title: Pore-Scale Modeling of Non-Newtonian Shear-Thinning Fluids in Blood Oxygenator Design.
abstract: This paper reviews and further develops pore-scale computational flow modeling techniques used for creeping flow through orthotropic fiber bundles used in blood oxygenators. Porous model significantly reduces geometrical complexity by taking a homogenization approach to model the fiber bundles. This significantly simplifies meshing and can avoid large time-consuming simulations. Analytical relationships between permeability and porosity exist for Newtonian flow through regular arrangements of fibers and are commonly used in macroscale porous models by introducing a Darcy viscous term in the flow momentum equations. To this extent, verification of analytical Newtonian permeability-porosity relationships has been conducted for parallel and transverse flow through square and staggered arrangements of fibers. Similar procedures are then used to determine the permeability-porosity relationship for non-Newtonian blood. The results demonstrate that modeling non-Newtonian shear-thinning fluids in porous media can be performed via a generalized Darcy equation with a porous medium viscosity decomposed into a constant term and a directional expression through least squares fitting. This concept is then investigated for various non-Newtonian blood viscosity models. The proposed methodology is conducted with two different porous model approaches, homogeneous and heterogeneous, and validated against a high-fidelity model. The results of the heterogeneous porous model approach yield improved pressure and velocity distribution which highlights the importance of wall effects.
authors.forename: Kenny W Q
authors.initials: KW
authors.lastname: Low
authors.forename: Raoul
authors.initials: R
authors.lastname: van Loon
authors.forename: Samuel A
authors.initials: SA
authors.lastname: Rolland
authors.forename: Johann
authors.initials: J
authors.lastname: Sienz
mesh_terms: D001696:Biomechanical Phenomena; D001809:Blood Viscosity; D004867:Equipment Design; D018056:Hemorheology; D008954:Models, Biological; D016011:Normal Distribution; D010106:Oxygenators; D010539:Permeability; D016062:Porosity; D033081:Shear Strength