Verification And Application Of Complex Turbulence Models In Turbomachinery

With the rapid development of computer technology,computational fluid dynamics(CFD)technology has become an important means to study the internal flow of impeller machinery.The numerical simulation of the internal flow of turbomachinery is mainly based on the method of solving the Reynolds average Navier-Stokes(RANS)equations,and it is necessary to select the appropriate turbulence model to close the equations.Previous studies have shown that the choice of turbulence model has a great impact on the accuracy of numerical results.In this paper,five different turbulence models are applied to the numerical simulation of turbomachinery to verify the calculation accuracy and flow field information capture capability of different turbulence models in turbomachinery.At the same time,studies and analyzes the effects of turbulence model on the mechanical and aerodynamic characteristics and flow field characteristics of turbomachinery.Firstly,develops a set of grid processing program using Fortran to process the multi-block structured grid generated by NUMECA's Autogrid5 module,so that the processed grid can be directly used in the CFL3D solver developed by NASA Langley Research Center.At the same time,develops post-processing programs to display the calculated results by Tecplot software.Finally,combines the pre-processor,the solver and the post-processor to build the turbomachinery numerical calculation platform CFL3D_Turbo.Based on the CFL3D_Turbo to perform case study.Compares the calculated results of CFL3D_Turbo with the calculated results of NUMECA,and it is verified that the CFL3D_Turbo numerical calculation platform can better simulate the internal flow field of turbomachinery.Then the B-L model,S-A model,SST k-?model,Chien k-?model and k-?-R_t model are respectively applied to the numerical simulation of the flow field of the Durham compressor plane cascade.Studies and analyzes the effects of different turbulence models on the flow field distribution and the accuracy of the calculation results and their differences.The results show that the CFL3D_Turbo numerical calculation platform can better simulate the internal flow field of the plane cascade,the Chien k-?model has the worst calculated accuracy,and the k-?-R_t and S-A models have higher calculated accuracy.And the computational stability and convergence of the S-A and SST k-?models are relatively better,while the Chien k-?model is the worst.Finally,carries out the numerical simulation of the NASA rotor37 transonic axial compressor rotor,and analyzes the effects of different turbulence models on the flow field and the differences between the calculated results of the program and the experimental values in detail.The results show that the CFL3D_Turbo numerical calculation platform can better reflect the internal flow field of the rotor.The calculated error of the B-L model is the largest and the capture of the shock of the flow field is not accurate enough.The Chien k-?model has the worst convergence,and the SST k-?and k-?-R_t models have worse computational stability,while both the B-L and S-A models have better computational stability and convergence.This paper obtains the influence of different turbulence models on the accuracy of the calculated results of the flow field of turbomachinery by the comparison and analysis of the calculated results of examples,and it can provide reference for the selection and improvement of turbulence models in numerical analysis of flow field of turbomachinery.