1 On the prediction of an average droplet size evolution during transport in homogeneous porous media under laminar flow conditions Frank A. Coutelieris Department of Engineering and Management of Energy Resources, University of Western Macedonia, Bakola & Sialvera, 50100 Kozani, Greece , Tel: +302461056751; Fax: +302461021731; e0mail: fcoutelieris@uowm.gr and National Center for Scientific Research “Demokritos”, 15310 Aghia Paraskevi Attikis, Greece Multiphase transport, Sγ moment, breakup, coalescence, porous media. This paper deals with the prediction of a spatially averaged droplet size during transport within homogeneous porous media. More precisely, this transport process occurs in a mixture of a continuous aqueous phase which includes a discontinuous one in the form of droplets. The mixture flows in a homogeneous porous medium under laminar flow conditions. The collection of γorder moments, Sγ, is used here to describe the time evolution of the spatially averaged mean diameter of spherical droplets, mainly because Sγ satisfies the convective/diffusive transient transport equation. As it is well known, breakup and coalescence are the primary local phenomena controlling the size