Modeling of Transport Phenomena in Metal Foaming

ude gas voids in the material structure with the real possibility to modify ad hoc their physical properties. During the foaming process of a metal, simultaneous mass, momentum and energy transport mechanisms arise. In this work we propose a model considering mass transfer phenomena coupled to the growth and motion of a gas bubble in the liquid metal. The diffusion of the gas in the liquid is studied by applying the Fick's law and convective transport. The equilibrium concentration at the gas-liquid interface is modeled by the Sievert's law with surface tension effects included. The numerical results of the simulation show that the computational model, using the phase field method for capturing the phase interface, can be effective. The computations simulate satisfactorily mass transfer, bubble expansion, interface movement and fluid flow. In this way other physical mechanisms of foaming could be included in a future more comprehensive model

Multiphysics Modeling of a Metal Foam

In metal foam processing nucleated gas bubbles expand in a heated metal, then the foam cools and solidifies. In this work we use Comsol Multiphysics 4.2 to study heat transfer, growth and movement of hydrogen gas bubbles in liquid aluminium for a metal foam expanding in a 2D mold. In the model, the bubble growth is simulated by using a specific expansion rate, then the movement of hydrogen gas bubbles in liquid aluminium is numerically computed by using the equations of fluid dynamics coupled to the level set method. In spite of the problem complexity and the needed simplifications, the computational model is very well suited to describe satisfactorily heat transfer, bubble expansion, interface movement and fluid flow during the foaming process. Interesting considerations can be drawn regarding the temperature field in the system, the influence of the mold geometry and the resulting expansion of the metal foam