Explosions of aluminum-rich materials may be more beneficial than detonation ofconventional high explosives under certain conditions not only because oxidizer-aluminummixtures are usually more energetic than homogeneous explosives but alsobecause the expanding explosion products are capable of entering into reactions with theambient water to release large amount of additional heat. To produce intense pressurepulses in range of few kilobars in amplitude and tens of milliseconds in duration thecharges must either detonate or burn in a fast deflagration mode, which in somesituations can be even more efficient because provides better conditions for mixing of theproducts with ambient oxidizer than does detonation. Significant drawbacks of aluminum-oxidizermixtures are that their combustion products contain small amount of gaseouscomponents and that without appropriate additives it is hard to fabricate densemechanically strong charges with controlled porosity. Thus optimal compositions shouldcontain additives (kerosene or nitromethane) that serve as both a gasprovider andcompacting component.This study presents results of experimental and numerical modeling of fast convectiveburning and low velocity detonation in the aforesaid mixtures. Ammonium perchlorate-basedmixtures which contain 50 and more wt. % of fine aluminum powders andnitromethane as an active and compacting component were investigated. It was shownthat the studied processes, due to the active components of the mixture partially burndown, provide fast preheating of excess aluminum inside the charge and high-speed (at alevel about 100 m/s) injection of expanding reactive products and mixing them withambient water. Besides, the behavior of the charges placed in underwater conditions hasbeen studied experimentally in water basin as well as by theoretical modeling. Theinvestigation results shed light on processes taking place inside the reacting cloud and oncompression wave formation in external volume. The model task of ice breaking wasused to discuss efficiency of the possible real charges.
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