In order to investigate the controllability of ignition and extinguishment of a series of low burning rate propellants containing ammonium oxalate(mass fraction 0-4％),the combustion parameters of the propellants under steady-state and transient conditions were measured by using a high pressure laser ignition platform and a magnetic pressure relief test engine re-spectively.The parameters included steady-state burning rates,critical depressurization extinguishment boundaries,and transi-ent flame evolution processes.The results show that the critical depressurization rate(dp/dt)required for propellant extin-guishment linearly increases with the initial pressure(p0).Adding 2％ammonium oxalate into HTPB/AP propellant,the depre-ssurization relief region reignition area within 0.5 MPa to 2.51 MPa is reduced by 18.74％and the critical depressurization rate is de-creased by 6.87％—25.18％.The steady-state burning rate decreased by 6.5％—20.5％in the range at 0.1-9MPa,and in-creased to 13.9％—26.6％in the formula with 4％ammonium oxalate.The consistency between steady-state and transient combus-tion results indicates that ammonium oxalate helps HTPB/AP-based propellants achieve extinguishment after depressurization.This effect is attributed to its strong inhibition of AP decomposition and significant decomposition heat absorption.
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