| The car is affected by a variety of air forces that affect the maximum speed,handling stability,and fuel economy of the car when it is running normally in the driveway.Therefore,it is very important to consider the influence of aerodynamics on the performance of the car body in the design and manufacture of the car body,and to study the distribution of the external field of the car body.In this paper,the modified CQ-1 racing car in Changsha Automotive Industry School is taken as the research object.Firstly,the air force acting on the car is analyzed,and the factors that affect the performance of the car and the evaluation method of the performance are studied.Complete racing car modeling design.Then the completed car body modeling is built with CATIA V5R21 software 1:1 scale,and the completed 3D model is imported into the ANSYS ICEM CFD17.0 software for fluid domain definition and mesh division.The meshes are imported into the FLUENT17.0 software to simulate the flow field,and the velocity distribution and pressure distribution of the flow field are obtained.According to the distribution of the car body outflow field and the results of analysis,the shape of the car head is locally optimized,and the corner transition of the car head is increased to make the front part as smooth as possible.Then the modified racing model is imported into the ANSYS ICEM CFD software to mesh,and the flow field distribution of the optimized model is obtained by setting the same boundary conditions in the FLUENT software.It is concluded that the static pressure of the optimized model head is smaller than that of the optimized model.The streamline map fits the body to a higher degree,reducing the resistance coefficient from 0.340 to 0.315.This shows that the optimized model has better streamline distribution and lower drag coefficient,which meets the requirements of aerodynamics.The results show that the optimized model has a better performance of low air resistance.The subjective evaluation and acceleration performance test of the original and the optimized racing model show that the optimized model has better turning stability and driving stability,and the acceleration time is shorter.This helps to increase driverundefineds driving confidence so as to give play to the performance of the car to improve the performance of the race.The decrease of drag coefficient can not only improve the speed of normal driving,but also improve the fuel economy and power characteristics of the car,which has a very positive effect and significance to the design of the car body. |
