Meshing of porous foam structures on the micro-scale

A semi-automatic block-structured grid generation technique for hexahedral meshing of porous open cell Kelvin foam structures for investigation of the pore scale fluid flow is presented. The performance of the algorithm is compared with a tetrahedral full automatic Delaunay meshing technique. In the first part of the paper the meshing strategies are explained. In the second part grid generation times, simulation times and the mesh quality are evaluated. For this Computational Fluid Dynamics (CFD) simulations for both a diffusion-dominated case (Re = 0.129) and a convection-dominated case (Re = 129) are carried out and analysed on four different cell resolutions of each mesh type. For the quality evaluation three different a posteriori error estimates are studied for the two mesh types on the different mesh sizes. The results are: the block-structured grid generation technique is about 10–20 times faster than the tetrahedral full automatic technique. While the mean field error estimates are comparable for both meshes, the maximum field error estimates for the block-structured meshes are only half of those for the tetrahedral meshes. Reaching simulation results of the same quality the hexahedral mesh needs about 20–40% less iterations with comparable mesh sizes. The time per iteration for the hexahedral meshes are up to 94% smaller than for the tetrahedral meshes. This makes the semi-automatic block-structured grid generation technique especially suitable for parameter studies and for the investigation of micro-scale flows in foam structures consisting of large quantities of Kelvin cells.