LOCAL MASS-TRANSFER FROM A CIRCULAR-CYLINDER IN A UNIFORM SHEAR-FLOW

Abstract

A naphthalene sublimation technique is used to investigate the rate of mass transfer from a circular cylinder in a turbulent uniform shear flow. The rate of shear and the mean flow Reynolds number are varied to study their effects on the mass transfer. It is found that the distribution of the local mass transfer rate on the circular cylinder is characterized by a shear parameter K(d), defined as S. d/ Uc) where S is the shear rate, d the cylinder diameter and U(c) the centreline mean velocity. The angular position at which the Sherwood number is minimum is approximately proportional to K(d) on both the upper and the lower surfaces of the cylinder. The overall mass transfer rate is largely independent of K(d) for the range of the present measurements 0 < K(d) < 0.132, but it is strongly dependent on the centreline mean Reynolds number.