Numerical simulation on effect of equivalence ratio on flow field and combustion characteristics of supersonic combustor with cavity under the condition with/without chemical reactions was conducted by adjusting the fuel injection pressure to reach a certain equivalence ratio value.It is found that increasing equivalence ratio enhances combustion backpressure

expands the upstream boundary layer separation zone

and pushes shock train to the entrance of the combustor gradually.Also

enlarging equivalence ratio increases jet penetration depth gradually.In the field near fuel injector

mixing performance was obviously enhanced by increasing equivalence ratio

while in the field far away from fuel injector

little effect was induced by equivalence ratio.In the aspects of total pressure loss and cavity drag coefficient

they had proportional relationships with equivalence ratio.