某轻卡导流罩CFD分析及设计优化

Numerical simulation of flow field around a light truck analysis and design optimization

以某型国产厢式轻型卡车为研究对象,建立几何模型、有限元模型,利用CFD软件对原模型进行数值模拟分析。分析得出的驾驶室与货箱之间高度差区域存在的明显正压区,即为文中空气动力学优化的关键。通过对驾驶室顶部加装导流罩后的模型进行数值模拟,得出导流罩使轻卡的气动阻力大幅减小。采用拉丁超立方试验设计方法继续对导流罩的尺寸位置进行优化,对决定导流罩尺寸的两水平因子设计试验,寻找导流罩的最优尺寸,得到最优导流罩模型的气动阻力系数为0.5486。

In this paper, I put a certain type of domestic light truck as the research object. The next work includes setting up the geometrical model, the establishment of the finite element model and numerical simulation analysis with CFD software STAR-CCM＋. Through my simulation analysis, there is some obvious positive pressure area existing in the height difference between cab and van container. And this obvious positive pressure area is the key part for aerodynamic optimization in this paper. I perform numerical simulations of the model which is equipped with aerodynamic additional devices at the top of the cab. The aerodynamic additional devices include air deflector and well type grilles. The experimental results show that both of the two devices can make light truck aerodynamic drag fell dramatically. The most critical part in this article is optimizing the size of the air deflector＇s position. In order to find the optimal size of the air deflector, I design the experiments about the two parameters determining the size of air deflector according to latin hypercube sampling. After all of this experiments, the optimal result is aerodynamic drag coefficient of 0.5486.Then I make experiments about the size of well type grilles with the algorithm same to the size of air deflector.