Experimental Investigation on the Formation Mechanism of Liquid Bridges Between Wet Spherical Particles

Liquid bridge formation between wet granular governs a wide range of industrial processes. In experiments aimed at observing the volume and evolution of liquid bridges, the ability to form stable and uniform liquid films on particle surfaces is an essential prerequisite. However, existing experimental setups are incapable of maintaining such uniform coating, thereby precluding a complete characterization of the bridge evolution dynamics. To address this gap, a new experimental setup is developed in this work. Uniform liquid film coating on spherical particles is achieved for the first time. The formation process is captured by high-speed imaging, and the control variable method systematically quantifies the effects of liquid film thickness, distance between two particle surfaces, and particle radius ratio on the dimensionless liquid bridge volume. Quantitatively, increasing the dimensionless liquid film thickness by 0.01 raises the maximum dimensionless liquid bridge volume by 0.2; enlarging the dimensionless initial particle spacing from 0.067 to 0.133 and 0.200 reduces the maximum dimensionless liquid bridge volume by 3.0% and 4.9%, respectively; and a radius ratio of 6:4 lowers the maximum dimensionless liquid bridge volume by 10.9% compared to 6:6. The Reynolds number exhibits no discernible effect within the viscous-dominated regime investigated.