Investigation of the influence of impact velocity and liquid bridge volume on the maximum liquid bridge length

Abstract

Several models exist to predict the capillary forces due to liquid bridges during static particle contacts. However, for dynamic impacts, there is still a lack of knowledge to accurately describe the geometry and rupture of liquid bridges. This is essential in order to calculate correctly the energy dissipation in numerical models. Therefore, the liquid bridge volume during the rebound phase of collision, the restitution coefficient, the rupture time and the maximum liquid bridge length were analyzed for a wide range of contact velocities from 0.0001to4.0 m∙s−1. To perform experiments at different velocities three experimental setups were developed. First, free-fall experiments with spherical particles colliding on a glass pane covered with a water layer were performed at different impact velocities from 0.3 to 1.5 m∙s−1 and water layer thicknesses. Secondly, a pneumatic setup was developed for investigating the maximum liquid bridge length at constant liquid bridge volume and contact velocities from 0.3 to 4.0 m∙s−1. A third setup was used to investigate the liquid bridge behavior during low velocities from 0.0001 to 0.04 m∙s−1. Based on the experimental results, a new model is presented to account for the significant influence of impact velocity on the maximum liquid bridge length.