为了通过优化风洞抽吸系统参数来改善抽吸效果从而提高汽车模型风洞流场品质,利用风洞试验数据与计算流体动力学仿真方法建立抽吸系统的Kriging近似模型,采用非支配排序遗传算法对抽吸系统参数进行多目标优化,对比分析参数优化前后抽吸系统对MIRA阶梯背模型风洞试验结果所造成的影响,从风洞附面层厚度、模型尾流结构、模型外部压力的变化3个方面探讨了抽吸参数差异引起流场变化的物理机制.结果表明:参数优化后风洞抽吸系统的抽吸效果得到增强,地面附面层厚度减小导致模型底部气流速度增大,尾部负压区增大导致阻力增大,底部前端负压区增大和行李舱盖上方正压区增大导致升力减小.
Abstract
In order to improve the quality of flow field in automotive model wind tunnel through optimizing the parameters of suction system, the wind tunnel experiment data and computational fluid dynamics (CFD) simulation method were used to establish Kriging approximation model of suction system and nondominated sorting genetic algorithm was used in the multi-objective optimization of suction system parameters. Effects of suction system on wind tunnel test results of motor industry research association (MIRA) ladder back model, with and without parameters optimization, were compared and analyzed. The physical mechanism of the flow field variation due to different suction parameters was investigated in terms of the variation of the thickness of the ground boundary layer, the automotive tail flow and the external pressure. The results show that the suction effect is enhanced after parameters optimization. The decrease of the thickness of the ground boundary layer leads to the increase of the flow velocity at the rear of automotive. The increase of rear negative pressure area contributes to the increase of the drag force. The increase of negative pressure area at the front of automotive bottom and increase of positive pressure area above the trunk lid lead to the decrease of lift force.
关键词
汽车工程 /
抽吸系统 /
风洞试验 /
参数优化 /
边界层 /
抽吸率 /
仿真
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Key words
automotive engineering /
suction system /
wind tunnel test /
parameter optimization /
boundary layer /
suction rate /
simulation
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中图分类号：
U467.13
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脚注
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基金
国家自然科学基金项目(51375155);湖南省自然科学基金项目(12JJ3041)
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