High Schmidt mass transfer in a laminar impinging slot jet flow

In this paper, high Schmidt-number mass transfer to a line electrode in laminar impinging slot-jet flows is investigated experimentally and numerically. Slot-based Reynolds numbers from 220 to 690 are considered. The mass-transfer measurements, made by the electrochemical method on 100 mu m electrodes, are compared to the computed wall shear via an established analytical relationship. The local shear is obtained from steady, twodimensional flow-field simulations of the Navier-Stokes equations. The use of an isolated line electrode and a small electrode size (100 mu m) makes it possible to resolve the sharp variations in shear and mass transfer in the stagnation region. Both the experimental and theoretical results show that the peak values in Nusselt number occur at a point one-half to one jet width away from the stagnation point. Earlier experimental studies of heat transfer (Prandtl number of 0.72) reported by Garden and Akfirat [R. Garden, J.C. Akfirat, Heat transfer characteristics of impinging two-dimensional air jets, ASME Journal of heat Transfer 101 (1966) 101-108] (referred to in the figures as GA66) and mass transfer by Alkire and Ju [R., Alkire, J. Ju, High speed selective electroplating with impinging two-dimensional slot jet flow, J. Electrochemical Society 134 (2) (1987) 294-299] (referred to in the figures as AJ87) were not able to observe this behavior near the stagnation point. (C) 2000 Elsevier Science Ltd. All rights reserved.