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.