A Review on Scramjet Engine

Abstract

Combustion occurs at supersonic speeds in a scramjet engine. Lower air residence time is the factor affecting proper fuel–air mixing, flame propagation and cooling of engine components. This current study includes systematic review of fuel–air mixing inside the combustor through various design changes and augmentations and strides to present at the future scope of this technology. Methods of sufficient and rapid fuel–air mixing used are also studied. Various methods of augmentation applied to the geometry of combustion chamber are presented which are developed for greater fuel–air mixing. Enhanced mixing time in real-time situations is studied by hypothesis of the fluid flow inside the combustion chamber using CFD analysis for air speeds higher than Mach 1.6. Fuel injectors placed in upstream, studied through CFD analysis, have also been included in this review. Recent development in fuel injector is studied too. Single and multiple fuel injectors are used to compare the mixing efficiency with variation in Mach speeds and inlet angle of air inside the combustor. Liquid and gaseous fuels are considered for better fuel–air mixture, and their secondary function as a cooling system is assessed.