Effect of Gas Addition on Liquid Kerosene Combustion in a Scramjet Combustor

Abstract

Experiments were conducted at Mach 2.52 to investigate the effect of gas addition on the mixing and combustion characteristics of the liquid kerosene in a scramjet combustor. Two different combustion modes (scram mode and ram mode) were achieved by varying the equivalence ratio. Flowfield diagnostic techniques, such as shadow visualization and wall pressure measurement, and Proper Orthogonal Decomposition analysis were employed to investigate the complex supersonic gas– liquid two-phase combustion flowfield. It is found that, compared to the pure high-pressure kerosene, the gas-added kerosene can achieve better combustion performance at low injection pressure. The gas addition increases the fuel-jet penetration depth and promotes flowfield fluctuations. The gas–liquid two-phase instability induces large-scale vortices within the fuel-jet shear layer. The diffusion and mixing of kerosene are enhanced by the large-scale vortices, and the rapid and intense combustion of kerosene is realized.