Convective Transport

Introduction

Convective transport (convective flow, bulk flow, convection) may refer to either heat or mass transfer. Convective transport takes place both by diffusion, i.e., the random Brownian motion of individual particles in the fluid, and by advection, in which matter or heat is transported by the larger-scale motion of currents in the fluid. Convective transport is used to refer to the sum of advection and diffusion (Bergman et al. 2011). Convective mass transfer cannot take place in solids, because neither bulk current flows nor significant diffusion can take place in solids, but it can take place in porous solids. Diffusion of heat can take place in solids and is referred to as heat conduction. In the context of membranes, convective flow refers to the transport of fluid (pure solvent or solution) across a porous membrane, which is driven by the applied pressure. Convective transport is the main mode of transport in microfiltration and ultrafiltration processes; it may also...