Interface configuration of the two layered laminar flow in a curved microchannel

Three-dimensional direct observation of fluid dynamics in microchannels was performed by confocal fluorescence microscopy and three-dimensional computational fluid dynamics simulation to examine the fluid interface in curved microchannels. Results revealed that the interface of the two laminar flows is heavily distorted and increases the interfacial area because of its curved structure. The combined effect of flow velocity, curvature radius of the microchannel, density, and viscosity on the interface configuration was simulated. Increasing flow velocity and density complicated the interface configuration more. In contrast, increasing curvature radius and viscosity simplified it. Interface distortion is emphasized in a microchannel whose depth is five times its width. The interface configuration is important because it affects diffusion and chemical reactions that occur at the interface. Results herein emphasize the importance of microchannel design based on a three-dimensional comprehension of fluids and their associated mixing behavior. (C) 2004 Elsevier B.V. All rights reserved.