Influence of flow control schemes of the three-strut injector on the mixing efficiency and total pressure loss for a scramjet combustor

Mixing efficiency and total pressure loss of a scramjet combustor with a three-strut injector under different flow control schemes are numerically investigated using the two-dimensional Reynolds-Averaged Navier-Stokes equations with the SST k -u model. The flow structure is analyzed in detail to reveal the mixing enhancement mechanism of the three-strut injector configuration. The results demonstrate that the three-strut injector configuration significantly improves the mixing efficiency in the ignition region of the scramjet combustor by about 20% and only about 2% increase in total pressure loss compared to the single-strut injector configuration. The strut and nozzle size distributions of the central and auxiliary struts has negligible impact on the mixing efficiency, but they can alter the flow structure. An increase in the separation distance between the central and auxiliary struts promotes the interaction between shock waves and shear layers, resulting in a reduction of the complete mixing distance by nearly 80 mm. In addition, increasing the inward injection angle of the auxiliary struts improves the mixing efficiency of air and hydrogen in the ignition zone by nearly 15%. The rise in total pressure loss caused by the flow control schemes for the three-strut injector configuration is negligible.(c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.