THE PERFORMANCE OF A BORON-LOADED GEL-FUEL RAMJET

The present work focuses on the possibility of combining the advantages of ramjet propulsion with the high energetic potential of boron. How-ever, the use of boron poses two major challenges. The ¦rst, common to all solid additives to liquid fuels is particle sedimentation and poor dis-persion. This problem is solved through the use of a gel fuel. The second obstacle, speci¦c to boron-enriched fuels, is the di©culty in realizing the full energetic potential of boron. This could be overcome by means of an aft-combustion chamber, where fuel-rich combustion products are mixed with cold bypass air. Cooling causes the gaseous boron oxide to condense and, as a consequence, the heat of evaporation trapped in the gaseous oxide is released. The merits of such a combination are assessed through its ability to power an air-to-surface missile of relatively small size, ca-pable of delivering a large payload to over a distance of about 1000 km in short time. The paper presents a preliminary design of a ramjet mis-sile using a gel fuel loaded with boron. The thermochemical aspects of the two-stage combustion of the fuel are considered. A comparison with a solid rocket motor (SRM) missile launched under the same conditions as the ramjet missile is made. The boron-loaded gel-fuel ramjet is found superior for this mission. NOMENCLATURE AoA angle of attack AP ammonium perchlorate CD drag coe©cient CL lift coe©cient CM pitching moment coe©cient D drag forc