斜爆轰波中胞格结构形成机理的数值研究

Numerical Research on the Formation of Cellular Structures on Oblique Detonation Surfaces

由于激波和燃烧的耦合作用,气相爆轰波波面后方会出现横向运动的激波,从而形成胞格爆轰波结构。对于超声速气流中的斜爆轰波,其胞格结构比正爆轰波更加复杂,研究者对此还缺乏深入的认识。本文采用无粘Euler方程和单步化学反应模型对斜爆轰波进行了数值模拟,重点研究了活化能和诱导斜爆轰波楔面角度对于波面胞格结构的影响。模拟发现,存在2种斜爆轰结构:只存在单向横波和存在双向横波。其中,在双向横波结构后方,首次在斜爆轰结构中发现了波后未反应气团的存在。利用统计方法对斜爆轰中横波的产生过程进行分析,结果表明:2种结构产生过程受到不同因素影响,为斜爆轰波结构预测提供了依据。

Cellular structures on the detonation surfaces derive from the shock and combustion coupling,which generate the transverse waves behind the leading shock. These structures have been studied widely in the normal detonation,but not in the oblique detonation,whose structures are more complicated. Euler equations with one-step chemical reaction model are solved to simulate the oblique detonations,and the effects of activation energy and wedge angle are studied. Numerical results demonstrate that there are two types of cellular structures,one is characterized by one group transverse waves,and the other is characterized by one additional group transverse waves with opposite direction. This study illustrates the formation of post-detonation unreactive pockets in the oblique detonation for the first time. Statistical analysis on the cellular structure is carried out to observe quantitatively the influences of activation energy and wedge angle,which provides the method to predict the structure of oblique detonation.