Experimental and numerical investigation on combustion characteristics of double large cube RDX-based NEPE solid propellant burning in an atmospheric environment

When two solid propellant fire sources are in close proximity, their combustion characteristics may interact, leading to the phenomenon known as dual-fire source solid propellant fire. This study aims to comprehensively evaluate the combustion behavior of two NEPE (Nitrate Ester Plasticized Ether) solid propellant fires in an open-air environment. Experimental findings indicate that the combustion dynamics of dual-fire source solid propellants are significantly influenced by factors such as propellant size, inter-source spacing, and environmental wind conditions. Various distinctive phenomena were observed during the combustion process, including independent flame development, flame fusion, and intermittent independent flame decay. These phenomena resulted in notable fluctuations in flame temperature, with temperatures between dual-fire sources being lower compared to their single-fire source counterparts. Additionally, a three-dimensional combustion-flow coupling computational model was developed, integrating models for random particle trajectories, vortex dissipation, and radiation. The numerical simulations effectively replicated the observed effects, showing that increasing environmental wind speed enhances the occlusion behavior between the two propellant flames, leading to reduced flame height and diminished flame radiation intensity.