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连续旋转爆轰发动机(CRDE)中燃料和氧化剂的快速掺混是实现爆轰波成功起爆和稳定传播的重要前提,然而目前国际上关于这方面的研究还相对较少。本文采用大涡模拟(LES)方法,对非预混CRDE中燃料和氧化剂的混合过程及其主要机理开展深入研究。研究结果表明,非预混CRDE流场中存在欠膨胀特征、大尺度涡结构,以及回流区等复杂的流动现象,其中由于Kelvin-Helmholtz(K-H)不稳定性产生的大尺度湍流涡结构是促进氢/氧混合的主要机制。此外,本文还考察了氧气喷注位置对非预混CRDE的流场结构和混合特征的影响,发现氧气喷注位置会影响射流剪切层形态、涡尺度,以及回流区分布等,进而影响氢气和氧气射流的混合过程和混合程度。与其他进气位置相比,氧气在靠近内壁面喷注时更有利于氢/氧的快速掺混。
Rapid mixing of fuel and oxidant in continuous rotary detonation engine (CRDE) is an important prerequisite for the successful initiation and stable propagation of detonation waves. However, there are relatively few studies in this field at present. In this paper, large eddy simulation (LES) method is used to investigate the mixing process of fuel and oxidant and its main mechanism in non-premixed CRDE. The results show that there are complex flow phenomena such as under-expansion, large-scale vortex structures and recirculation zone in the non-premixed CRDE flow field. The large-scale turbulent eddy structure due to the instability of Kelvin-Helmholtz (KH) The main mechanism of hydrogen / oxygen mixing. In addition, the effect of oxygen injection position on the flow field structure and mixing characteristics of non-premixed CRDE was also investigated. It was found that the position of oxygen injection affected the shape of shear layer, the vortex scale and the distribution of reflux zone, And oxygen jet mixing process and the degree of mixing. Compared with other intake position, oxygen injection near the inner wall is more conducive to hydrogen / oxygen rapid mixing.