A New Al Agglomeration Model of Coupling Microscale Propellant Combustion and Its Microstructure: NEPE Propellant as a Case Study

ABSTRACT In this study, a new statistical model is introduced to predict the distribution of aluminium (Al) cluster sizes within nitrate ester plasticized polyether (NEPE) propellant. The methodology involves using a sequential algorithm to populate a cubic space with random spheres, effectively representing the microstructure of Al‐based NEPE propellant. The ‘Pocket model’ previously established by Cohen and Beckstead, in conjunction with a dual‐slicing technique, is utilized to derive a statistically reliable AP intercept. This intercept serves as a measure for the scale of ‘Pockets’, facilitating the management of varying sizes in the heterogeneous propellant structure. Furthermore, Price's leading edge flame (LEF) model is integrated, positing that LEF predominantly drives the formation of Al clusters laterally. In the vertical direction, the residence time of Al particles is considered a significant factor. When both factors align, agglomeration occurs. This study represents the first comprehensive attempt to model the pronounced agglomeration phenomenon in Al‐based NEPE propellant. Comparison with experimental data shows a satisfactory alignment, though some discrepancies highlight areas for further refinement of the model.