A detailed high fidelity numerical experiment is conducted on a 3D hypersonic air-breathing propulsion engine that integrates a small pulse detonator as an innovative concept to aid supersonic cold ignition. The 3rd-Order unsteady hybrid-LES turbulent analysis closely replicates an azimuthal slice of the HiFire-2 internal flow path to determine its feasibility and performance as a supersonic combustion augmenter and forthcoming development. Preceding two-dimensional efforts using a hydrogen-oxygen mixture on the same detonator upstream of the cavity supported the initial design concept. Herein, an analogous combustor utilizes a stoichiometric CH_(4(g))+air detonation as a means to augment the fuel penetration, mixing characteristics, and early ignition process of a C_2H__(4(g)) fueled supersonic combustor. After an asymptotic solution of the cold-fueled scramjet is achieved, the analysis is subdivided into three phases detailing the cycle. During the first section (Phase-Ⅰ), the resident flow in the open tube is purged into the combustor. The flow properties in the tube are initialized at the isolator conditions for the mixture to evolve the pulse, simulated at the head of the tube prior to detonation. Secondly (Phase-Ⅱ), the tube is filled with premixed gaseous Ethylene and oxygen. And finally (Phase-Ⅲ), the expulsion of the detonated products open into the scramjet combustor after ignition and DDT (Detonation to Deflagration Transition). The numerical simulation assumes finite-rate conditions with a reduced chemical mechanism to include both the Ethylene-oxygen and -air mixtures to model the pulse detonation and the scramjet fuel flow correspondingly.
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