This paper introduces the 3D numerical simulation of unsteady turbulent flow in the entire flow passage of a water turbine model with CFD technology. A new and available method for the design of a Francis turbine has been explored. The boundary conditions have been implemented based on the 3D averaged N-S equations. The governing equations are discreted on space by the finite volume method and on time step by the finite difference method. The 3D unsteady turbulent flow in an entire Francis turbine model is calculated successfully using the CFX-TASCflow software and RNG k-εturbulence model. Transient flow fields are simulated in the spiral case, the distributor, the runner and the draft tube. It is presented in this paper that the computer simulation of the flow fields in components of the Francis turbine at the optimum operating condition. Meanwhile, the velocity and pressure at any points in the flow fields can be obtained so as to provide the great value on the performance prediction. According to the simulating results, the flow analysis and the design experience, the design of components in a Francis turbine model can be improved and optimized. In this way, designers may decrease numbers of test and shorten the period for a model. Therefore, the cost of research and produce can be reduced.
Unsteady simulation of cavitating turbulent flow for low head Francis turbine
