Research On Outflow Field Simulation And Body-Diversion Optimization Of A Passenger Car Based On CFD

Relevant theoretical research and experimental data show that the aerodynamics of a car is very important.Each time the air resistance is reduced by 10%,the fuel consumption can be reduced by 5%.This effect is especially noticeable when the car is traveling at a high speed.This paper introduces the basic principle of fluid mechanics and basic control equations,the description of fluid motion,the establishment of Navier-Stokes equations and the theories and analytical methods commonly used in fluid mechanics.The relationship between computational fluid dynamics(CFD)and vehicle aerodynamics The simulation lays the theoretical foundation to illustrate the commonly used aerodynamic package to provide reference for the optimization of the flow field.Wind tunnel testing is an essential facility for the development of automotive aerodynamics.Only the combination of test and simulation,in order to achieve the ultimate purpose of mass production.The basic situation of experimental wind tunnel used in automotive aerodynamics is discussed,and some basic methods of wind tunnel experiment are introduced.The main software used and the characteristics of the wind tunnel are introduced to pave the way for further simulation.In the process of simulation,the selection of outer body model and geometry cleaning into a single connected area were conducted.The partition and the physical boundary conditions of the model were imported into CCM + software.After simulation,the coefficient drag of outer body flow field was 0.3043.The setting method adopted is based on the setting method of the bench marking model of the simulation test of China Automotive Technology Research Center.The error of the test results is within the allowable range and the trend is consistent.The method of simulation is proved to be reliable and effective to set the subject,You can carry out simulation of body flow field optimization.After a series of optimization studies of diversion optimization,the original drag coefficient is reduced from 0.3043 to 0.2513,which achieves the purpose of drag reduction optimization.It proves that the scheme is feasible and effective and has reference value for engineering problems.Focusing on the influencing factors of wind resistance optimization,the influence of the rear view mirror,tail modeling and other sensitive parts,and the exploration of the pit optimization method,the theoretical basis and simulation optimization method for the aerodynamic research and development of passenger cars are provided.