2D model for unsteady burning heterogeneous AP/binder solid propellants

The burning of a periodic sandwich of the solid oxidizer, ammonium perchlorate (A) and solid fuel, HTPB is modeled by considering two-dimensional energy balances in both the solid and gas phases, two-dimensional gas species concentration, considering a reduced chemistry model for three global reactions and eight chemical species. Full heat coupling between the solid and gas phase allows the prediction of the AP, binder, and average regression rates. Flame structure including the AP decomposition flame and the diffusion flames with the binder are predicted to occur within regions ranging from 10 μm to 200 μm. Solutions are presented for various AP/binder ratios, at solid rocket pressures, ranging from 40-100 atm. Parametric studies identify the sensitivity of the burning rates to the chemical kinetics constants and the pyrolysis relations, as well as the solid-phase heat exchange coefficient, α_s.