Numerical Simulation Of Wind Turbine Wakes Based On Reynolds-averaged Navier-stokes Method

The power generation efficiency of the wind field is seriously restricted under the wind turbine wakes effect.The application of CFD(Computational Fluid Dynamics)method to the study of wind turbine wakes model is a prospective topic in wind power engineering at present.In this paper,the velocity field and turbulence field information of wind turbine wakes are simulated by RANS(Reynolds Average)numerical method.In the aspect of wakes modeling,a wind turbine wakes model based on RANS method is developed.Firstly,the global governing equations of the RANS method are established.Then a modified BEM-Fuzzy model of wind turbine is established by BEM(Blade Element Momentum Aerodynamic)theory and Fuzzy distribution method,meanwhile three corrections including blade tip loss,hub loss and attack angle deviation are considered,which is added to the whole equations as the volume force source term.Finally,the SST k-? turbulence equation is established by adding the source term,changing the parameters and reducing the dissipation term,and the overall modeling of the wind turbine wakes model is completed.In the aspect of solving the model equations,the SIMPLE(Semi-Implicit Method for Pressure Linked Equations)algorithm based on the Fluent 6.0 solver platform is used to solve the wind turbine wakes equations.A variable size mesh of regular hexahedron is designed,effectively reducing the number of grids.The adaptive relaxation factor method is used to effectively reduce the iterative convergence step.The convergence time step is effectively reduced by Fluent parallel technology.In the design of experimental results,the two different boundary conditions of uniform inflow and wind shear inflow are considered.The correct and effective calculation results of velocity field and turbulence field are obtained by comparing with the measured data of a wind farms in Denmark and a wind turbine of micro size.The effect of the modified wind turbine model and turbulence model on the velocity field and turbulence field of the near and far wakes region is verified.Finally,the calculation speed of the wake model is evaluated.