斜爆轰发动机作为新一代高超声速吸气式发动机具有广阔的应用前景。然而爆轰燃烧属于预混燃烧的特点使斜爆轰发动机面临特殊的燃料混合问题。燃料在斜爆轰发动机进气道内喷注使燃料需要与高超声速来流充分混合且保证不发生提前燃烧。因此，相较于超燃冲压发动机燃烧室内的燃料混合问题，斜爆轰发动机面临的燃料混合问题更加艰巨。本文针对斜爆轰发动机对燃料喷注的要求，通过数值模拟系统地研究了高超声速来流下单孔射流和串列射流的流场特性以及射流之间的相互作用，并取得了以下主要研究成果：

首先，通过来流马赫8 条件下垂直声速氢气射流的数值模拟，发现了由组成马赫胞的激波结构间的干扰导致的周期振荡现象。利用Liutex 涡识别方法，清晰地显示了射流在高超声速横流作用下形成的涡结构，并详细分析了其产生原理。根据涡结构的形成机理、位置和形态，将所有涡结构划分为五类旋涡系统。

其次，本文进一步分析了不同总压射流与不同马赫来流相互作用所形成的复杂流场结构以及上述参数的影响规律。通过修正自由欠膨胀射流的马赫盘高度预测公式，使其能够预测射流在高超声速来流中的马赫盘高度。同时，发现了温度极值位置在流场中的两种转移模式。通过数据拟合，建立了只需动量通量比的预测流场对称面上弓形激波位置与燃料化学当量比界面位置的预测公式。

最后，由于气动斜坡结构具备侵入式燃料掺混的高混合效率和近壁射流无需考虑结构生存问题的优势，本文对组成气动斜坡的基本构型的串列射流展开了系统研究。主要分析了串列射流出口数、上下级射流强度以及射流孔间间距的影响。同时，对流场中的激波旋涡结构、射流孔间干扰模式、流场高温区以及燃料分布进行了详细分析。在串列多孔射流中，最上游的射流能够阻挡流场中的高温区，并与下游经所有射流出口流出的燃料充分混合。在双孔串列射流的构型中，上游射流能够在下游射流总压不大于上游射流总压的条件下阻挡高温区。此外，通过适当增大双孔串列射流间隙，可以引起上游射流剪切层的大幅波动，并在射流间隙中产生大尺度涡，从而极大地促进上游射流与来流间的混合过程。

The oblique detonation engine (ODE) has broad application prospects as a new generation of hypersonic air-breathing engines. However, the characteristic of detonation combustion as a premixed combustion poses special fuel mixing problems for theODE. Since the fuel is injected into the inlet of the ODE, it needs to be thoroughly mixed with the hypersonic incoming flow and ensure that premature combustion does not occur. Therefore, compared with the fuel mixing problem in the combustion chamber of a scramrjet engine, the fuel mixing problem faced by the ODE is more challenging. Inresponse to the requirements of fuel injection for the ODE, this thesis systematically studied the flow field characteristics and interactions between single jet and tandem jets under hypersonic inflow conditions through numerical simulation, and achieved the following main research results:

The periodic oscillation phenomenon caused by the interaction between shocks that make up the Mach cell was discovered through numerical simulation of a single transverse sonic hydrogen jet under Mach 8 inflow conditions. Using the Liutex vortex identification method, the vortex structures of the jet in hypersonic cross flow were clearly visualized, and the mechanism was analyzed in detail. Based on the mechanism, position, and morphology of the vortex structures, vortex structures were classified into five vortex systems.

This study further analyzes the complex flow field structure formed by the interaction between jets under different total pressure conditions and incoming flows at different Mach numbers, and the influence of the above parameters. By correcting the predictive formula for the height of the Mach disk generated by under-expanded free jet, the formula can predict the height of the Mach disk of the jet in hypersonic flow. Two transfer modes of extreme temperature position in the flow field are found. Through data fitting, predictive formulas were established for predicting the bow shock position and the stoichiometric equivalent ratio interface position on the symmetric plane, which only requires the jet momentum flux ratio.

Finally, due to the advantages of the high mixing efficiency of the intrusive passive fuel mixing structures and the near-wall jet without considering structural survival issues, this thesis conducts a systematic study on the basic configuration of the aerodynamic ramp, focusing on the tandem arranged jets flow. The study mainly analyzes the effects of jet outlet numbers, the strength of upstream and downstream jets, and the spacing between jet orifices. The shock structure, vortex structure, interference mode between jet orifice, high-temperature area, and fuel distribution in the flow field were analyzed separately. In tandem-arranged multi-jets cases, the upstream jet can block the high-temperature region downstream jets and mix with the fuel flowing out from all jet outlets in downstream. In tandem-arranged double-jets cases, the upstream jet can block the high-temperature region for the downstream jet when the total pressure of the downstream jet is not greater than that of the upstream jet. Increasing the spacing between the jets can cause significant oscillation in the upstream shear layer and produce large scale vortices in the gap, which greatly promotes the mixing process between the upstream jet and the incoming flow.