The present study numerically investigates the combustion characteristics and performance of a direct-connect gaseous hydrogen-fueled scramjet combustor depending on the injector scheme. A comprehensive numerical simulation was conducted with an improved delayed detached eddy simulation (IDDES) approach. The framework utilized a high-order accurate numerical scheme to ensure the high fidelity of the results. A total of ten cases were considered combining two injector schemes and five injection pressure conditions. Each injector scheme had a similar range of global equivalence ratios. Numerical results revealed the differences in the local dynamics of the counter-rotating vortex pair. The multi-injector case did not maintain the jet's systemic vortex structure, which plays a primary role in the fuel-air mixing and burning. It owes to the interactions between the jet-jet and the jet-wall surface, where the interaction leads to the loss of momentum. This characteristic of the multi-injector makes the fuel-air mixing contact surface get closer to a thin-flat layer, resulting in the flame being anchored on a flat shear layer over the entire combustor. As a result, the combustion efficiency of the multi-injector is much lower than that of the single injector under a similar equivalence ratio range. Present results indicate that the multi-injector, which is expected to increase the combustion performance by maximizing the fuel-air contact surface, may operate in contrast to its original anticipation under certain configurations and conditions. It also suggests that optimizing the combustion performance requires careful design of injector distributions considering the distances and interactions between injector-to-injector and injector-to-wall.

中文翻译：

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超燃冲压发动机燃烧室中单喷油器和多喷油器燃烧特性和性能的数值研究


本研究根据喷油器方案对直接连接气态氢燃料超燃冲压发动机燃烧室的燃烧特性和性能进行了数值研究。使用改进的延迟分离涡模拟 （IDDES） 方法进行了全面的数值模拟。该框架采用高阶精确数值方案来确保结果的高保真度。总共考虑了 10 例病例，结合了两种注射器方案和五种注射压力条件。每个喷油器方案具有相似的全局等效比范围。数值结果揭示了反向旋转涡旋对的局部动力学差异。多喷油器外壳没有保持喷气机的系统涡流结构，该结构在燃料-空气混合和燃烧中起主要作用。它归因于射流和射流壁表面之间的相互作用，其中相互作用导致动量损失。多喷油器的这一特性使燃料-空气混合接触面更接近薄-平面层，导致火焰锚定在整个燃烧室上方的平坦剪切层上。因此，在类似的当量比范围内，多喷油器的燃烧效率远低于单喷油器。目前的结果表明，预计通过最大化燃料-空气接触表面来提高燃烧性能的多喷油器在某些配置和条件下可能会与其最初预期的相反运行。它还表明，优化燃烧性能需要仔细设计喷油器分布，同时考虑喷油器到喷油器和喷油器到壁面之间的距离和相互作用。