Effect of the ammonium perchlorate particle size on its burning rate and combustion limit in terms of pressure

A model of ammonium perchlorate combustion is considered, which takes into account the complicated mechanism of its conversion: volume exothermal decomposition and surface processes (endothermal sublimation and redox reactions with heat release). Within the framework of an approximate macrokinetic description, analytical expression for the burning rate and heat balance on the burning surface are derived. Critical phenomena inherent in combustion are analyzed. It is shown that combustion failure occurs if the total thermal effect of the surface process is negative. The calculations demonstrate the agreement of the results on the burning rate and combustion limits with experimental data for ammonium perchlorate with different particle sizes.