Supersonic Combustion of Solid Fuels

Supersonic combustion of solid fuels is investigated experimentally using a rectangular-cross-section combustor in the context of understanding ignition characteristics, studying fuel regression, and determining operating conditions. Fuel grains consisted of 3D printed polymethyl-methacrylate of varying geometry. Specifically, the cavity flameholder dimensions are systematically studied to develop a flammability map. Initial examinations reveal that a longer and larger cross-sectional area of the flameholding zone in the fuel grain creates the most optimal conditions for ignition and sustained flameholding. The longer and larger flameholding zone also creates conditions for faster time-averaged regression rates. The ignition characteristics and fuel regression are also examined by varying inlet temperatures of the air, which showed that a higher inlet temperature is conducive to sustained ignition, as well as higher fuel regression rates. This work extends the available literature on supersonic combustion of solid fuels to lower temperatures than has previously been reported.