Calculating tortuosity in quasi-random anisotropic packings

SUMMARY: Relating the micro-structural characteristics ofporous media to their through-flow properties remains an inter-esting challenge for the paper coating community. The researchpresented herein attempts to address this challenge throughcomputational science for complex quasi-random anisotropicplate-like particle packings. In plate-like packings comprisingmonodisperse plates of equal aspect ratios, tortuosity is seen todecrease as a function of porosity. However, tortuosity is con-currently found to increase as a function of increasing particleaspect ratio, even though the porosities of such packings arehigher. Dimensional and rotational characteristics of plate-likepackings are therefore seen to be more influential to tortuositythan volume fractions of pore space. When comparing tortuosi-ty to mean tracer velocities, the generic trend is one of inverseproportionality, with higher levels of scatter existing at lowertracer velocities. It is postulated that nesting sites within theparticle microstructure accounts for the lower velocities byeffectively trapping the flow of fluid for discrete time periods,and reducing the total distances travelled through the packing.As a function of the mean spatial rotations, tortuosity is taken tobe 2