Packing fraction of clusters formed in free-falling granular streams based on flash X-ray radiography

TL;DR

This study investigates how particle shape influences cluster formation and packing density in free-falling granular streams using flash X-ray radiography, revealing shape-dependent differences in cluster growth and structure.

Contribution

It provides the first experimental analysis of packing fractions and coordination numbers in free-falling granular streams with spherical and irregular particles.

Findings

Irregular particles form larger, less densely packed clusters.

Packing fractions correspond to coordination numbers below 6.

Irregular particles evolve faster and form larger clusters.

Abstract

We study the packing fraction of clusters in free-falling streams of spherical and irregularly shaped particles using flash X-ray radiography. The estimated packing fraction of clusters is low enough to correspond to coordination numbers less than 6. Such coordination numbers in numerical simulations correspond to aggregates that collide and grow without bouncing. Moreover, the streams of irregular particles evolved faster and formed clusters of larger sizes with lower packing fraction. This result on granular streams suggests that particle shape has a significant effect on the agglomeration process of granular materials.