Investigation of a Solid Fuel Scramjet Combustor

Abstract

The combustion of a solid fuel under supersonic crosse ow conditions in a scramjet cone guration 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 e ame ) were demonstrated in static tests simulating a e ight 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 e ame stabilization zone, whose e ameholding limits were determined experimentally. Flow 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 e ow model with test data showed fair agreement, indicating the existence of a supersonic e ow regime within the combustor. The video pictures provided temporal and spatial fuel regression rate data, using a computerized image analysis system. Nomenclature