A Study of Liquid Bridge Dynamics: an Application to Micro-Assembly/Une Etude de la Dynamique du Pont Liquide: une Application au Micro-Assemblage

• Main Author: Valsamis, Jean-Baptiste
• Other Authors: Lambert, Pierre
• Format: Others
• Language: en
• Published: Universite Libre de Bruxelles 2010
• Subjects: Kelvin-Voigt model; weak formulation; Navier-Stokes; moving mesh; level set; finite element method; capillary forces; free surface; microfluidics; surface tension
• Online Access: http://theses.ulb.ac.be/ETD-db/collection/available/ULBetd-06142010-172042/

Micro-assembly processes suffer from some breaches due to the continuing trend towards an increase in the production capabilities as well as in the size reduction of the components manipulated. Usual manipulating schemes have reached their limit and capillary forces constitute a valuable alternative strategy. The goal of this work is to describe the dynamics of liquid bridges in the application of micro-assembly processes. The description is obtained using the Kelvin-Voigt model, with a spring, a damper, and a mass connected in parallel, supported by numerical simulations, analytical approximations and experiments. The works is divided into three parts. First we present important aspects of microfluidics, as well as the constitutive equations and an overview of numerical approaches used to describe fluid flow problems with moving interfaces. The second part is devoted to the capillary rise case, intended to validate and to compare the numerical approaches to analytical laws and experimental results. The implementation of the slipping and the dynamic contact angles is discussed. The last part focuses on the dynamics of the liquid bridge. The liquid bridge is confined between two circular and parallel plates and presents an axial symmetry. The description reveals that the stiffness depends on the surface tension and on the shape of the air/liquid interface, the damping coefficient depends on the viscosity and the volume of liquid and the equivalent mass depends on the density and the volume.