Liquid-liquid flow in a corrugated channel: hydrodynamics and transfer

Abstract

International audienceMilli-structured heat exchanger/reactors are promising for theimplementation of chemical syntheses, especially rapid andexothermic ones. In the case of multiphase reactions, mass transfercan become the limiting step controlling the chemical reaction.Therefore, this work aims at characterizing the flow and the liquidliquid mass transfer in the millichannel of the "DeanHex"exchanger/reactor in order to build a complete model of this devicecapable of predicting its performances at an industrial scale.MethodsExperimental studies (hydrodynamics and mass transfer) areconducted in three zigzag millichannels of square cross-sections(hydraulic diameters d$_h$ = 2, 3 and 4 mm). Water/rhodamine B(RhB)/octanol fluid system is used. The flow is visualised fordifferent flowrates of the phases. The transfer of RhB from water tooctanol is then investigated for different total flowrates (1.5 to 6kg‧h-1) and flowrates ratios "q" (0.5 to 2). At the reactor outlet,based on the wettability of liquids to a given solid material, theorganic phase is extracted and analyzed by UV-Vis spectrometry.Results and discussionFour types of flow regimes are observed in the threemillichannels (Figure 1). A flow patterns map based on the Webernumber of the dispersed phase "Weaq" and the internal Dean numberof the continuous phase "Deiorg" is proposed, as shown in Figure