Combustion efficiency improvement for scramjet combustor with strut based flame stabilizer using passive techniques

Abstract In a Supersonic combustion ramjet (Scramjet) engine, combustion occurs at supersonic velocity as incoming air remains supersonic. Scramjet engines have complex flow phenomena taking place inside the combustor. In a scramjet combustor, mixing and combustion should take place within few milliseconds. In the present study, two additional trailing struts with no fuel injection are placed a short distance downstream of the fuel injection strut. Effect on combustion performance using these strut-based flame stabilizer configurations are assessed. Reynolds averaged Navier-Stokes equations are solved with turbulence model and species transport equations. Validated results of the single strut are compared with the different strut configurations. It is found that the placement of trailing struts have a vital role. High-pressure zones, shock reflections, recirculation region, and expansion fan in between combustion region and the trailing struts enhance the combustion efficiency. Strut configuration introducing high-pressure regions outperformed other strut configurations due to the formation of a strong recirculation region in the core combustion region. Combustion efficiency is found to have a maximum improvement of 67.14% compared with single strut-based flame stabilizer. Total pressure loss also increased due to the introduction of additional struts.