International Journal of Thermofluids (Nov 2022)
Impact of passive fuel injections techniques in the flow field of the scramjet combustor
Abstract
The development of scramjet technology has paved the path of possibilities for researchers to develop light-weighted space missions in the years to come. Many countries around the globe have already tested successful scramjet engines. The researchers are making continuous efforts to improve the combustor design by improvising turbulence inserts and flame holders in the combustor. One such improvisation is the introduction of strut into the parallel-cavities combustor. The research paper uses computational fluid dynamics to investigate the effect of internal flow field variables on a strut and cavity-based scramjet combustor. The current work presents a comparative study by analyzing two different scramjet combustor configurations namely case A and Case B to understand the effect of presence of strut in the cavity combustor. The velocity and static pressure profiles are analyzed at different streamwise locations. At x = 70 mm, the velocity values are reduced to lower magnitude for case B as compared to case A and the static pressure values towards downstream detoriates with reduction in intensity of shock waves. It is seen that the magnitude of velocity values and pressure values increases with increase is Mach number. The high-pressure values are observed for M-2.75. A performance assessment of the combustor is carried out for both the configurations, maximum combustion and mixing performance is obtained for M-2.52 for case B as compared to Case A. The paper further analyses three different fuel injection locations namely fuel injection strut only, fuel injection through the wall only and fuel injection through both strut+wall recognized as the case I, II, and III respectively. From various flow-field parameters analysis, it is seen that the production of eddies and vortices in the combustor region indicates proper mixing which is observed for case I. On studying the mass fraction concentration of H20 species for all the cases it is observed that the H20 species is increasing in the lateral direction which indicates that the combustion efficiency is incrementing in the same direction. The maximum combustion and mixing efficiency is observed for case I than the other two cases.
