Flow visualisation: a voltammetric approach

A novel approach to the visualisation and quantification of mass transfer i n liquid flow is presented. The technique utilises an array of microstrip e lectrodes sited within a duct through which the electrolyte solution is pum ped. The electrolyte solution contains a reagent that may be oxidised and i n the process undergo a colour change. The electrolysis products are then s wept through the cell and the pathway imaged via a digital video. Results a re presented for an experimental geometry where a rectangular obstruction i s deliberately introduced into the duct. Transport rates within the cell ar e restricted such that Stokes flow conditions are maintained throughout and the streamlines generated from the electrolysis used to map the flow profi les through the devices. The merits of the approach are discussed and the p otential of numerical modelling to provide quantitative analysis are highli ghted. (C) 2001 Elsevier Science B.V. All rights reserved.