Critical revision and extension of permeability models for packed granular media under laminar flow regime

The aim of this thesis study is to investigate the behavior of packed beds in granular media that are crossed by fluid phase. In particular, packed beds’ permeability is derived from experimental tests employing air under viscous and laminar flow regime. Several materials different in sizes, shape and distributions are tested. Established literature models with sound theoretical base are critically revised and extended to increase their predictive capability. Especially, Panda and Lake (1994) and Ruth and Ma (1992) models- as reformulation of the early Kozeny Carman equation- are considered. The first proposes an entire statistical approach based on particle size distribution to define packed beds characteristic lengths; the latter suggests an effective permeability dependence on fluid velocity firmly, creating a unique nevertheless interesting case. Both the models are investigated, highlighting strengths, limitations and development opportunities. At the end, they’re modified with new physical considerations. A new model is introduced with the aim to correct for the effective resistance contributions along packed beds. This requires porous media knowledge at microscopic scale, with clear distinction between pore bodies and throats. The former are responsible of fluid conductance while the others of fluid resistance. By applying viscous dissipation equation at local scale a new family of equivalent diameter is deduced, which results in a throats-based model. This is obtained by weighting the number of pores and throats encountered by a fluid streamline along its path. Finally, permeability prediction with respect to classical models is improved.