Simulation Of The Whole Passage In Prototype Turbine And Analysis Of Precision In Calculation

Because the reliability of predicting pressure fluctuations in prototype turbine is low by model test, and the result of CFD simulation based on the single flow passage or single flow component in hydraulic turbine, without considering the interaction of the components, shows much difference. Therefore, the simulation in whole passage is necessary.Firstly, three-dimensional steady simulation in whole passage of the prototype turbine is carried out in this paper and the energy performance and flow field characteristic is predicted. The result of simulation agrees well with the test data except some error in efficiency. The author supposes the reason of lower efficiency is the coarse grid. Then the simulation based on the single passage is carried out and the former suppose is confirmed. Based on this, the more deeply study was carried out through the single passage simulation considering the several factors affecting calculation precision including grid, turbulence model and discretization scheme. The adaptive grid type, the suitable grid scale adopted in different operation conditions, and the better turbulence model is suggested.In addition, three-dimensional, unsteady Reynolds-averaged Navier-Stokes equations were solved in the whole passage to investigate pressure fluctuations due to vortex rope at part load. The predicted results agree well with the prototype measurement and present some difference with the model test, which proves the three-dimensional unsteady simulation in whole passage can predict the pressure fluctuations in turbine well.