Abstract In this study, numerical simulations were performed to investigate mode transition characteristics in a scramjet engine. The effects of different fuel injection strategies and equivalence ratios on the flow field were studied. The results showed that under relatively low inflow temperatures condition, when employing single-side fuel injection strategy, increasing the equivalence ratio would have negligible influence on the combustion flow field. Meanwhile, at high inflow temperatures, increasing equivalence ratios would reduce the velocity at the isolator outlet, which would not trigger mode transition as well for single-side fuel injection strategy. With double-side fuel injection strategy, under high inflow temperature condition, however, increasing the equivalence ratio could induce mode transition from the scramjet mode to the ramjet mode in the combustor.
Zhang et al. (Tue,) studied this question.