The Research Of Body Pneumatic Feature And Modeling Optimization For An Electric Vehicle

The aerodynamic feature of car makes an important impact on the pneumatic feature of the complete vehicle, and directly affects the power performance, economic performance and control stability performance. It is an important problem of automobile's research and development facing that how to reduce the pneumatic resistance of vehicle body, improve the running stability of the automobile performance, safety performance and lower the fuel consumption rate. The multi-energy vehicle is the object of text, which analyses pneumatic feature of the multi-energy vehicle's body.The aerodynamic resistance is in direct proportion to the square of vehicle speed, thus the fuel and power consumed by aerodynamic resistance is in direct proportion to the square of vehicle speed. In today's energy crisis, saving energy is the most important thing. To reduce the aerodynamic resistance coefficient is one of the effective way to save energy. Also, with the reducing of the coefficient, the running stability and crosswind stability were improved at the same time. Through the changing of some parameters, the variety discipline was found using orthogonal experiment, seeking for a better body aerodynamic parameter based on the experiment result.Currently, most of the thesis about the optimization of vehicle body aerodynamic parameters just did the research on the influencing factors separately, with the factors interaction ignored. But it is impossible to do an all-around experiment because of the limited time and sources. Using the orthogonal experiment method, in this thesis, 6 main parameters of the vehicle body was selected to do the optimizing analyses.This thesis introduces the method and characteristics of the numerical simulation and theory turbulence models, meanwhile, analyses pneumatic feature which is based on RNG/k-εturbulence model's theory. The thesis applies strategy of gradient self-adaptive T/Grid mesh, analyses the feature of mesh independence. and the external flow field of this vehicle type's body.According to the demand of structure and dimension of the vehicle body, the text chooses the parameter affecting pneumatic resistance coefficient of the vehicle body to optimize. The text confirms the six parameter, such as, angle of rear fan, the angle of tail upwarp,and so on. The text applies the method of orthogonal experiment to test parameter of vehicle body so as to find out the best parameter and get change trends of every pneumatic resistance coefficient following every optimization parameter, which is based on the result of the orthogonal experiment.The thesis verifies correctness of vehicle body's model after being optimized by analyzing pneumatic feature and comparing it with the important parameters, for instance, vehicle body's external flow field of original vehicle type, pneumatic resistance coefficient, etc, which according to the model of vehicle body after the best parameter builds optimization.