【作者】 邓远灏；

【导师】 乐嘉陵；

【作者基本信息】 西北工业大学 ， 航空宇航推进理论与工程， 2005， 硕士

【摘要】 隔离段是超燃冲压发动机的一个重要部件,它位于进气道和燃烧室之间,有两个重要的作用:一是隔离进气道和燃烧室间的相互干扰,以便提供给进气道一个较宽的稳定工作范围;另一个是使超燃冲压发动机能以双模态方式工作。由于隔离段内气体流动的复杂性及其广泛的工程应用前景,隔离段内的流动特性引起了人们的关注。 本文针对隔离段内的流动特性,利用商业CFD软件FLUENT对其内部流场进行二维与三维数值模拟,希望通过本文的研究可以了解隔离段内的流动特性,并为隔离段的设计打下基础。首先综合国内外的相关研究成果,详细分析了隔离段内部流场,并提出了隔离段的一种长高比估算方法。其次针对两个有名的隔离段实验研究,本文借助FLUENT软件对隔离段进行了算例验证,并将计算结果与实验数据作了对比,研究了不同的湍流模型、不同的网格、不同的数值计算格式和不同的几何模型对求解的影响,并提出了一种适用于隔离段流场计算的数值方法。最后通过数值模拟研究了出口反压、来流马赫数、附面层厚度、来流雷诺数、长高比、扩张角、缩比和宽高比对隔离段内部流场的影响,获得了大量的计算结果,较为详细地给出隔离段内部流场随不同流动参数和几何参数而变化的规律。更多还原

【Abstract】 The isolator which is placed between the inlet and the combustor is a key component of the scramjet engine. The isolator includes two important functions: One is to provide a wide work scope to inlet, Another is to make scramjet engine work within the dual-mode. The phenomenon of supersonic flow in isolator has been of great interest for decades due to both the complexity in aerodynamics and its wide engineering application.An investigation of flow characteristics in the isolator was studied in the thesis. The commercial CFD software FLUENT was used to carry on the 2D and 3D numerical simulations of the internal flow field of isolator. The investigation of flow characteristics in the isolator contributes to further understanding the flow field and the design of the isolator. According to the related research, the internal flow field in isolator was analyzed in detail and a design method of the isolator was presented. Experiments conducted by Billig and Carroll were used as the test case. Aspects relating to turbulence model, mesh, numerical scheme and geometric model were studied. Comparisons are made of wall pressure distribution, centerline pressure distribution and Mach number contours. Results obtained in the present study show very good agreement with the experimental data. The flow field properties of various flow parameters and geometric parameters of isolator were computationally evaluated in the thesis. The effects of the parameters including back pressure, Mach number, boundary layer thickness, Reynolds number, L/H, divergence angle, scaling and aspect ratio were discussed.更多还原