Numerical study on atomization and evaporation characteristics of preheated kerosene jet in a rotating detonation scramjet combustor

Abstract

Preheated kerosene injection is one of the fuel supply methods for a rotating detonation scramjet engine. The injection and evaporation of preheated kerosene were numerically investigated in an expansion configuration combustor with intake air at a speed of Mach 2 at various fuel temperatures for the first time. The Euler-Lagrangian method was used to describe the gas–liquid two-phase flow phenomenon. The random trajectory model was used to track the droplet movement process, and the infinite thermal conductivity model was used to describe the evaporation process. The numerical analysis of preheated kerosene injection atomization in supersonic inflow under constant liquid–gas momentum flux ratio was performed. The results reveal that the penetration depth of various thermal jets in the combustor changes slightly with a constant liquid–gas momentum flux ratio, independently of the kerosene temperature and liquid–gas coupling influence in the mainstream zone. The shape of the outer edge of the liquid mist evidently varies in a disordered manner. Using preheated kerosene as the fuel of the rotating detonation scramjet can increase the mixing degree of gas–liquid two-phase jets and accelerate the evaporation of droplets. Moreover, the fragmentation and atomization effects of thermal kerosene droplets are significantly improved. The analysis demonstrates that preheated kerosene injection may be beneficial to ignition and contributes to the self-sustainment of the detonation waves in the engine.