【作者】 张奇；

【导师】 赵又群；

【作者基本信息】 南京航空航天大学 ， 车辆工程， 2006， 硕士

【摘要】 在总结国内外文献的基础上,阐述了汽车空气动力学性能研究,以及汽车空气动力学仿真的发展和应用现状,指出了开展汽车空气动力学仿真及其应用研究的重要意义。采用有限差分法,运用FLUENT软件,分析某轿车模型附近的流场,计算出阻力系的数值,研究车身前部改进对汽车外流场的影响。本文主要工作如下:1、根据几何尺寸对典型系统的影响,改变汽车车头外形的基本尺寸,将不同外形尺寸参数下的模型在虚拟流场中进行外流场的数值模拟,分析其对气动性能的影响,得到最基本的外形概念。2、考虑到车头形式的多样性,选择汽车车头的不同布置和相关细节变化。将汽车车头模型在虚拟流场中进行外流场的数值模拟,进一步进行分析研究,得到不同车头形式所具有的各自特点。3、对汽车在60m/s、70m/s和80m/s速度下的外流场情况进行数值模拟和分析,得出高速时的外流场分布特性。4、对三维模型进行外流场的数值模拟,简要分析外流场的分布特点。综合以上工作,明确了汽车车头设计不仅要考虑空气阻力系数的降低,同时要考虑升力系数的变化,以保证良好的行驶性能。在此基础上,提出具有指导意义的车身前部改进方法。更多还原

【Abstract】 The research and development of automobile aerodynamics was introduced based on the published papers, and it can be concluded that Computational Fluid Dynamics (CFD) analysis is an important method in automobile aerodynamics research..Finite Differential Method (FDM) was applied to analyze the external flow field by FLUENT and calculate the drag coefficient, and the result of the external flow field by changing the shape of automobile model can be compared. The main works of this paper are:1. Typical systematic effects due to geometry change are well known. The external flow field of the automobile model was simulated to find out how it reacted to the aerodynamics characteristic, when the foreside geometry of automobile body changed. The basic model shape could also be obtained.2. Considering multiplicity of automobile model style, more research about the external flow field of the automobile model by choosing different collocation and changing the detail about the foreside of automobile body was carried out. The result is that the different style can satisfy different request.3. The external flow field of the automobile model was simulated at speed 60m/s, 70m/s and 80m/s. The conclusion is that the characteristic about the external flow field of the automobile model distributes similarly.4. The external flow field of the 3D model was simulated and the characteristic about it was described simply.In conclusion, the design of automobile model is not only to reduce drag coefficient but also to improve lift coefficient, so the automobile has good performance. The conclusions in this paper can direct the foreside design of automobile body.更多还原