克拉玛依职业技术学院毕业论文论文题目学生: 指导教师: 学科、专业: 克拉玛依职业技术学院机械工程系二O 一四年三月摘要随着我国经济的发展,国产厢式汽车越来越得到广泛的使用,厢式汽车行车安全性能也越来越被人们重视。运用计算流体力学的方法,利用大型商业 CFD 计算软件 FLUENT 对国产厢式汽车的外流场进行数值模拟。首先对常见的二方程湍流模型标准 k-e 模型, RNG k-e 模型, SST 湍流模型进行了介绍和比较, 然后应用这三种湍流模型进行 Ahmed 钝体的外流场计算模拟并与风洞实验结果比较,选出最优计算模型。本文选用 SST 湍流模型为厢式汽车外流场的计算模拟的湍流模型。网格质量也是影响计算准确度的重要因素,结构化网格、非结构网格和混合网格具有各自的优缺点,因此根据汽车外流场的实际特性设计了几种网格划分方案,并探讨了它们的优缺点,选出了一个最优网格划分方案。计算分析了在其尾部加装不同形状,不同角度,不同安装位置,不同安装方法的后扰流板对汽车气动特性的影响,通过它们之间数值模拟结果的分析和对比,可以清楚地了解后扰流板在改善汽车的气动特性方面所发挥的独特作用。通过计算分析,探讨了车辆周围气流的流动机理,分析了后扰流板附近负升力的产生原理及汽车后部尾涡对阻力的影响。通过计算模拟安装后扰流板的汽车模型的外流场,提出了合理的后扰流板安装形状及安装位置、角度。后扰流板不仅可以使汽车的气动升力得到降低,还能有效地降低汽车所受阻力,降低汽车油耗,这对提高汽车气动特性有很大的工程指导性。关键词: 后扰流板,湍流模型,空气动力学,操纵稳定性目录摘要······························································ Ⅰ ABSTRACT ·························································· Ⅰ 1引言······························································· 1 研究背景和意义··················································· 1 厢式汽车气动性能的研究现状······································ 2 国外研究发展状况·········································· 2 国内研究发展现状·········································· 3 本文研究的内容··················································· 4 2 后扰流板对汽车气动特性的影响······························· 6 气动阻力·························································· 6 气动升力·························································· 7 后扰流板的作用·········
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