Three Dimensional Fluid Field Simulation And Structure Analysis Of Turbine Blade

Turbine blade which is operating under high temperature, high pressure and high rotation speed circumstance, is the key component of gas turbine. It bears thermal loads, aerodynamic load, centrifugal load and other complex cyclic load. In order to ensure the cooling system efficiency and the blade working life during operation, fluid field coupling simulation and strength analysis are urgent to be done.Conjugate heat transfer fluid field analysis and fluid structure interaction strength analysis have been done, which are based on a simple blade model with three cooling channels. The results from conjugate heat transfer fluid field analysis prove that the cooling efficiency using steam is higher than air. In addition, the results from this method can be used as thermal and aerodynamic loads for further strength analysis. Fluid structure interaction analysis results are closer to real situation because of considering the convection between blade and surroundings and the deformation of blade mesh grid in the same time. The blade structure meets strength conditions.Based on the boundary conditions of cooling channels and mainstream field, the fluid entity models for the binary-cooling turbine blade are established for further conjugate heat transfer fluid field analysis. The results include three-dimensional temperature, pressure, velocity field and all other data about flow field parameters. Through the analysis of flow field data, it is proved that the binary-cooling method which uses steam convection for internal cooling and air film for external cooing has higher cooling efficiency than traditional pure air cooling method. The binary-cooling method can reduce the blade surface average temperature by 20～50℃.Due to the complexity of turbine blade working environment, the thermal loads and aerodynamic loads are nonlinear and hard to specify. The three dimensional temperature field and pressure field from conjugate heat transfer simulation are relatively accurate simulations of the blade 3-D loading characteristic. Thus they are used as thermal loads and aerodynamic loads in static structure analysis in order to check the blade structure quality. The results show that stress concentrations mainly appear at blade root and the values around trailing edge are much bigger. And the analysis for another rotating blade with known three-dimensional temperature field data and tenon model indicates that, the blade basically meets strengths conditions and stress concentrations mainly appear around tenon tooth which is fixed and on suction side near tenon.