Combustion of ammonium nitrate-based compositions, metal-containing and water-impregnated compounds

Ammonium nitrate (AN), an inorganic solid oxidizer used in rocket propulsio n decades ago, has been enjoying a new prosperity. The main reasons favorin g its return are that it produces environmentally friendly combustion produ cts, it is very cheap, and it is a safe energetic material. The principal o bjectives of this work are to improve the general understanding of pure AN combustion, clarify the burning properties of a broad range of AN-based for mulations, and elucidate some instability effects of pure AN, as well as AN -based propellant burning. Experiments were performed on several categories of AN-based compositions: neat AN burning as a solid monopropellant, with minor additives to promote decomposition chemical reactions; mixtures:of AN with organic substances including trinitrotoluene; solid mixtures of AN wi th metallic powders;:and AN water solutions with an organic fuel (also call ed water-impregnated compositions). Preliminary results indicate that, up t o pressures of the order of hundreds of atmospheres, the main reactions res ponsible for the heat release occur:mostly in the condensed phase. At highe r pressures, the gas phase flame plays an important role in controlling the burning rate.