Effects of Gaseous Atmosphere and Container Composition on Tribo-charging of Packed Beds

Abstract

Granular packed beds have been extensively studied since the latter half of the 20th century, where theoretical models of random closest packing were verified through experimental procedure. These hard sphere models previously didn’t account for the effects of triboelectric charge, static electricity that accumulates on surfaces through repeated contact with other surfaces. This form of static charge can influence packing behavior of granular beds and can be affected by several factors such as bed material, granular size and atmospheric conditions. Previous research has utilized x-ray commuted tomography to analyze three-dimensional structures of packed beds, isolating factors such as granular size and humidity as areas of interest. This study aimed to explore other atmospheric conditions that could influenced packing behavior, by comparing the visual effects of inert or ambient gas on packing behavior of different granular bed systems. This study also aimed to understand how granular packing changes with granular material and column material. The results of our gaseous comparisons experiments leave the door open to continue research with a larger selection of sample conditions and gaseous environments. Additionally, comparisons between container material and bed material suggests tighter packing in systems where container material was conductively similar to its inner bed material.