Analysis And Optimization Of Aerodynamic Performance Of Small Electric Car Body Based On FLUENT

With the implementation of national energy conservation and emission reduction policies,electric vehicles have become the future trend to replace fuel vehicles.However,the endurance problem of electric vehicles has always been a bottleneck,especially for those drivers who have the need to drive long distances.Such an endurance disadvantage hinders the widespread acceptance of electric vehicles in the market.To solve the range problem,in addition to battery technology,on the other hand is to improve the aerodynamic performance of the car,reduce wind resistance,improve driving stability.This is of great significance to improve the competitiveness of enterprises,enhance the market share of electric vehicles and reduce environmental pressure.In this paper,a domestic pure electric vehicle is taken as the research object.Based on three-dimensional,steady and incompressible equations,the large fluid dynamics software FLUENT is used to analyze the external field and aerodynamic performance of the vehicle body,and the local modeling of its aerodynamic performance is optimized.Firstly,this paper analyzes the design style and language of small electric cars at home and abroad,finds out several key factors that affect the body shape and explains how they affect the body shape design.Finally,it summarizes the design ideas and main trends of small electric cars in the future and establishes a three-dimensional mechanical model for a small electric car on the market.The flow field,flow spectrum,aerodynamic force and aerodynamic torque of vehicle body under ambient wind speed are numerically simulated.Five kinds of crosswind conditions with positive wind conditions and yaw angles of 6°、12°、18°、24° and 30° were numerally simulated,and the aerodynamic and aerodynamic coefficients were analyzed under the five wind angles.The control variable method is used to study several parameters of the model that have a great influence on aerodynamic parameters,which are tail,head chamfer radius and ground clearance.The research results show that reducing ground clearance and appropriately changing the Angle and installation position of the tail can reduce the wind resistance of the body,while the head chamfer radius has little influence on reducing wind resistance.According to the simulation results of a single factor,the orthogonal experiment of 16 models with five factors and four levels was carried out.Finally,the optimal combination was selected from the results to form the improved body model,and the numerical analysis was carried out again to verify the accuracy of the experiment.Finally,compare the operating conditions with the original model separately,and its performance was evaluated through the velocity distribution diagram,pressure distribution diagram and turbulent kinetic energy distribution diagram.Experimental verification was carried out.According to the 1:25 scale of the car body model,the physical model was made by 3D printing.The low-speed wind tunnel laboratory of YANGZHOU University was used as the experimental site,and the aerodynamic characteristics of the car body were tested with a DC suction teaching wind tunnel.The accuracy of the simulation results of the aerodynamic characteristics of the car body in this paper was verified,which has certain reference value for the further development of the aerodynamic research of electric vehicles.