Study on the Initiation Mechanism of Non‐Premixed Shock Induced Combustion in Supersonic Propellant Gas Jet

Abstract

AbstractThe reflection of a supersonic propellant gas jet always happens during the firing of the weapon system of aircraft. The reflection induces complex non‐premixed shock induced combustion. It is of great importance to investigate the initiation mechanism of the combustion in the supersonic jet of propellant gas. The mechanism is vital for the design of any suppression method of the secondary combustion. To investigate the combustion in the reflected supersonic jet, a solid propellant combustion model and a numerical model based on compressible multispecies Navier‐Stokes equations are established. A detailed reaction mechanism consisting of 9 species and 12 reactions is utilized for the combustion of the propellant gas. Based on the models, the supersonic precursor flow field and the supersonic propellant gas jet flow are obtained and discussed. A secondary jet is observed which has not been reported before. A sandwich structure is proposed to reveal the initiation of the combustion. The oxygen supply in the secondary jet is found to be dominated by a vortex. An inert gas atmosphere can be adopted to suppress the mass transfer at the contact surface. Special devices could be designed to suppress the formation of the vortex in the secondary propellant jet.