Assessment of VOF Strategies for the Analysis of Marangoni Migration, Collisional Coagulation of Droplets and Thermal Wake Effects in Metal Alloys Under Microgravity Conditions

摘要

A possible approach for the investigation of a number of aspects related to the processing of immiscible alloys, made possible by recent progress in both fields of moving boundary (VOF) methods and speed of computers, is discussed. It can capture in a single numerical treatment and without limiting assumptions both macroscopic information (i.e. the macrophysical problem, heretofore treated in terms of population dynamics) and microscopic details (i.e. the microphysical problem, heretofore treated within the framework of boundary integral methods and/or under the assumption of non-deformable drops). The role played by coalescence in changing the Marangoni migration velocity is discussed together with the possible influence of thermal wake effects for small and large values of the Prandtl number. Some prototype preliminary (very heavy) simulations are used for a better representation of some still unexplored or overlooked aspects.