A comparative study with kerosene and hydrogen fuel in a model scramjet combustor has been carried out numerically. The effect of fuel-air equivalence ratio on the flow field properties in a cavity based mixing mechanism at a freestream Mach number of 2.08 has been probed. The investigation has been carried out in a two dimensional numerical model where a cavity of length to depth ratio of 2 is mounted on one of the walls of the flow channel. The flow field shock structure is observed to change with the change in fuel-air equivalence ratio. Total pressure loss is observed to depend both on fuel air equivalence ratio and the fuel type. The spread of fuel in the test section shows marked variation with the equivalence ratio. Performance of injector location on the fuel-air mixing is also probed during the course of the investigation. A comparative study with kerosene and hydrogen fuel in a model scramjet combustor has been carried out numerically. The effect of fuel-air equivalence ratio on the flow field properties in a cavity based mixing mechanism at a freestream Mach number of 2.08 has been probed. The investigation has been carried out in a two dimensional numerical model where a cavity of length to depth ratio of 2 is mounted on one of the walls of the flow channel. The flow field shock structure is observed to change with the change in fuel-air equivalence ratio of total pressure loss is observed to depend both on fuel air equivalence ratio and the fuel type. The spread of fuel in the test section shows marked variation with the equivalence ratio. the course of the investigation.