The effect of nozzle contraction ratio on the propagation of rotating detonation waves in subcritical kerosene

To investigate the influence of nozzle contraction ratio (ratio of nozzle outlet area to front cross section of nozzle contraction section) on the propagation characteristics of subcritical kerosene Rotating Detonation Waves (RDW), experimental methods such as high-frequency pressure sensors and voltage stabilizing sensors were employed to analyze the establishment process of the RDW. By varying the nozzle contraction ratio, the effects of changes in the nozzle outlet area on the establishment and propagation of the RDW were analyzed. During the experiments, the air flow rate was maintained at 1500g/s, the kerosene mass flow rate was 100g/s, the total air temperature was 600K, and the equivalence ratio was set to one. The research results indicate that as the nozzle contraction ratio increases, the combustion pressure gradually decreases. The propagation speed of the RDW initially increases and then decreases, and the ignition time follows a similar trend. Although the combustion chamber pressure reaches its maximum at a nozzle contraction ratio of 0.13, the ignition time and propagation speed of the engine are significantly slowed down, which is not conducive to the initiation and propagation of the RDW.