超声速气流中斜爆震的反射形成及转捩机制研究

Standing stabilization of an oblique detonation wave (ODW) is very important for an oblique detonation wave engine (ODE) to realize its own performance advantages. In addition, reflection of an ODW is a key factor which significantly influence the standing stabilization. In this project, reflection formation and its transition mechanisms will be investigated through theoretical modelling, numerical and experimental validations, to explore methods of enhancing ODW’s standing stability. The theoretical model for predicting the transition critical angle is aimed to be developed considering chemical non-equilibrium effect behind the ODW. Combined with the ODW initiation criteria, the wave structures in reacting supersonic flows will be analyzed and the model for predicting the Mach stem height of a Mach reflection structure of a shock/ODW will also be developed. Finally, through lateral expansion method of experiment and numerical simulations, the influence of cellular instabilities of ODW on reflection formation and transition will be investigated. This project will be quite instructive to ODW’s application in propulsion systems.

增强斜爆震的驻定稳定性对于实现斜爆震发动机的性能优势至关重要，而斜爆震的壁面反射是影响驻定稳定性的重要因素。本项目拟通过理论建模，数值验证和实验验证的方法研究超声速气流中斜爆震的反射形成及转捩机制，探索增强斜爆震驻定稳定性的方法 。考虑化学非平衡过程，发展适用于预测斜爆震反射转捩临界角度的理论模型；结合斜爆震起爆条件，分析超声速可燃气中的波系特征，建立超声速可燃气中激波/斜爆震马赫反射的马赫干高度预测模型；最后，通过侧向膨胀实验方法及数值模拟，研究胞格不稳定性对斜爆震反射形成及转捩的影响机制。本项目的研究，对于斜爆震燃烧在推进系统中的应用具有重要指导意义。

本项目以高超声速斜爆震冲压发动机为背景，以抑制封闭空间中斜爆震马赫反射，增强斜爆震驻定稳定性为目的，开展了超声速气流中斜爆震的反射形成及转捩机制研究。通过双波/三波理论分析和数值模拟，建立了基于化学非平衡的超声速气流中斜爆震反射流场的物理模型。证明了经典双波/三波理论模型不适用于斜爆震反射流场，需要将ZND模型引入双波/三波理论。经过修正的双波/三波理论模型能够更好得描述斜爆震反射流场。初步建立了斜爆震马赫反射的马赫干高度预测模型。提出并试验验证了通过引入近壁不可燃气体层的方法抑制封闭空间中斜爆震马赫反射的方法，显著增强了斜爆震的驻定稳定性。创新提出了环形/圆截面燃烧室中的螺旋斜爆震燃烧组织方法，通过两个反向对称布置的斜劈在环形/圆截面燃烧室中组织反对称的螺旋斜爆震燃烧，能够避免斜爆震在壁面上的马赫反射，极大增强了斜爆震的驻定稳定性。利用高超声速等效原理结合数值模拟揭示了螺旋斜爆震的传播机制，表明三维定常螺旋斜爆震定性等价于二维弯管中传播的非定常爆震。数值研究了静止气体中的斜爆震反射现象，表明了静止气斜爆震反射现象随着预混气压力、当量比、试验段上下侧高度比等参数的变化规律，揭示了反射过程中胞格不稳定性的演变特性，证明了整个反射过程中反射结构总体上具备自相似性。