一种新型车用导流器的研究及其气动性能优化

Study on a Novel Vehicle Spoiler and Its Aerodynamic Optimization

针对传统导流器仅能单一地减小阻力或升力的问题,基于某直背车型设计一款能同时减小阻力和升力的新型导流器。首先,基于其需满足的流场条件确定导流器横截面初始的上下型线,并使用准均匀B样条进行拟合,再沿y方向拉伸出导流器的型面。接着,通过改变截面型线控制点,得到一系列不同的型面,运用遗传算法寻优找到导流器最优型面。最后,为进一步减小阻力和升力,基于导流器最优截面,改变导流器的宽度和安装位置与角度,并采用实验设计、近似模型和NSGA-II遗传算法进一步优化。模型风洞实验验证的结果表明:整车阻力减小3.8%,升力减小7.9%。

In view of that traditional spoiler can only reduce aerodynamic drag or lift force,a novel spoiler,which can reduce both drag and lift force,is designed based on a square-back vehicle.Firstly,according to the flow field condition the spoiler should meet,the initial upper and bottom curves of the cross-section of spoiler are determined and fitted by quasi-uniform B-spline curve,and are drawn along y direction to form the surface of spoiler.Then a series of surfaces are obtained by changing the control points of section curves,among which an optimum surface is obtained by using genetic algorithm.Finally,for further reducing the drag and lift force,a further optimization is conducted by adopting the design of experiment,approximate model and NSGA-II genetic algorithm and changing the width and the installation position and angle of spoiler based on optimum surface of spoiler.The results of verification experiment on model wind-tunnel show that with the spoiler optimized the drag and lift force of vehicle reduce by 3.8% and 7.9% respectively.