乘用车特征参数风阻灵敏度耦合分析

Drag Coefficient Sensitivity Coupling Analysis of the Characteristic Parameters of the Passenger Vehicle

乘用车油耗高低对能源有着极为重要的影响,而减小整车风阻系数,能够在一定程度上降低能源消耗。一般降低风阻系数的方案是简单的对某一或某几个参数进行单一分析,直接对参数进行试验分析,很少有将特征参数结合起来进行耦合试验分析。以MIRA快背式车型为研究对象,选择计算流体动力学分析方法,首先通过整车外流场分析获得了发动机罩夹角、前风窗夹角和离去角等3个特征参数;然后进行单因素分析研究,获得了各单因素的风阻灵敏度,并验证该3个特征参数的重要性;最后将3因素组合分析,得到模型在各单因素下最优风阻系数,获得各参数在最低风阻系数下的最佳组合,使整车风阻系数下降了9.06%。

The fuel consumption of passenger vehicles has a vital impact on energy. The energy consumption can be constrained by reducing the drag coefficient of the vehicle. Generally,conventional methods of reducing the drag coefficient are simply based on analysis of few experimental parameters without combining the characteristic parameters through coupling tests. In this work,MIRA fast-back model has been chosen as the target. The flow field of the vehicle was firstly built up using computational fluid dynamics analysis to obtain the three characteristic parameters,in terms of hood angle,the angle of the front wind window,and the angle of departure. Sensitivity and importance of the parameters was then investigated by conducting single factor analysis. Finally,the optimal combination of the three parameters under the minimum drag coefficient can be obtained through the three-factor orthogonal experimental analysis. As result,the drag coefficient calculated from this work decreases 9. 06%when comparing with the original model.