Effects of total pressure on mode transition in a dual-mode combustor

Abstract

The mode transition experiments of the dual-mode combustor were carried out under the conditions that the total pressure was 600 kPa, 700 kPa, 800 kPa and 900 kPa, the total temperature was 810 K, and the Mach number was 2.0. According to the wall pressure of the combustor measured in the experiment, the distribution of other airflow parameters of the combustor were obtained through the one-dimensional performance calculation method. The processes of mode transition of the combustor under different total pressures were studied. The study show that the dimensionless peak pressure of the combustor increased with the increase of the entrance total pressure under the same fuel equivalence ratio; the larger the total pressure, the smaller the fuel equivalence ratio required to reach the same dimensionless peak pressure. The results show that there were pure scramjet mode, dual-mode scramjet mode, dual-mode ramjet mode and the combustion state that the pressure disturbance had spread to the entrance of the isolator with the increase of the fuel equivalence ratio. The dimensionless peak pressures of the combustor when mode transition occurred were 0.25, 0.41, and 0.5, and did not change with the change of the total pressure of the incoming flow.