FSAE赛车二维扩散器气动性能研究

Research on Aerodynamic Performance of 2D Diffuser in Formula SAE Racing Car

基于CFD数值模拟的方法,对方程式赛车空气动力学性能有重要影响的底部扩散器进行二维仿真分析,对比了不同格尼襟翼高度和角度、不同离地间隙下的尾部扩散角度、六种不同维度组合方案下的气动力系数及迹线图,探究其阻力和升力系数的变化规律及匹配原则,确定了相对优化的底部扩散器方案。结果表明:不同离地间隙下随扩散倾角的增加其阻力系数单调递增,在一定范围内离地间隙越低扩散器负升力值越小,在不同区间有不同的变化趋势;扩散倾角长度越长尾部气流易发生分离,易产生气动阻力而影响气动负升力的作用。

The bottom of diffuser which has important effects on the performance of car aerodynamics,was analysed in the two-dimensional simulation based on CFD numerical simulation.Aerodynamic coefficients and trajectories was comparised by Gurney flap height and angle,tail diffusion angle,the tail diffusion angle of different ground clearance,six combinations of different dimensions to explore the change law of drag and lift coefficient and matching principle,and the optimal scheme of bottom diffuser was determined.The results show that the drag coefficient increases monotonically with the increase of diffusion angle under different ground clearance.The lower Ground clearance is,the smaller the value of negative lift diffuser is within limits and there are different trends in different intervals.The longer the diffusion angle is,the easier tail airflow is to be separated,which is easy to produce pneumatic drag and influence the negative lift force.