Modeling of Hot Fragment Conductive Ignition of Solid Propellants With Applications to Melting and Evaporation of Solids

A comprehensive theoretical model has been formulated for studying the degree of vulnerability of various solid propellants being heated by hot spall fragments. The model simulates the hot fragment conductive ignition (HFCI) processes caused by direct contact of hot inert particles with solid propellant samples. The model describes the heat transfer and displacement of the hot particle, the generation of the melt (or foam) layer caused by the liquefaction, pyrolysis, and decomposition of the propellant, and the regression of the propellant as well as the time variation of its temperature distributions. To validate partially the theoretical model in the absence of the necessary chemical kinetic data, an ice melting and evaporation experiment was designed and conducted. These experiments provide features of the conductive heating, melting, and evaporating processes. Calculated results compare well with experimental data in temperature–time traces, spall particle sinking velocity, and displacement.