Investigation of a solid fuel scramjet combustor

The combustion of a solid fuel under supersonic crossflow conditions in a;scramjet configuration has been studied experimentally, self-ignition and sustained combustion of poly-methyl-methacrylate with no external aid (such as reactive gas injection or a pilot flame) were demonstrated in static tests simulating a flight Mach number of about 5 at high altitude. The appropriate inlet conditions, i.e., stagnation temperature and pressure in excess of 1200 K and 16 atm, respectively, were provided by a vitiated air heater. The diverging combustion chamber included a fore-end name stabilization zone, whose flameholding limits were determined experimentally. Plow and combustion phenomena were studied both by pressure measurements along the fuel grain and by video recording, taking advantage of the fuel transparency. Comparison between theoretical results of a one-dimensional now model with test data showed fair agreement, indicating the existence of a supersonic flow regime within the combustor. The video pictures provided temporal and spatial fuel regression rate data, using a computerized image analysis system.