Comparative study on the laser-induced combustion behavior and product characteristics of catalytically modified double-base propellants under varying pressures

This study investigates the ignition and combustion mechanisms of four modified double-base propellants (MODH1, MODH2, AMRDH2, AMDH3) and examines how formulation, pressure, and storage time influence combustion behavior and catalytic performance. Using a custom-designed solid propellant ignition and combustion system combined with non-contact optical diagnostics, we analyzed flame dynamics, ignition delay, combustion duration, and combustion product characteristics. Results show that under atmospheric pressure, MODH1 demonstrates a shorter ignition delay and higher combustion intensity due to the catalytic effect of magnesium oxide (MgO). MODH2 exhibits longer ignition delays and reduced intensity, attributed to catalyst degradation during aging. AMRDH2 displays enhanced combustion, especially at 1 MPa and 2 MPa, where the synergy of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and magnesium (Mg) leads to higher flame temperatures, denser flame structures, and improved efficiency. AMDH3 shows milder combustion with anthraquinone (AQ)-based energetic ionic salts offering effective catalysis and cleaner products. Increased pressure shortens ignition delay and combustion duration for all propellants, indicating enhanced reaction completeness and efficiency. Spectral analysis reveals stronger emission intensity at higher pressures, suggesting faster reaction rates and higher localized temperatures. Morphological analysis shows that MODH1 and MODH2 form honeycomb-like porous structures under high pressure, AMRDH2 develops a coral-like morphology, and AMDH3 presents a coiled structure. Elemental analysis highlights pressure- and formulation-dependent variations in elemental distribution, particularly for Mg, lead (Pb), and nickel (Ni). This work reveals the catalytic impact on combustion behavior, emphasizing catalyst stability, pressure effects, and composition-dependent combustion product characteristics, providing a theoretical basis for propellant optimization and performance enhancement.