Experimental and numerical investigation of unsteady thermal reactive flow characteristics of aluminum-based nitrate ester plasticized polyether propellant across a wide pressure range

Aluminum-based nitrate ester plasticized polyether (NEPE) propellant, a high-energy solid propellant extensively employed in the aerospace industry for launch vehicles, faces significant challenges due to its unsteady reactive combustion flow characteristics not being fully understood. This lack of understanding significantly hampers its practical application and obstructs progress in deep space exploration. Therefore, it is imperative to delve into the energy mechanisms driving Al-based NEPE propellant. In our study, experimental and numerical approaches were employed to investigate the unsteady thermal reactive flow characteristics of aluminum (Al)-based NEPE propellant over a broad pressure range. The chemical kinetic model we proposed demonstrated remarkable predictive capabilities for Al-based NEPE propellant. Our findings underscore that the content and size distribution of ammonium perchlorate (AP) particles markedly influence the reactive flow intensity, affecting the burning rate of propellant. Simulation results from Al-based NEPE disk pack regression revealed that surfaces with a higher concentration of Al particles exhibited lower reactive intensity, while surfaces with a higher AP content displayed higher average transient reactive intensity. This research provides a more profound understanding of the thermal reactive processes inherent in aerospace propellants, facilitating enhanced grain design for solid propellants to achieve superior burning efficiency.