Experimental Study on Mode Transition in a Dual-Mode Scramjet Combustor

Abstract

ABSTRACTAn experiment of mode transition within a supersonic combustor with a variable fuel flow rate was carried out under the total temperature of 1085 K, total pressure of 1.05 MPa and Mach number of 1.95 of the conditions of the exit of the inlet. According to the wall pressure of the combustor measured by the experiment, the distribution of other airflow parameters in the combustor was calculated by a one-dimensional analysis method. The process of the mode transition in the same test with a variable fuel flow rate was studied and the relationship between the combustion mode transition and fuel equivalence ratio was analyzed. The results show that there were a pure scramjet mode, a dual-mode scramjet mode, a dual-mode ramjet mode and a combustion state that the pressure disturbance had arrived at the entrance of the isolator with the change of the fuel equivalence ratio. During the experiment, the ratio of the peak pressure of the combustor to the total pressure of the inlet of the isolator is 0.28, 0.4, and 0.5, respectively. In addition, the study also found that the equivalence ratios converting from pure scramjet mode to the ramjet mode were a little higher than those of the opposite process.