Achieving fast and efficient combustion is considered as the primary difficulty in overcoming the high-Mach-number scramjet. A novel injection strategy with coflows has been proposed to improve the combustion efficiency, however, the inherent dynamics that drives the partially-premixed combustion is still not very clear. Numerical simulation is adopted to investigate the supersonic partially-premixed flame formed by the coflows of inner jet and annular vitiated air. Validation of numerical results has been conducted by comparing with the experimental data, and the predicted values show a reasonably good agreement with that in the experiments. Numerical results indicate that the supersonic jet flame is stabilized with a certain of lift-off height, with the dynamics balance of flow transport and flame propagation in the autoignition-dominated flame base. According to the flame index, the supersonic reactive flow fields are divided into three stages, including the no reaction region, premixed flame region and diffusion flame region. On this basis, the influence of equivalence ratio and injecting velocity of inner jet on the lift-off behaviors of jet flame, is explored by a series of contrastive analysis.

实现快速高效燃烧被认为是攻克高马赫数超燃冲压发动机的首要难点。已经提出了一种带有协流的新型喷射策略来提高燃烧效率，但是，驱动部分预混燃烧的内在动力学仍然不是很清楚。采用数值模拟研究了内射流与环形污染空气并流形成的超音速部分预混火焰。通过与实验数据的比较对数值结果进行了验证，预测值与实验值吻合较好。数值结果表明，超音速射流火焰在一定的升空高度下是稳定的，具有自燃主导的火焰基中流动传输和火焰传播的动力学平衡。根据火焰指数，超声速反应流场分为三个阶段，包括无反应区、预混火焰区和扩散火焰区。在此基础上，通过一系列对比分析，探讨了内射流当量比和喷射速度对射流火焰升空行为的影响。