LAUSR

Mass transfer around a slender drop in a simple shear and creeping flow, at zero Peclet numbers (Pe = 0), is the subject of this theoretical report. The problem is governed by two dimensionless parameters: The capillary number (Ca >> 1) and the viscosity ratio (λ << 1). The fluid mechanics model of Hinch and Acrivos predicts an S-shaped drop with pointed ends that is almost parallel with the direction of the flow. Making use of the analogy between electrostatics and diffusion (Pe = 0), both governed by the Laplace equation, together with the work of Szego on the capacity of a condenser, a simple model is suggested by assuming the drop to be a slender prolate spheroid with rounded ends. The results suggest the following: (a) as the capillary number increases, the drop becomes thinner and longer and its surface area increases, leading to larger mass transfer rates; and (b) for the same capillary number, extensional flow is much more effective than simple shear flow in mass transfer operations. This article is protected by copyright. All rights reserved