This paper attempts to computationally explore the influence of the shear layer, chemical kinetics model, and dimensionless thermal diffusivity ratio based on the Prandtl number on velocity field in a chamber-based supersonic combustor. The simulated results are benchmarked against empirical data available from open sources. An overprediction of 10% in comparison with the experimental measurement was observed for pressure in the flow direction at the fore edge of the chamber. The study of grid discrepancy using coarse, medium, and refined grids reveals that a moderate grid of about 1.2 million cells provides a good compromise, balancing accuracy, and computational cost. The shear layer, chemical kinetics model, and boundary surface Prandtl number significantly influence the pressure distribution along the surface of the chamber. For instance, the use of a Prandtl number of 1.2 on the boundary surface led to a 15% decrease in static pressure along the surface of the chamber, with a Prandtl number of 1.2 identified as optimal for satisfactory prediction of the flow field. The present study provides important inputs for the optimized design of a supersonic jet engine combustor. The computational findings are compared with relevant empirical data, and a critical evaluation is made based on the application of the CFD approach toward the simulation of supersonic jet engine combustor reactive flow fields.