NUMERICAL INVESTIGATION ON THE INFLOW MACH NUMBER VARIATIONS IN A STRUT INJECTED CAVITY-BASED SCRAMJET COMBUSTORS

Abstract

The effect of enhancing the air inflow Mach number of a strut-injected cavity incorporated into a scramjet combustor is numerically studied. The computational investigations are performed using the commercial code Ansys Fluent software. The simulation is carried out using the SST k-ω turbulence model with single-step reaction chemistry and a two-dimensional planar model using the Reynolds-averaged Navier-Stokes (RANS) method. The cavities are positioned downstream of the strut injector that are fixed to the top and bottom walls. This configuration enables the analysis of the shock wave pattern and its correlations with shear layer mixing features. Three inflow Mach numbers are opted for the present investigation, i.e., Mach 2.0, 2.5, and 3.0. The investigations are accomplished on the flow pattern, static pressure, and temperature distributions. Performance analyses for the twin cavity designs that fit into the German Aerospace Center (DLR) scramjet are performed throughout the entire combustor length. A reduction in combustion chamber length by 20% and complete combustion is achieved from the twin cavity configuration as compared to the baseline model. The overall pressure drop is increased around 23% due to the formation of additional shock waves from the cavities. Moreover, the combustion zone prolongs along the flow direction due to the increase in the inflow Mach numbers.