Numerical simulation of 3D flow in Francis turbine runner with X-type blades

Numerical simulation of large Francis turbine with X-type blades requires high-configuration computers. The results of numerical simulation and the demand of hardware resources are directly affected by the model and grids. The problem of large-scale flow computation is studied under limited hardware resource from the above two aspects. Two geometric models and three mesh scales are employed to simulate 3D turbulent flow in the Francis turbine runner with X-type blades. The hydraulic performance is predicted, and the flow details in the runner are analyzed. The results show that the performance features obtained by using single runner passage model are not only in good agreement with the experimental results, but also better than those obtained by using full runner model. The results also show that the pressure and velocity distributions on the surfaces of X-type blades are uniform, and the runner with X-type blades has good hydraulic performance. Numerical simulation with employing single runner model instead of full runner model can improve computing accuracy, save computing time, and reduce computing cost.