Abstract: In order to study the cavitating flow in a Kaplan turbine, the numerical simulation with a full cavitation model and a mixture two-phase flow model, which are in commercial code Fluent 6.1, has been performed to the unsteady cavitating turbulent flow within the whole flow passage of a Kaplan turbine in a hydraulic power plant. Based on the simulating results, the region and the degree of cavitation occurred in the flow passage of the turbine running in a given working condition are predicted, the energy performance of the turbine is also evalu-ated. The predicted cavitation phenomena coincide with those observed in the cavitation experiment to a corresponding model turbine. It shows that the numerical simulation results can pro-vide references for the running performance prediction of a Kaplan turbine.

Key words: Kaplan turbine, Numerical simulation, Unsteady cavitating turbulent flow, Whole flow passage