The mode transition characteristics in a dual-mode combustor at different total temperatures

Abstract

The mode transition experiments in a dual-mode combustor were carried out under the conditions of total pressure 1.05 MPa, Mach number 2.0 and total temperature 1285 K, 1085 K and 885 K. The processes of mode transition of the combustor under different total temperature conditions were studied. The connection between the fuel equivalence ratio, the ratio of the peak pressure of the combustor to the inlet total pressure of the isolator, and different combustion modes was analyzed. The study showed that the lower the total temperature of the incoming flow and the higher the fuel equivalence ratio, the higher the dimensionless wall pressure, the more easily the shock train to disturb the upstream of the isolator, the more backward position of the choked thermal throat, and the closer the combustion tended to the ramjet mode; The results showed that there were pure scramjet mode, dual-mode scramjet mode, dual-mode ramjet mode and the combustion state caused the pressure disturbance that spread to the entrance of the isolator with the increase of the fuel equivalence ratio. The dimensionless peak pressures when mode transition occurred were 0.25, 0.40 and 0.5, and did not change with the change of the total temperature.