To determine the amount of Mg turnings per cross section through the packed bed, the assumption was made that within a cross-section the magnesium turnings lie flat. From the known particle size distribution and the bed porosity, 474 and 154 turnings per cross section were calculated for the fine and coarse magnesium turnings, respectively. The flow path diameter and length vary between experiments due to the statistical nature of the poured magnesium bed and the varying geometries of the turnings, but according to Kraume , the determination of the hydraulic pore diameter is sufficient enough by assuming straight, parallel and uniform flow paths. The hydraulic pore diameter dh is used to specify the mean pore size and can be calculated by equation 7, with ε=void fraction and d32=Sauter diameter of magnesium turnings (fine turnings: d32=2.81 µm, coarse turnings: d32=5.48 µm).