Liquid–liquid two-phase mass transfer in T-type micromixers with different junctions and cylindrical pits

•Liquid-liquid extraction in T-type micromixers with novel shapes is investigated.•Water–Propionic acid–1-octanol was chosen for mass transfer analyzing.•Pits on junction and on the mixing channel were fabricated to enhance mixing.•Extraction efficiency increased up to 20%with collinear pits on mixing channel.•Extraction efficiency increased up to 30%with non-collinear pits on mixing channel.

This paper reports an experimental investigation of flow pattern and liquid–liquid two-phase mass transfer in different T-type micromixers with novel shapes. These micromixers were rectangular with a dimension of 0.5 mm width, 1 mm depth and 100 mm long. New configurations of T-micromixers were fabricated with change in their junction shapes and designing pits on the mixing channel to achieve the efficient mixing and mass transfer. Mixing and mass transfer in micro-mixers with one pit on T-junction and array of pits, in collinear and non-collinear orientation, on mixing channel was examined. Water–propionic acid–1-octanol was chosen for mass transfer analyzing. Results show that various type of two-phase flow pattern established at examined geometries. Results also depict that diameter of pit at the junction and designing of pit on mixing channel and its diameter has significant effect on mass transfer coefficient and extraction efficiency. The highest enhancement in the extraction efficiency of micromixer with pitted junction-non collinear channels was 28.7% compared with micromixer with Plain junction. In addition, extraction efficiencies in the micromixers with pitted mixing channel-collinear channels and pitted mixing channel-non collinear channels increased up to 55.7% and 78.7% compared with that of plain junction, respectively.

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