Study On The Multi-stage Compressor By Using Three-dimensional Numerical

With the rapid development of computational fluid dynamics and optimization algorithm,the optimization techniques of turbomachinery have been developed speedy. But the numerical simulation of the multi-stage compressor is still a challenge area. To obtain a fast and exact method of the numerical simulation for engineering is necessary.To meet the requirements for 3D viscous flow computational software in compressor design, base on computed the internal flow and the overall performance of the turbo-charging set compressor,a fast full 3D viscous numerical method for the computation of overall aerodynamic performance in multi-stages axial-flow compressor was introduced.For the inlet part of the compressor, a finite volume method solving three-dimensional Reynolds-averaged Navier-Stokes viscous partial differential equations is employed to study the internal flow field of whole system, which including meridian acceleration rotor, vaneless diffuser and volute, by using the commercial CFD code FLUENT. The hybrid structure/unstructured grid is adopted to mesh the complex computational domain. Standard two-equation k ?εturbulent model with standard wall functions is used to evaluate the turbulent diffusivity. The pressure-velocity coupling is solved using SIMPLE algorithm.For the blade part of the compressor, eruanus solver of Numeca Fine/Turbo software is used in the numerical calculation of this article. 3D Reynolds-averaging Navier-Stokes equation is solved with the Jameson finite volume scheme and Spalart-Allmaras turbulence model. In relative coordinates system, using explicit Runge-Kutta integration in time to get steady solution. Residual smoothing,local time stepping and a new multi-grid scheme were employed to improve calculative efficiency and accelerate the convergence. The calculation work also researched the influence of the tip clearance of rotor blades and the Laminar-Turbulent transition.After adding the transition,it can simulate the flow on the surface of the leaf more better,and from the computational results to see:for this situation which the Reynolds is large,the transition is not high-impacted;from the computational time to see;it will not increase the difficulty of calculation,but it still needs to continue to calculate the transition after the convergent results,in order to extend the working time.