The transition from particle flamelet burning to premixed flame burning of
ammonium perchlorate (AP)/hydrocarbon (HC) binder propellants is identified
with detachment of the oxidizer/fuel (O/F) flamelet from the stoichiometri
c Lip of the diffusion field over the AP particle. The conditions (pressure
, particle area, local stoichiometry) for detachment are revealed by singul
ar regions of the burning rate versus pressure curves for selected bimodal
propellants.