Combustion characteristics of composite solid propellants under low-temperature and high-pressure conditions

This research article presents a novel exploration path concerning propellant combustion in challenging settings marked by low temperatures and high pressures. The investigation entails a methodical examination of the ignition and combustion features exhibited by propellants incorporating aluminum components. This scrutiny is conducted across a temperature spectrum ranging from −80 to 0 °C, coupled with a pressure environment of 7 MPa. As the starting temperature decreases, the propellant exhibits notable variations in its combustion behavior. Specifically, there is a substantial prolongation of the ignition delay period, with an increase of up to 171.4 %. Concurrently, the burning rate experiences a significant reduction of up to 27.1 %. This temperature shift also triggers an escalation in aluminum aggregation within the propellant, resulting in the enlargement of condensed combustion product sizes by up to 275.0 %. Furthermore, the combustion efficiency of the propellant shows a decline, reaching a maximum reduction of 19.4 %. We put forth physical mechanisms elucidating how low-temperature environments influence propellant combustion. By lowering the starting temperature, a cascading effect ensues. This includes a reduction in the surface temperature during the combustion process, which in turn diminishes radiative heat transfer mechanisms. As a direct consequence, the burning rate of the propellant experiences a notable deceleration. Cold temperatures facilitate a closer proximity between propellant constituents, augmenting the quantity of aluminum particles in the propellant falling below the critical agglomeration distance. This elevates the likelihood of propellant agglomeration, culminating in reduced combustion efficiency. This progression enlarges agglomeration size and compromises combustion efficiency, deepening our insight into propellant combustion alterations in low-temperature, high-pressure settings.