Effect of Mach number and equivalence ratio on the pressure rising variation during combustion mode transition in a dual-mode combustor

Experiments of equivalence ratio linear increasing are utilized to employ to investigate the characteristics of combustion mode transition. For the experiments with kerosene of different increasing slope, it is found that the fuel equivalence ratio has a significant impact on pressure rising slope variation during combustion mode transition. In the experiments, the big equivalence ratio slope would not lead to slope variation of pressure rising. Similarly, this phenomenon also could not occur under some high Mach number of incoming flow experiments. Different equivalence ratio slope would lead to different border shape of the boundary layer. And the border shape of the boundary layer and normal shock wave at thermal throat restrains the main flow is an important factor to alter the pressure. Gas dynamics analysis is employed to explain the effect of the boundary layer on the pressure rising slope variation. Further, the analysis also reasonably explains that incoming flow Mach number impacts on pressure rising slope variation.