Publica
Hier finden Sie wissenschaftliche Publikationen aus den FraunhoferInstituten. On laminar flow of nonnewtonian fluids in porous media
 Transport in porous media : TIPM 111 (2016), No.1, pp.253264 ISSN: 01693913 ISSN: 15731634 

 English 
 Journal Article 
 Fraunhofer ITWM () 
 nonNewtonian flow; porous media 
Abstract
Flow of generalized Newtonian fluids in porous media can be modeled as a bundle of capillary tubes or a porescale network. In general, both approaches rely on the solution of Hagen–Poiseuille equation using power law to estimate the variations in the fluid viscosity due to the applied shear rate. Despite the effectiveness and simplicity, power law tends to provide unrealistic values for the effective viscosity especially in the limits of zero and infinite shear rates. Here, instead of using power law, Carreau model (bubbles, drops, and particles in nonNewtonian fluids. Taylor & Francis Group, New York, 2007) is used to determine the effective viscosity as a function of the shear strain rate. Carreau model can predict accurately the variation in the viscosity at all shear rates and provide more accurate solution for the flow physics in a single pore. Using the results for a single pore, normalized Fanning friction coefficient has been calculated and plotted as a function of the newly defined Reynolds number based on pressure gradient. For laminar flow, the variation in the friction coefficient with Reynolds number has been plotted and scaled. It is observed that generalized Newtonian fluid flows show Newtonian nature up to a certain Reynolds number. At high Reynolds number, deviation from the Newtonian behavior is observed. The main contribution of this paper is to present a closedform solution for the flow in a single pore using Carreau model, which allows for fast evaluation of the relationship between flux and pressure gradient in an arbitrary pore diameter. In this way, we believe that our development will open the perspectives for using Carreau models in porenetwork simulations at low computational costs to obtain more accurate prediction for generalized Newtonian fluid flows in porous media.