Electrochemical Mass Transfer to Parallel Plates With and Without Turbulence Promoters: Simulation of Plate Heat Exchanger Configurations

摘要

The electrochemical diffusion limited current technique (DLCT) was used to model constant wall temperature heat transfer to parallel plates. The method is suitable for measuring local transfer rates which reveal the flow structure close to the wall. By analogy the mass transfer results are applicable to transfer as well. Average mass transfer rates were measured with fully as well as partially active electrodes in a rectangular duct of low aspect ratio. Mass transfer in the turbulent range suggests a square root dependence of Stanton on the friction factor. This contrasts with the linear dependence predicted by the Chilton-Colburn analogy. An idealized model based on this assumption and making use of results obtained for turbulent transfer to a flat plate in an infinite medium predicts a relationship in approximate agreement with the experimental correlation given above. The experimental results for fully turbulent flow also correlate well according to the mass transfer similarity law indicating that the mass transfer coefficient is determined by the hydrodynamic situation prevailing at the wall.