基于近似模型的气动升力优化研究

Research on Optimization of Aerodynamic Lift Performance Based on an Approximate Model

为改善汽车高速行驶时气动升力引起的气动稳定性变差问题,提出了封闭汽车前轴底部和增加“前齿”附加装置的改进设计方法,以实现某款轿车优良的气动升力特性。即在风洞实验验证算法精度的基础上,采用优化拉丁超立方方法进行了样本点设计和采样,利用Kriging代理模型构建了优化设计变量和气动升力系数之间的近似模型,以前轴升力愈负为优化目标,采用多岛遗传算法,对汽车前齿附加装置进行了参数寻优。结果表明:应用LBM求解汽车气动升力,具有较高的计算精度;将轿车前轴附近的底部封闭,可有效改善气动升力特性,使气动升力约降低36.4%;增加宽度和高度分别为359.54 mm和27.46 mm的前齿后,汽车的前轴升力系数Clf为-0.0637,满足实际工程要求。

In view of an improvement of the aerodynamic stability caused by aerodynamic lift at a high speed,an improved design method has been proposed of closing the bottom of front axle with an addition of the“front teeth”attachment device so as to achieve an excellent vehicle aerodynamic lift performance.Based on the accuracy of the algorithm verified by wind tunnel experiments,the optimal Latin hypercube method is used to design the sample points,with the Kriging proxy model adopted to construct the approximate model between the optimal design variables and the aerodynamic lift coefficient.Meanwhile,the multi-island Genetic Algorithm(Mga)is used for an optimization of the parameters of the automobile front tooth attachment.The results show that it is characterized with a high accuracy with the application of LBM to the calculation of vehicle aerodynamic lift;by closing the bottom near the front axle,the aerodynamic lift characteristics can be effectively improved,with the aerodynamic lift reduced by 36.4%;with a respective addition of 359.54 mm width and 27.46 mm of the height front teeth,the front axle lift coefficient Clf is maintained at-0.0637,which meets the actual engineering requirements.