Direct Simulation of Transport in Open-Cell Metal Foams

Flows in porous media may be modeled using either a macroscopic approach, where volume-averaged semi-empirical equations are used to describe flow characteristics, or a microscopic approach, where small-scale flow details are simulated by considering the specific geometry of the porous medium. A direct simulation of the transport in an open-cell metal foam is carried out in the present study using a periodic unit cell. The foam geometry is created by assuming the pore to be spherical. The spheres are located at the vertices and at the center of the unit cell. The periodic foam geometry is obtained by subtracting the unit cell cube from the spheres. Fluid and heat flow are computed in the periodic unit cell. The objective of the present study is to obtain the effective thermal conductivity, pressure drop and local heat transfer coefficient from a consistent direct simulation of the open-cell foam structure. The computed values compare well with the existing experimental measurements and semi-empirical models. The results and the merits of the present approach are discussed.