Numerical simulations were performed to model the non-reacting and reacting flow behind a rearward step flameholder in Mach 1.6 supersonic flow with fuel injection at the step base. The combustor geometry was based on the University of Florida scramjet experimental facility. Turbulence was modeled using k-ω shear stress transport (SST), laminar flamelet was used for combustion modeling. Wall static pressure showed good agreement with experimental data for non-reacting and reacting flow. For non-reacting flow, dummy fuel helium mole fraction distribution in the recirculation region behind the step was validated with planar laser induced fluorescence (PLIF) images in experiments. To improve the combustion characteristics, air was injected in tandem with hydrogen at step base using various configurations. With all fuel injection as baseline, the case with 2 air jets around each fuel jet and air injected at 2 times the stagnation pressure of fuel showed the most improvement compared to other cases. It was most effective in reducing the local fuel richness, shortening the flame length and increasing combustion efficiency.

进行了数值模拟以模拟 1.6 马赫超音速流中向后阶梯火焰稳定器后面的非反应流和反应流，在阶梯底部喷射燃料。燃烧室几何结构基于佛罗里达大学超燃冲压发动机实验设施。湍流使用k-ω建模剪切应力传输 (SST)，层流火焰用于燃烧建模。壁面静压与非反应流和反应流的实验数据显示出良好的一致性。对于非反应流，在实验中使用平面激光诱导荧光 (PLIF) 图像验证了台阶后面再循环区域中的虚拟燃料氦摩尔分数分布。为了改善燃烧特性，使用各种配置在阶梯底部与氢气同时注入空气。以所有燃油喷射为基准，每个燃油喷射口周围有 2 个空气喷射流和以 2 倍燃油滞止压力喷射的空气与其他情况相比显示出最大的改进。它在降低局部燃料丰富度、缩短火焰长度和提高燃烧效率方面最为有效。