Random Packs and Their Use in Modeling High Speed Porous Flow

Random packs of spheres have been used to model heterogeneous and porous material morphologies during simulations of physical processes such as burning of coal char, convective burning in porous explosives, and regression of solid rocket propellant. Sphere packs have also been used to predict thermo-mechanical properties, permeability, packing density, and dissolution characteristics of various materials. In this work, we have used the Lubachevsky-Stillinger (LS) packing algorithm to create polydisperse packs of spheres for modeling heterogeneity in solid rocket grains. We have greatly improved upon the computational efficiency of the original algorithm by using hierarchical cells in 3D. The speed-up enables the generation of polydisperse packs of millions of spheres on serial workstations and laptops. We have statistically characterized these large packs and validated the results against published experiments. Furthermore, we have extended the LS sphere packing framework by incorporating a level set scheme to pack non-spherical shapes that are more relevant in many complex materials such as HMX and pressed gun propellants. We have obtained results for dense random packs of various convex shapes such as gel capsules, cylinders, and polyhedra. As an example application, we present preliminary results of numerical experiments of compressible, large Mach number gas permeation into packs of polydisperse spherical and non-spherical particles.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Theoretical and Applied Mechanics

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Stafford, David Shane

Contributors dc:contributor

• Thomas Jackson

• Applied Mechanics

Language dc:language

eng

Identifier

(MiAaPQ)AAI3347515

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/87752