Flow of magnetorheological fluid through porous media

Flow of a magneto-rheological (MR) fluid through different types of porous media (bundle of cylinders, packed beds of magnetic and non-magnetic spheres and cylinders) is considered, both theoretically and experimentally. The theory is based on averaging the magnetic and rheological properties of MR fluid in tortuous channels making different angles between local field and local velocity. A comparison of the pressure drop through porous beds and spiral channels is analyzed and practical recommendations are developed. It is shown that the mean yield stress of Bingham MR fluid (as well as the pressure drop, DeltaP) depends on the mutual orientation of the external magnetic field and the main axis of the flow. This theory is tested against our experimental results and is shown to well predict the pressure drop obtained in different porous media. (C) 2003 Editions scientifiques et medicales Elsevier SAS. All rights reserved.