Bubble loading characteristics in underwater explosions of CL-20-based aluminized explosives: a novel aluminum combustion energy release model

Aluminum powder is the most commonly employed metal fuel in aluminized explosives. The energy release from aluminum powder combustion significantly influences the underwater explosion bubble loading characteristics of aluminized explosives. Accurate determination of bubble loading parameters is crucial for optimizing explosive formulation design and enhancing energy utilization efficiency. In this study, we developed a non-isothermal combustion model for aluminum powder with derived governing equations under detonation conditions. A novel equation of state (JWL-Al EOS) was formulated for detonation products incorporating aluminum secondary combustion. This theoretical framework was integrated with bubble dynamics equations to establish a computational method for underwater explosion bubble loading, which was experimentally validated through systematic testing. The effects of explosive composition parameters and water depth on the underwater explosion bubble loading of CL-20-based aluminized explosives were systematically investigated. Our investigations revealed that the proposed computational method for bubble loading demonstrates high accuracy. The Al/O ratio modulates the complete bubble pulsation cycle, where the first bubble period demonstrates an initial increase followed by reduction as the Al/O ratio increases, while aluminum combustion rate shows monotonic decline. Conversely, increasing water depth shortens the first bubble period but accelerates aluminum combustion rate. Bubble energy exhibits positive correlation with water depth, but increases and then decreases with rising Al/O ratio.