Investigation on transient process of supersonic combustion and flow based on a multi-cavity combustor fueled with kerosene

In order to explore the process of combustion and flow based on a multi-cavity combustor, transient method is used to numerically investigate the supersonic combustion characteristics of liquid kerosene. The numerical results show that an approximate normal shock is pushed back to the isolator inlet as the heat release from combustion proceeds. The maximal ratio of pressure increase is up to 3.77, and the flowfield reaches steady within 22ms. Track of kerosene droplet in the upstream cavities presents strong transient characteristics. Its movement direction matches the pressure in local flow time. Penetration depth of droplet near the up cavity is obviously larger than that of the down cavity, and the droplet number of the former is much more than that of the latter. The total pressure recovery coefficient in the combustor outlet is equal to 47.09%, which is close to the experimental value 47.50%. The combustion efficiency is up to 72.91%, which displays the advantage of a low total pressure loss with a good combustion characteristics for the multi-cavity-based combustor. Mass entrainment rate where cavity located at the expanding surface is larger than that of the level surface, indicating that the expanding surface is beneficial to enhance the mass entrainment between the fuel in the cavity and the mainflow air. Numerically predicted static pressure on the side, up and down wall of the combustor has a good agreement with the experimental datum.