Effect of injection scheme on asymmetric phenomenon in rectangular and circular scramjets

The asymmetric separation has a crucial effect on the performance of the scramjet. In this study, the asymmetric separation and combustion in both rectangular and circular scramjets are investigated numerically, and the effect of injection scheme is analyzed. The characteristics of the flow field are analyzed based on sufficient code verification. In the rectangular scramjet, the sep-aration tends to occur in the corner due to the corner boundary-layer effect. The separation is asym-metric and only two corners have serious separation. The fuel penetration depth in the separation zone increases and the combustion is intensified. When the injection scheme is uniform, both the combustion and separation become weak. In the circular scramjet, the separation and combustion are basically axisymmetric in the scramjet with one-row injection scheme. The asymmetric combus-tion becomes obvious in cases with multi-row injection scheme. When the injection orifices dis-tribute intensively on the top and bottom sides, the strongest and weakest separations occur near these two sides respectively. When the distribution of orifices becomes uniform, the direction of sep-aration cannot be predicted. For multi-row cases, the nonuniform injection scheme could result in violent combustion and asymmetric flow structures compared with the uniform injection scheme.(c) 2022 Chinese Society of Aeronautics and Astronautics. Production and hosting by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).