Abstract
Microchannels are fundamental elements composing micro devices where chemical reactions and mass transfer are performed. As most of flows in microchannels are usually laminar, the liquids flow regularly. Therefore, mass transfer rate, chemical reaction rate and residence time are easily estimated for this flow. In this study, we examined the flow in a minichannel that fluids sequentially and alternately flow into the main channel through the opposite side branches. The flow regime is classified into a transition region and a full-developed one. When the side stream through the branch joins the main stream at the junction, the secondary flow occurs. Consequently, the interface contacting with the different stream is deformed, and then the concentration distribution is distorted. After the flow reaches the full-developed region, the concentration distribution remains in distortion. If this distortion is large, it becomes difficult to estimate for the mass transfer rate between two fluids or the chemical reaction at the contacting boundary between two fluid streams. In this study, the shape of contact interface has been measured experimentally, and the obtained data compared with the numerically simulated results. The flow pattern depends both on the flow rate ratio of two inlet flows and on Reynolds number of the stream after joining. The shape of contact interface at the full-developed region has been correlated with the function of the flow rate ratio and Reynolds number.
