and provide the bases for optimal design of the energy dissipation in free-flow tunnel.