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前缘钝化尺度是高超声速进气道设计中的关键参数。针对一种前体锥加弯曲压缩面的高超声速轴对称进气道,选取最大尺度为3.2mm(5%唇缘半径)的几种典型鼻锥钝化半径,在马赫数Ma=6来流,及模型安装攻角为0°、4°、7°的条件下开展鼻锥钝化尺度对进气道流动性能影响的实验研究。采用纹影拍摄及压力测量记录各来流条件下进气道前体流场结构及壁面压强分布,并在无攻角来流条件下利用微型扰流器进行边界层强制转捩研究。结果表明,对无攻角来流而言,即使是尺度高达3.2mm的钝化半径对进气道前体流场结构及壁面静压分布也基本没有影响。此来流条件下,几种不同鼻锥钝化半径的前体压缩面均出现小范围流动分离,而添加扰流器后该分离区均消失。钝化尺度的影响随着攻角的增加而显现,尽管不同鼻锥钝化尺度下迎风面流场及壁面压强分布几乎没有差别,但背风面随钝化尺度增大表现为边界层明显增厚、流动趋于不稳定。其中最大钝化尺度R=3.2mm的构型在4°攻角来流时背风面即出现明显的分离区,而7°攻角来流时背风面更是出现大范围流动分离、进气道背风侧不起动,并导致进气道内部壁面压强显著下降。
Leading-edge passivation dimensions are key parameters in hypersonic inlet design. For a hypersonic axisymmetric inlet with a precursor cone and a curved compression surface, several typical diameters of the nasal tip passivation radius of 3.2 mm (5% lip radius) were selected at the maximum scale of Mach = 6 , And experimentally studied the influence of the size of the nose cone passivation on the inlet flow performance under the conditions of 0 °, 4 ° and 7 ° angle of attack. The flow field structure and the wall pressure distribution of the inlet fluid were recorded by using Wen shot and pressure measurement. The micro-spoiler was used to study the forced transition of the boundary layer under the condition of no angle of attack. The results show that for the non-angle of attack flow, even the passivation radius of up to 3.2mm does not affect the flow field structure and wall static pressure distribution of inlet precursors. Under this condition of flow, the compression surfaces of several precursors with different detonation radius of nose cone appeared small-scale flow separation, but the separation zone disappeared after adding spoiler. The influence of the passivation scale appears with the increase of the angle of attack. Although there is almost no difference between the pressure distribution on the windward surface and the wall under different passivities, the leeward surface increases obviously with the increase of passivation scale , The flow tends to be unstable. The configuration with the largest passivation scale R = 3.2mm showed a clear separation zone at 4 ° angle of attack, while a large range of flow separation occurred at the angle of 7 °, The leeward side does not start and leads to a significant drop in the pressure inside the intake duct wall.