Dual-mode ramjet/scramjet engines are considered a promising propulsion system for the next generation commercial high-speed transport flight vehicles. In this study we combine experimental measurements of high-speed (subsonic and supersonic) combustion at different operating conditions in the LAPCAT-II dual-mode ramjet/scramjet combustor with Large Eddy Simulations (LES) using finite rate chemistry models and skeletal H₂–air combustion chemistry. The combustor geometrically consists of four sections, and experiments have been realized for wall injection of H₂ in a Mach = 2 vitiated air-flow for total pressures and temperatures of p₀ = 0.40 MPa, 1414 K < T₀ < 1707 K, and a fixed equivalence ratio of ϕ=0.15. For this p₀ the combustor is over-expanded, and the transition from supersonic to subsonic flow occurs at the beginning of the fourth combustor section. The flow and combustion diagnostics include measurements of p₀ and T₀ upstream of the combustor, wall-pressure profiles and Schlieren as well as OH* chemiluminescence imaging. The computational set-up consists of the full combustor, from the nozzle into the dump-tank. The computational model is composed of a compressible finite rate chemistry LES model, using the mixed subgrid flow model and the Partially Stirred Reactor (PaSR) combustion model, together with a novel skeletal 22 step H₂–air reaction mechanism. Qualitative as well as quantitative comparisons between experiments and simulations show reasonably good agreement, but most importantly reveal a high sensitivity of both the LES predictions and the experiments to T₀. The LES results are further used to describe the underlying mechanisms of flow, wall-injection, mixing, self-ignition and turbulent combustion, and how these interrelated processes are modified by increasing the total temperature under otherwise identical conditions.

双模冲压喷气发动机/超燃冲压发动机被认为是下一代商用高速运输飞行器的有前途的推进系统。在这项研究中，我们使用有限速率化学模型和骨架H _2-结合了LAPCAT-II双模冲压喷气发动机/超燃冲压发动机燃烧室中在不同工况下的高速（亚音速和超音速）燃烧的实验测量结果以及大型涡流模拟（LES）。空气燃烧化学。燃烧器的几何形状由四个部分组成，并且已经实现了在总压力和温度p ₀  = 0.40 MPa，1414 K <  T ₀  <1707 K和温度为Mach = 2的空气流中向壁中注入H _2的实验。固定当量比ϕ＝ 0.15。对于该p ₀，燃烧器过度膨胀，并且从超音速流到亚音速流的过渡发生在第四燃烧器部分的开始处。流动和燃烧诊断包括对燃烧器上游的p ₀和T _0的测量，壁压曲线和Schlieren以及OH *化学发光成像。计算设置包括从喷嘴到卸料箱的整个燃烧室。该计算模型由可压缩的有限速率化学LES模型，混合亚网格流动模型和部分搅拌反应器（PaSR）燃烧模型以及新颖的22步骨架H _2组成。–空气反应机理。实验和模拟之间的定性和定量比较显示出相当好的一致性，但最重要的是，LES预测和实验对T _0的敏感性都很高。LES结果进一步用于描述流动，壁喷射，混合，自燃和湍流燃烧的潜在机理，以及在其他相同条件下如何通过提高总温度来修改这些相互关联的过程。