Effect of a convergent nozzle on the performance of an empty cylindrical rotating detonation combustor

A cold kerosene hot air two-phase cylindrical rotating detonation combustor with nozzles with convergence ratios of 4.81 and 3.60 was studied by numerical simulation and experiments. The commercial CFD software were used to simulate and analyze the empty cylindrical rotating detonation combustor with a convergent nozzle. With the help of the ground test bench, the experimental study of a ramjet rotating detonation engine under the condition of high total enthalpy incoming flow was carried out, and the pressure signals of the isolation section, detonation combustor, and nozzle throat were obtained. The results show that when the nozzle with a small throat area is used in the rotating detonation combustor, the wave velocity is slightly increased. In the simulation, the wave velocity is increased from 1 891 to 1 899 m/s, while in the test, it is increased from 1 670 to 1 686 m/s. Increasing the convergence ratio leads to an increase in total pressure, combustion efficiency, and fuel specific impulse along the way. However, changing the convergence ratio of the converging nozzle will cause the positive shock wave at the end of the isolation section to move forward, thus stable working margin decreases.