The Numerical Simulation Research And Pressure Pulsation Analysis In Francis Turbine

Hydro turbine is one of the important equipment of a hydropower station, and the Francis turbine is the most widely applied. In the present paper, with the model Francis turbine of a hydropower station as the research object and the computer as the test platform, the internal flow condition of the turbine is researched by the numerical simulation.First, the background and meaning of this research is discussed briefly, the four mainly means in the current research of the turbine flow is introduced, and the numerical simulation progress about the internal flow of the Francis turbine at home and abroad is reviewed.Next, the CFD fundamental principle involved is briefly introduced with the commercial CFD software FLUENT, the process approaches of the turbulent flow in numerical simulation is mainly analyzed, and the RANS model and its related fundamental principle is discussed specially.Then, with the combination of the features of the UGS NX and ICEM, the technology fusion of CAD/CFD is realized, and the basins of the volute, runner, and draft tube are meshed into the entire hexahedral structured grid, while the basin of water guiding is the mixed grid with the hex-core.Finally, the steady condition of the whole flow passages of the Francis turbine is numerical simulated with the RNG κ-ε turbulent model, and the computational results of each flow passage component is analyzed systematically, including the distribution of the velocity and pressure fields in the basins of the volute, runner, water guiding and draft tube, and with the unsteady numerical simulation based on the steady results, the change distribution of the pressure and the vortex in the draft tube are presented, and the pulsating characteristics is analyzed to further find the relationship between the different operating conditions and the fluctuation intensity.