Combustion Behavior of HTPB Propellant Containing Ammonium Oxalate under Rapid Depressurization

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 respectively. The parameters included steady-state burning rates, critical depressurization extinguishment boundaries, and transient flame evolution processes. The results show that the critical depressurization rate (dp/dt) required for propellant extinguishment linearly increases with the initial pressure ( p0 ). Adding 2% ammonium oxalate into HTPB/AP propellant. the depressurization relief region reignition area within 0. 5 MPa to 2. 51 MPa is reduced by 18. 74% and the critical depressurization rate is decreased by 6.87% -25. 18%. The steady-state burning rate decreased by 6.5% 20. 5% in the range at 0. 1 9 MPa. and increased to 13.9% 26.6% in the formula with 4% ammonium oxalate. The consistency between steady-state and transient combustion 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. © 2024 China Ordnance Industry Corporation. All rights reserved.