Mecanism of flameholding in plasma-assisted supersonic combustor

International audienceThis paper is focused on the study of mechanisms of plasma impact on flameholding in a confined supersonic flow. Fuel (gaseous hydrogen or ethylene) was injected through five circular orifices all in a row across the span and inclined at 25° from the normal in the upstream direction. The combustion process was initiated and sustained by near-surface electric discharge. The row of electrodes was placed 15mm upstream of the row of injectors, each injector is in line with an electrode. A two-zone mecanism of flameholding was observed: i) so called "cold" combustion takes place in the first zone, where plasma-induced fuel conversion and relatively small heat release occurs, ii) common "hot" combustion proceeds in the second zone, where combustion is completed or almost completed with high level of heat release. The following step of this study is spreading out JIHT-RAS approach of plasma assistance to the new supersonic combustor of ONERA, where higher incoming air flow temperature can be reached. Preliminary experimental results without plasma assistance at ONERA's facility and the design of a new plasma/injection module are presented