Insight into jet-regeneration composite cooling technology employed in scramjet: Significance of relative positions of two jet holes

Due to the further increase in hypersonic vehicle speed, the scramjet faces supersonic combustion and aerodynamic heating, and the conventional single cooling method like regenerative cooling has been unable to meet the heat dissipation requirements of scramjet. The composite cooling system has become the hotspot of recent research. Jet cooling has a good cooling effect at high heat flux, so the jet-regeneration composite cooling method is innovatively proposed in this study. Compared with other composite cooling systems, the jet impingement can effectively weaken thermal boundary layer thickness. Initially, the total performance of the jet-regeneration composite cooling was experimentally verified via subcritical air. Furthermore, the numerical simulation of the jet-regeneration composite cooling was also carried out after the validation of turbulence models and mesh independence. Further examples, such as the jet impingement under the effect of the initial mainstream (so-called jet-mainstream) and regenerative cooling (so-called mainstream-only), are used to illustrate the advantages of this composite cooling (so-called jet-only). The heat transfer coefficient of jet-only is 2.6 times larger than that in the case of jet-mainstream. Compared with traditional regenerative cooling, even under the influence of the mainstream, the boundary layer thickness at the stagnation point of the jet impingement can be reduced by 40 times. This work is beneficial to the design of the jet-regeneration composite cooling system.