Influences of Silicabeads on the Venting of Weakly and Strongly Foaming Systems
Venting of systems containing solids has so far been treated as venting of two-phase systems and the presence of particles has been neglected. For nonfoaming systems, this has shown to be an appropriate assumption. To verify if this assumption is also valid for foaming systems, experiments were carried out regarding venting foaming systems without particles and in presence of silicabeads of varying sizes. Results show that particles influence the ventig behaviour. These results differ largely in respect to the degree of the foaminess of the system. Nevertheless recommendations for the design of pressure relief devices for foaming two-phase systems are with some limitations also applicable for three-phase systems.
A finite 3D element model coupled with a 2D finite volume one has been developed obatained in order to study the miscrostruture evolution during the desification of a green compact obtained by powder metturgy [1]. The simulation of the process was performed on to grains considering surface diffusion of the grains, grain boundary diffusion and volume diffusion in the grains, with as source terms the radii of curvature. The stress gradients are the driving forces of sintering. The mechanical behaviour of the grains is considered as elastic in the whole temperature range of the sintering cycle.