Numerical investigation on the performance of scramjet combustor with a novel strut configuration

The design of the strut fuel injector plays an important role in the performance of the strut-based scramjet combustor. The current study numerically investigates the flow and combustion characteristics of a scramjet combustor. An in-house code was developed to compute the Reynolds-averaged Navier-Stokes (RANS) equations coupled with the SST k - omega turbulence model and the one-step reaction finite-rate/eddy-dissipation model. In order to enhance the mixing and combustion efficiency, we develop a novel double-strut concept with backward-facing steps in the scramjet combustor. Firstly, the numerical methods are validated by the available experimental data in open literature. Then we compare the mixing and combustion performance between the single strut and the double-strut. Finally, the effects of the perpendicular distance between the two struts on the mixing and combustion efficiency are also reported. The numerical results show an acceptable agreement with the experimental results. The presence of the double-strut with backward facing steps has a remarkable enhancement on the mixing degree and combustion efficiency in the scramjet combustor when compared with the original single-strut. Further, the combustion efficiency for the perpendicular distance of 4 nun is the highest one among the six cases, and the total pressure loss is relatively low. Therefore, the new configuration with the perpendicular distance of 4 mm is the optimal one within the range considered in this study.