Numerical investigation on implications of four strut injectors on combustion characteristics of a Doubly-Dual cavity-based scramjet combustor

Abstract

The present study numerically investigates the implications of four strut injector on combustion characteristics of a hydrogen fueled doubly-dual cavity based scramjet combustor. Large Eddy Simulation (LES) is adopted to reveal the combustion characteristics of the doubly-dual cavity based scramjet combustor. Firstly, the fluid flow characteristics of a three strut injector are compared with four strut injector to highlight the influence of 4-strut injector. Thereafter, a separate study is carried out to investigate the influence of Mach number on the performance of the combustor. Our study reveals that the four strut injector arrangement greatly affects the shock wave interaction like, shock-shock and the shock-shear layer which leads to enhance the formation of vortices and recirculation region as compared to the three strut injector arrangement. In addition, introduction of 4-strut injectors found to result in better mixing and complete combustion as evidenced by the higher static temperature and the lesser amount of oxygen mass fraction at the outlet of the combustor.Also, the flame blow out condition is seen at the trailingedge of a strut and found to be minimum when 4 strut arrangement is use dowing to maximum value of OH mass fraction. Further, the higher air-fuel mixing rate is observed at Mach 2.5 of the free stream of their inlet which aids to stabilize the flame leading to complete combustion.