Wet granular flow control through liquid induced cohesion

TL;DR

This study investigates how liquid-induced cohesion affects wet granular flow, introducing a cohesion-scaling approach that maintains consistent flow behavior across different particle sizes in rotating drums.

Contribution

The paper presents a new cohesion-scaling methodology that enables invariant flow characteristics in wet granular materials with varying particle sizes.

Findings

Liquid cohesion reduces the flowing region width and surface particle velocity.

Cohesion increases the creeping region width and the dynamic angle of repose.

Granular temperature decreases with increased capillary forces.

Abstract

Liquid has a significant effect on the flow of wet granular assemblies. We explore the effects of liquid induced cohesion on the flow characteristics of wet granular materials. We propose a cohesion-scaling approach that enables invariant flow characteristics for different particles sizes in rotating drums. The strength of capillary forces between the particles is significantly reduced by making the glass beads hydrophobic via chemical silanization. Main results of rotating drum experiments are that liquid-induced cohesion decreases both the width of the flowing region and the velocity of the particles at the free surface, but increases the width of the creeping region as well as the dynamic angle of repose. Also, the local granular temperature in the flowing region decreases with an increase of the capillary force. The scaling methodology in the flow regimes considered (rolling and cascading regimes) yields invariant bed flow characteristics for different particle sizes.