Effects of the exit convergent ratio on the propagation behavior of rotating detonations utilizing liquid kerosene

The effects of the exit convergent ratio on the propagation behavior (i.e., initiation processes and propagation characteristics) of rotating detonations utilizing liquid kerosene have been experimentally investigated by varying the exit convergent ratio from 1 to 10 (i.e., CR = 1, 1.25, 1.67, 2.5, 5 and 10) and the mass flow rate of oxidizer. Oxygen-enriched air with an oxygen volume fraction of 40% and kerosene have been used as oxidizer and fuel, respectively, which are supplied into the combustion chamber through an atomizer-slit configuration. Experimental results indicate that rotating detonation waves can be initiated and propagate with different propagation modes under different exit convergent ratios. Three different propagation modes have been obtained, i.e., a deflagration mode, an ignition failure mode and a stable detonation mode. Moreover, the results show that the convergent ratio significantly influences the propagation modes, and when the combustion chamber outlet with a smaller convergent ratio is employed, stable rotating detonation waves can be obtained easily. In addition, it is observed that the time of establishment of the detonation wave increases with the convergent ratio.