Optimization Design Of Geometric Parameters For A SUV Body Local On External Flow Field

Nowadays,with the increasing energy shortage and stricter regulations for energy saving and emission reduction in the world,the optimization of automobile body modeling is conducive to improving the fuel economy and power performance of automobiles.Therefore,it has great practical significance to study how to reduce the drag coefficient of automobiles.With enhancing of independent research and development ability of domestic automobile,all enterprises have proposed to effectively control the resistance coefficient of the automobile in the initial stage of modelling.The traditional design and development process is time-consuming and labor-intensive,can no longer meet the requirements of modern car companies.Body modelling is closely related to aerodynamics.With the rapid development of computer technology and numerical simulation,computational fluid dynamics is more and more used in automobile aerodynamics to achieve energy saving and reduce consumption,while shortening the period of body modelling design.This paper optimizes the local geometric parameters of a battery electric SUV,rationally simplifies the structure of body to establishe a finite element model and simulation domain.Setting initial conditions to carry out the finite element analysis of the external flow field of body.Six structural features which have a great influence on the aerodynamic characteristics of automobiles are selected to reduce the drag coefficient,single factor simulation analysis of the six features is carried out to study the effects of six features on the external flow field of automobiles under different geometric parameters.Considering the influence between the six features,orthogonal experiments are carried out to optimize the six features.Using L25(56)orthogonal table,from the perspective of multi-factors,aiming at reducing the drag coefficient and optimize the external flow field of the automobile,the saliency of six characteristic factors is obtained.According to the significant difference of each factor,take the corresponding best index value and get the best body geometry parameters.Through the optimization of the body after local optimization,the optimized design of this paper can improve the external flow field characteristics of the SUV and reduce the drag coefficient.The optimization of automobile body modelling is conducive to improving the fuel economy and power performance of automobiles.Applying orthogonal test to the process of automobile modelling design can optimize the modelling more comprehensively and accurately,which is of great significance for the development and optimization of new automobile products.