关键词: 整车外流场；平整化底盘；空气动力学性能；空气阻力系数

Abstract: The aerodynamic study of automobile chassis is of practical significance for optimizing the aerodynamic performance of the whole vehicle and improving energy efficiency and range. Flattened chassis is constantly appearing in the design of new car models, and the study adopts computational fluid dynamics method to compare and analyze the aerodynamic performance of the whole car through numerical simulation technology. The results show that the flattened chassis design can reduce the wind resistance coefficient of the whole vehicle by about 3.45%, in which the flattened middle floor area of the whole vehicle changes the surface pressure from positive to negative, which enhances the stability of the whole vehicle in high-speed driving. The pressure in the exhaust pipe area in front of the sub-silencer is reduced by 71.5%, effectively reducing airflow separation. The rear floor flattening design can effectively guide the airflow away from the body, reduce the turbulence effect at the rear of the vehicle, and lower the air resistance. The study verifies the effectiveness of the chassis leveling design in improving the aerodynamic performance of the vehicle and provides data support for the aerodynamic optimization of the whole vehicle.

Key words: vehicle external flow field; flattened chassis; aerodynamic performance; aerodynamic drag coefficient