Combustion and Boundary Layer Tripping Effects of an MPIA in a Canonical Axisymmetric Scramjet Flowpath

Abstract: A canonical axisymmetric scramjet flowpath was designed and tested within the T4 Shock Tunnel at The University of Queensland. A novel aspect of this flowpath was the inclusion of a MultiPorthole Injector Array (MPIA) within a high internal contraction inlet with an area ratio of 7. Ethylene fuel was injected through MPIA and porthole injectors to examine combustion at different flight dynamic pressures, and compared with nitrogen injection as a combustion-suppressed case, in addition to the unfueled case, alongside equivalent numerical simulations. These results show steady combustion of ethylene in the axisymmetric flow path without the aid of cavity flameholders and the capability of the MPIA to trip the boundary layer to turbulent. These are significant findings that will influence the design of future scramjet systems. Keywords: Hypersonics, scramjet, supersonic combustion, multiporthole injectors, ground-testing