MULTIPHASE CHEMISTRY CONSIDERATIONS AT THE SURFACE OF BURNING NITRAMINE MONOPROPELLANTS

The surface reaction zone of a solid propellant is increasingly acknowledged as imparting major, if not dominant, characteristics to combustion, An overview of this evolving issue is given. Chemistry considerations associated with the multiphase surface layer of the nitramine monopropellants HMX and RDX are discussed critically. These include global rates, specific decomposition and exothermic reactions, evaporation, and surface temperatures, A chemistry description is offered that involves the competition of two decomposition branches and one strongly exothermic reaction. Based simply on rationally derived reaction rates, reasonable deductions may be made about the surface temperature and reaction-zone thickness during combustion of HMX and RDX.