Research On Car’s Aerodynamics Characteristics Influenced By Aero Kit

While a car is moving on the road, air flow around this car will move relative to this car,then producing aerodynamic force and torque. Particularly when the speed was higher, theinfluence of aerodynamic force would be more remarkable. Air resistance and air lift inaerodynamic force significantly affected the automobile. Air resistance would significantlyaffect fuel economy, while air lift would not only reduce the adhesion. Therefore, theresearch on car’s aerodynamic characteristics would be more and more important.This thesis took an automobile model as research object, doing numerical simulation onautomobile external flow-field, analyzing automobile external flow-field with the aero kit,studying the influences on the car’s aerodynamic characteristics with the tool of the CFDsoftware Fluent, And compared the changes of the rear flow field at different speeds,analyzing the changes of aero kit use performance at different speeds. The study can beconcluded that, the rear flow field and the car’s aerodynamic characteristics would beimproved by fixed the aero kit. When the speed is higher, the use of improving car’saerodynamic characteristics is more evident.The main research works of this thesis are:1. The background and the meaning of car’s aerodynamics were introduced, and thetheory basic of the car external flow field was studied.2.3D model of automobile was built by CATIA. In order to mesh this3D model, weimported this model to CAE professional pretreatment software HyperMesh, getting themeshing model. In order to Solve and calculate, imported this meshing model to CFDsoftware Fluent. At the last, Processed and analyzed the Calculated results, getting theConclusion.3. Simulated and analyzed automobile external flow-field, studying car’s aerodynamiccharacteristics, analyzing the speed and pressure distribution of Air flow at eight speeds of36km/h,60km/h,80km/h,108km/h,120km/h,140km/h,160km/h and180km/h.4. Simulated and analyzed the car external flow field, analyzing the changes of car’saerodynamic characteristics at the speed of180km/h, including the changes of flow velocity,pressure distribution and turbulence characteristics around the car. Results show that,installed on the aero kit can improve car’s aerodynamic characteristics.5. Simulated and analyzed the car external flow field, analyzing the changes of the aerokit use performance at eight speeds of36km/h,60km/h,80km/h,108km/h,120km/h,140km/h,160km/h and180km/h. Results show that, when the speed is higher, the use of improving car’s aerodynamic characteristics is more evident.6. Analyzed impact on the car’s aerodynamic characteristics of the size of the aero kit,comparing drag coefficient and lift coefficient by fixed five different sizes of the aero kit.Results show that, the car’s aerodynamic characteristics were the best when the string lengthof the Rear Spoiler is150mm.