关键词: 超燃冲压发动机, 凹腔, 超声速, 液体煤油, 液滴碰壁

Abstract:

The liquid kerosene jet is generally injected upstream of the cavity， and the fuel distribution inside the cavity is critical to the subsequent ignition and combustion process， so the transport process of spray into the cavity has always been a concern. Based on the two-phase Large Eddy Simulation method under the Euler-Lagrangian framework， this paper numerically studies the mixing process of liquid kerosene jet in a cavity-based supersonic combustor. The incoming flow had a total pressure of 1.0 MPa， a total temperature of 900 K， and an inlet Mach number of 2.0. Considering the evaporation of kerosene at room temperature and the collision of droplets with the wall in the combustor， this paper focuses on the process of spray entrainment from the lower wall of the combustion chamber into the cavity. After the liquid droplets are injected， they diffuse downstream under the action of the incoming flow. Most of the liquid droplets directly cross the cavity and transport downstream in the mainstream area above the cavity， with a small amount （about 5.2%） of liquid droplets being entrained into the cavity. The entry of droplets into the cavity mainly includes two paths： one is through the shear layer at the front edge of the cavity， and the other is through the rear edge of the cavity. On these two paths， droplets collide with the wall upstream of the cavity and the trailing edge of the cavity to generate splashed droplets， which are then widely distributed in the cavity.

Key words: scramjet, cavity, supersonic, liquid kerosene, droplet/wall collision