A Stochastic Pocket Model for Aluminum Agglomeration in Solid Propellants

Abstract

A new model is derived to estimate the size and fraction of aluminum agglomerates at the surface of a burning propellant. The basic idea relies on well‐known pocket models in which aluminum is supposed to aggregate and melt within pocket volumes imposed by largest oxidizer particles. The proposed model essentially relaxes simple assumptions of previous pocket models on propellant structure by accounting for an actual microstructure obtained by packing. The use of statistical tools from stochastic geometry enables to determine a statistical pocket size volume and hence agglomerate diameter and agglomeration fraction. Application to several AP/Al propellants gives encouraging results that are shown to be superior to former pocket models.

Heterogeneous solid propellants: from microstructure to macroscale properties

“…A similar comparison has also been applied to the agglomeration ratio [21]. Here again, it seems that a microstructure-based model is more representative that a classical pocket approach.…”

Automatic sorting of point pattern sets using Minkowski functionals

“…This makes them a more complete "fingerprint" for pattern comparison [19,20]. These functionals have enjoyed marked success in astrophysics [21], soft matter [22], and fluid turbulence [23].…”

Analysis and synthesis of solutions for the agglomeration process modeling

“…Some models allow to determine additionally the function of size of agglomerates distribution. Besides, some models give the chance to ¦nd such important characteristic of process of agglomeration as a fraction of agglomerating metal [6,13,14]. It is necessary to mention the increased attention during last years to numerical modeling of distribution of a disperse phase in propellants [7, 29 31].…”

“…They are used in [10 12]. Gallier named ¤pocket¥ a congestion of initial particles of metal in propellant [13]. The similar approach is also applied in a number of other papers [8, 14 * ].…”