Combustion modeling of composite solid propellants with finite peclet number

A combustion model has been formulated to solve the burning rate eigenvalue problem for a composite solid propellant, similar to what has been done previously for homogeneous energetic solids. A two-step (high activation energy condensed phase decomposition followed by low activation energy gas phase heat release) model has been extended from one to two dimensions for non-premixed composite solids. Gas phase streamwise diffusion (the primary driving force for solid pyrolysis), has been accounted for by including finite Peclet number. The results show that the value of the Peclet number (which plays the role of non-dimensional burning rate) is constrained to a reasonably small interval by the eigenvalue expression obtained from activation energy asymptotic analysis of the condensed phase thermal decomposition zone. The present model is relevant to materials where diffusion flame and particle size effects are minimal such as nitramine composites.