Simulation of viscous sintering

The objective of this research is to develop reliable numerical methods to predict the deformation of an incompressible Newtonian viscous fluid region (Stokes Flow) driven by surface tension. In particular this mathematical model describes the physical processes that appear when a compact of glassy particles is heated to such a high temperature that the glass becomes a viscous creeping fluid. As a result, the particles are joining together so that the cohesion of the compact is increasing with time. This phenomenon is usually called viscous sintering and e.g. appears in the production of high-quality glasses. From the methods developed, theoretical insights can be obtained about the densification kinetics of such a compact. Therefore, a numerical simulation program is developed that calculates the deformation of a representative two-dimensional or an axisymmetric unit cell of the compact. A Boundary Element Method is applied to solve the involved integral equations of Stokes flow and the time integration is carried out by a variable step, variable order Backward Differences Formulae method.