Numerical Study of the Cavity Geometry on Supersonic Combustion with Transverse Fuel Injection

Abstract

The small residence time, in designing the engine of a supersonic aircraft, presumed to have a very important character in combustion. At hypersonic flight, the flow is supersonic while entering in the combustor to avoid excessive heating and fuel is essentially to be injected, mixed and combusted entirely within a short residence time of the order of millisecond. In order to resolve the restrictions given by short residence time, numerous studies have been carried out to suggest the concepts of injection, among which, the transverse fuel injection in a combustor with a cavity is being used in several engines. This paper describes the numerical study of the combustion enhancement with hydrogen fuel injection in a transverse aperture nozzle into a supersonic hot air stream. Several cavities with single and dual steps with different cavity wall angles are analyzed. Eddy dissipation concept model with detailed hydrogen-air combustion with 21 reactions and 9 species transport has been applied to numerically simulate the reacting flow of hydrogen fuel scramjet combustor. The mixing enhancement, static pressure and combustion efficiencies are analyzed for different cavity geometries.