Influence of Several New Burning Rate Modifiers on the Combustion Performance of NEPE Composite Solid Propellants

To investigate the effects of two new burning rate modifiers on the combustion performance of NEPE composite solid propellants, eight types of NEPE propellants containing the two modifiers and their composites were prepared. The burning rates of the propellants under 10—30MPa were measured by using linear scanning real-time measurement method. The thermal decomposition processes of selected propellants and their components were tested by differential scanning calorimetry(DSC). High speed photography was used to capture the combustion process of propellants and record their ignition delay time. Some propellants were quenched and their quenched surfaces were observed by using scanning electron microscope(SEM). The morphology and particle size of condensed combustion products at 10MPa and 30MPa were analyzed. The results showed that, within the tested pressure range, both the copper-containing compound(Cu*)and boron-containing compound(B*)slightly reduced the pressure exponent of the propellants burning rate, the composite modifier formed by combining Cu* and B* significantly decreased the pressure exponent by approximately 34%. The composite modifier altered the thermal decomposition pathways of AP and RDX, which promoted pronounced aluminum agglomeration, and prolonged the residence time of aluminum on the combustion surface. These effects collectively intensified the combustion of the NEPE propellants and reduced their ignition delay time.