Influences of Different Front and Rear Wheel Designs on Aerodynamic Drag of a Sedan Type Passenger Car
Influences of Different Front and Rear Wheel Designs on Aerodynamic Drag of a Sedan Type Passenger Car
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不同前后轮设计对轿车型客车气动阻力的影响
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
L. Löfdahl
中科院分区：
文献类型：
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作者：
Christoffer Landström;T. Walker;L. Christoffersen;L. Löfdahl
开发更节能的乘用车已经成为汽车工业面临的最大挑战之一。这涉及到许多不同的工程领域，并且每个完成的模型总是在不同的需求之间做出妥协。乘用车空气动力学也不例外；外观的形状通常由造型决定，发动机舱区域由包装问题等等。车轮设计也是不同要求之间的妥协，如空气动力阻力和制动冷却，但由于车轮和轮壳负责高达四分之一的整体空气动力阻力在现代乘用车，这并不奇怪，努力提高车轮空气动力学。车轮上的实际作用力通常不是总阻力的四分之一，但由于车轮与其他几个关键气流特征（如冷却气流、车身底部气流和基底尾迹）的强烈相互作用，车轮对车辆的整体空气动力学性能有很大影响。
Efforts towards ever more energy efficient passenger cars have become one of the largest challenges of the automotive industry. This involves numerous different fields of engineering, and every finished model is always a compromise between different requirements. Passenger car aerodynamics is no exception; the shape of the exterior is often dictated by styling, engine bay region by packaging issues etcetera. Wheel design is also a compromise between different requirements such as aerodynamic drag and brake cooling, but as the wheels and wheel housings are responsible for up to a quarter of the overall aerodynamic drag on a modern passenger car, it is not surprising that efforts are put towards improving the wheel aerodynamics. The actual force on the wheels is typically not a full quarter of the overall drag, but as the wheels strongly interact with several other key flow features such as cooling air flow, underbody flow and the base wake, the wheels have a large influence on the overall aerodynamic performance of the vehicle.
This study investigates the potential of different wheel design parameters focusing on reduced aerodynamic drag. A correlation with experimental measurements on a full size vehicle is presented and several additional configurations are analyzed numerically using a standard automotive CFD approach. Furthermore, the potential of optimizing the front and rear wheels individually is investigated to some extend.
Results show that closing most of the rear wheels results in local drag reductions along the rear end underbody, rear wheels and vehicle base. The fully covered rear wheel typically reduced base drag between 6-7 drag counts. Effects of covering the front wheels were more complex as both upstream and downstream flow regions were affected, and it was shown that for the vehicle investigated in this study a limited amount of outer radial covering of the wheel gave the largest drag reduction. The investigation of using different front and rear wheel designs showed that this concept have potential in reducing overall drag as it generated the largest drag reduction in this study of approximately 22 drag counts.