The Computional Fluid Dynamics Simulation And Research Of3D Flows In Whole Flow Passage Of Bulb Turbines

At present, a number of large and medium-sized hydraulic turbine runner blade cracks or appear in succession, the stability of the hydraulic turbine has become a prominent problem in operation and design. With the application of computer to continuously improve the level and the advancement of CDF technology for hydraulic turbine runner, three-dimensional simulation calculation has to be simulated guide vane wheel and wheel and tail pipes, noise interference, and can predict the performance of hydraulic turbine cavitation and pressure pulsation. So, the3-D turbulent flow field calculation of bulb tubular turbine runner and hydraulic turbine solid-liquid two-phase flow simulation and performance prediction, has important significance to improve the efficiency of the turbine and stability. This article on turbine flow field analysis of fluid dynamics (CFD) carried out into system research.First introduced the research purpose and meaning of the topic, and then to the current domestic and foreign turbine application present situation as the background, the significance of this study are discussed, and finally introduces the research methods, to help the study of internal flow of fluid machinery.Using UG software of hydraulic turbine parts of mathematical modeling, the structure model into workbench DM extraction channel, then the channel model into ICEM-CFD software painting hexahedral and tetrahedral unstructured grid, and interface each channel grid connected to form the whole flow passage of the hybrid grids.The generated grid input to ansysl2.0in the fluent to do analysis and calculation of the flow field. Select fluent in the RNG model using MRF multiple reference frame model of unsteady simulation. Be unsteady calculation flow trajectories, the pressure field, velocity field, velocity vector. steady computational data exchange to unsteady calculation, without the use of initialization, continue to compile the UDF function input wheel rotation speed, setting the dynamic mesh model, so that the runner at a fixed speed of rotation, and then calculated in a wheel rotation cycle, the full passage wall surface pressure versus time profile.At the rated operating basis, application of multiphase flow model of turbine flow field of solid-liquid two-phase flow simulation calculation of liquid phase and solid phase, respectively, the volume fraction of, velocity distribution diagram is used to analyze the hydraulic turbine cavitation and sand abrasion. The simulation results and practical power station wear consistent.The bulb tubular turbine machine as the research object, the use of CFD fluid dynamics analysis method on hydraulic turbine runner of three-dimensional numerical simulation, on the internal water flow mechanism of in-depth analysis, focusing on the runner and guide vane vortex interference problem, caused by pressure pulsation on the unit stability influence. We should guide and working parts of design optimization according to the actual situation of hydraulic turbine, adjustment of wheel placement and inlet angle, thereby improving the efficiency of turbine and stability.