Author’s version Published in Transport in Porous Media 96(1), pp 1-20 DOI: 10.1007/s11242-012-0070-5 http://dx.doi.org/10.1007/s11242-012-0070-5 Extension of the Darcy-Forchheimer law for shear thinning fluids and validation via pore- scale flow simulations Tiziana Tosco 1 , Daniele L. Marchisio 2 , Federica Lince 2 , Rajandrea Sethi 1(*) 1 DIATI – Dipartimento di Ingegneria dell’Ambiente, del Territorio e delle Infrastrutture – Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino, Italy 2 DISAT – Dipartimento Scienza Applicata e Tecnologia – Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino, Italy Phone +390110907735 Fax +390110907699 Email: rajandrea.sethi@polito.it ABSTRACT: Flow of non-Newtonian fluids through porous media at high Reynolds numbers is often encountered in chemical, pharmaceutical and food as well as petroleum and groundwater engineering and in many other industrial applications. Under the majority of operating conditions typically explored, the dependence of pressure drops on flow rate is non-linear and the development of models capable of describing accurately this dependence, in conjunction with non trivial rheological behaviours, is of paramount importance. In this work pore-scale single-phase flow simulations conducted on synthetic two-dimensional porous media are performed via computational fluid dynamics for both Newtonian and non-Newtonian fluids, and the results are used for the extension and validation of the Darcy-Forchheimer law, herein proposed for shear thinning fluid models of Cross, Ellis and Carreau. The inertial parameter β is demonstrated to be independent of the viscous properties of the fluids. The results of flow simulations show the superposition of two contributions to pressure drops: one, strictly related to the non-Newtonian properties of the fluid, dominates at low Reynolds numbers, while a quadratic one, arising at higher Reynolds numbers, is dependent on the porous medium properties. The use of pore-scale flow simulations on limited portions of the porous medium is here proposed for the determination of the macroscale averaged parameters (permeability K, inertial coefficient β and shift factor α), which are required for the estimation of pressure drops via the extended Darcy-Forchheimer law. The method can be applied for those fluids which would lead to critical conditions (high pressures for low permeability media and/or high flow rates) in laboratory tests. KEYWORDS: Darcy-Forchheimer law; shear thinning fluid; Computational Fluid Dynamics; pore-scale simulations; non-Newtonian flow. 1