Periodic open cellular structures with ideal cubic cell geometry: Effect of porosity and cell orientation on pressure drop behavior

Periodic open cellular structures (POCS) with ideal cubic cell geometry (icPOCS) were manufactured via the selective electron beam melting technique (SEBM). Depending on the cell dimensions (cell length, strut diameter) and cell orientation in respect to the main axis of the cylindrical structures, the icPOCS investigated in this work exhibit different porosities and/or tortuosities. The structures were characterized with respect to their morphological and geometrical parameters such as strut and cell dimension, specific surface area, and porosity using different techniques (e.g., micro-computed tomography and helium pycnometry). Additionally, a model for the calculation of the specific surface area is presented which takes surface roughness into account. The model enables the determination of the specific surface area on the basis of only two geometrical parameters, i.e., the strut diameter and the cell length, which are both easy to determine for such highly regular open cellular structures. The pressure drop of the icPOCS was measured with air as working fluid. A correlation allowing for the prediction of the pressure drop of icPOCS was developed based on the Ergun equation in its basic form. The presented correlation reflects the porosity and cell orientation and is solely based on the geometric properties of the structures. As the correlation does not rely on the use of empirical fitting parameters it is fully predictive. (C) 2014 Elsevier B.V. All rights reserved.