基于支板的超燃冲压发动机燃烧室模态转换过程参数化研究（英文）

Mode transition process in a typical strut-based scramjet combustor based on a parametric study

目的:超燃冲压发动机燃烧室中氢气的燃烧性能引起了研究者的广泛兴趣。本文旨在探讨不同压比下超燃冲压发动机燃烧室的燃烧性能以及壁面凹腔的影响,为双模态超燃冲压发动机燃烧室设计提供参考。创新点:1.研究压比变化过程中超燃向亚燃的转换过程;2.研究壁面凹腔设置对模态转换过程的影响。方法:采用数值模拟方法研究不同来流条件下,压比和壁面凹腔设置对基于支板的超燃冲压发动机燃烧室中模态转换过程的影响。结论:1.壁面喷注压强对流场结构影响很大,特别是对于亚燃到超燃的模态转换过程和燃烧性能,当壁面喷注压强大约为支板喷注压强一半时,效果最好;2.壁面凹腔能帮助稳定流场,但也会带来一定的混合效率和燃烧效率损失,同时壁面凹腔能帮助延迟从超燃模态向亚燃模态的转换时间,这也从一定程度上说明带凹腔的燃烧室更加适合于超燃模态。

The combustion performance of hydrogen fuel in a scramjet combustor has been a popular focus for scholars all over the world. In this study, the influence of the jet-to-crossflow pressure ratio on combustion performance in a scramjet combustor was investigated numerically, and the influence of a wall-mounted cavity was evaluated. The simulations were conducted using the Reynolds-averaged Navier-Stokes（RANS） equations coupled with the renormalization group（RNG） k-ε turbulence model and the single-step chemical reaction mechanism. This numerical approach was validated by comparing predicted results with published experimental shadowgraphs and velocity and temperature measurements. When the pressure of the wall-injector increases, the performance of the combustor decreases. At the same inflow condition, this may lead to a scram-to-ram mode transition. The cavity adopted in this study would prevent pre-combustion shock waves from pushing out of the isolator and help to stabilize the flow field, but it would decrease the mixing and combustion efficiencies.