Research On Unsteady Fluid Solid Coupling Numerical Simulation Method Of H-type Vertical Axis Wind Turbine

Because of simple structure and not been concerned about the wind direction,the vertical-axis wind turbine has attracted many researchers to study it.Wind turbines are becoming more and more large-scale.This is a huge challenge for the structural strength of the wind rotor that the mass of the wind rotor and the aerodynamic load of wind rotor also increase as the size of the wind turbine increases.Moreover,unsteady flow characteristics such as wind shear of vertical axis wind turbine blades are more significant than horizontal axis wind turbine blades.The traditional empirical model of blade aerodynamic load will lead to large errors.In order to ensure the safe and stable operation of a 6MW H-type vertical axis wind turbine,the numerical simulation method of aerodynamic load in turbulent wind field and the structural form and strength characteristics of H-type wind turbine are studied in this research.Firstly,the main operation principle of H-type vertical axis wind turbine is revealed based on the characteristics of blade airfoil structure and its aerodynamic parameters and Blade Element-Momentum Theory.The thesis details the definition of aerodynamic parameters of the wind turbine.The theoretical basis of computational fluid dynamics and fluid-structure coupling analysis is introduced in detail.This article explains the operation principle of the sliding mesh technology used in numerical simulation.And the evaluation criteria for numerical simulation convergence are determined.The above theoretical basis guides the research and analysis of this article.Taking H-type vertical axis wind turbine in a R & D and manufacturing stage as the research object,2D and 3D flow field models of the wind rotor and its structural model are established by PROFILI software and SOLIDWORKS software based on similarity criterion.The finite element model of wind rotor structure is established by ANSYS software.The flow field model is meshed with ICEM software,and the mesh independence is verified.For the NACA 0018 airfoil used in the H-type wind turbine blade,the lift coefficient is calculated by different turbulence models of FLUENT software.Comparing the calculation results,the similarities between the simulated values of software and the experimental values of the wind tunnel are as follows: RNG k-? model< Realizable k-? model< SST k-? model.According to the calculation results,a turbulence model suitable for fluid-structure coupling analysis is determined.The aerodynamic performance of the H-type vertical axis wind turbine was explored through a two-dimensional wind turbine flow field model,and it was found that the wind turbine had the largest starting moment when it was at an azimuth of 20 °,and the wind turbine was most easily started at this azimuth angle.The numerical simulation of the operation process of a wind turbine shows that as the tip speed ratio of the wind turbine increases,its rotor power coefficient gradually increases to the maximum value and then decreases gradually.Finally,according to the boundary conditions of each working condition obtained by simulation analysis,using the constructed 3D flow field mesh model and the structural finite element model of the wind turbine,unidirectional fluid-structure coupling structural strength check of wind turbine are carried out under three working conditions.These three working conditions are the starting condition,rated condition,and limiting condition.The research work has important engineering application value for the R & D,manufacturing and safe and stable operation of this type of vertical axis wind turbine.