Numerical simulation of the movement of microparticles

Abstract

The work aims at the numerical investigation of the dynamics of microparticles. Microparticles are considered to be ultrafine particles and similar size liquid droplets. Looking form mechanics point of view, it is important to understand the interaction behaviour of different states of matter. The improved understanding and the ability to numerically model them may help to better understand flow processes involving both in science and industry. In order to understand the behaviour of microparticles as a system, it is important to understand the behaviour of a single microparticle, as a component. The particle considered in the investigation is a microparticle, which can deform and stick during its motion and interaction. Also, it is important to understand droplet behaviour, when during interaction with the surface the droplet loses its shape. The aim of this project is the investigation of the microparticle dynamics by applying the discrete element method (DEM) as well as droplet dynamics by using COMSOL software. With the DEM the microparticle motion is described in the context of a Lagrangian framework influenced by nonlinear interaction forces. Based on DEM simulations microparticle interaction models will be applied, which allow a description of the general characteristics of the particle behaviour, such as coefficient of restitution for an elastic and elastic-plastic solid particle. Thereby the assumption is made that the microparticle behaviour during its impact is governed by mechanical deformation processes. Interaction models will be applied for the simulation of the motion of the liquid droplet, when initial interaction velocity with the surface is similar as that of the solid particle. Looking from the modelling point of view, the microparticle behaviour can be described throughout the motion towards a surface, interaction at a distance and interaction when the microparticle has made contact.