Topic
Microchannel
About: Microchannel is a research topic. Over the lifetime, 14178 publications have been published within this topic receiving 270770 citations.
Papers published on a yearly basis
Papers
More filters
••
TL;DR: A finite element model has been used in order to study the mixing process of species in a 100-microm-wide zigzag microchannel integrating a "Y" inlet junction, and the effects of both flow rate and channel geometry on hydrodynamics and mixing efficiency were illustrated.
Abstract: A finite element model has been used in order to study the mixing process of species in a 100-μm-wide zigzag microchannel integrating a “Y” inlet junction. The distribution of the concentration was obtained by solving successively the Navier−Stokes equation and the diffusion−convection equation in the steady state form. Because of the large range of Reynolds numbers studied (1 < Re < 800), the 2D diffusion−convection simulations are carried out with high diffusion coefficients. The results illustrated the effects of both flow rate and channel geometry on hydrodynamics and mixing efficiency. Below a critical Reynolds number of ∼80, the mixing is entirely ensured by molecular diffusion. For higher Reynolds numbers, simulations revealed the mixing contribution of laminar flow recirculations. This effect increases for lower values of diffusion coefficients. Experimental studies on the mixing of species at different flow rates are reported showing the same hydrodynamic tendency.
457 citations
••
TL;DR: In this paper, a packed-bed microchemical system consisting of a microfluidic distribution manifold, a microchannel array, and a 25-μm microfilter for immobilizing solid particulate material within the reactor chip and carrying out different heterogeneous chemistries is presented.
Abstract: A microchemical device has been built in silicon and glass by using microfabrication methods including deep-reactive-ion etch technology, photolithography, and multiple wafer bonding. The microchemical system consists of a microfluidic distribution manifold, a microchannel array, and a 25-μm microfilter for immobilizing solid particulate material within the reactor chip and carrying out different heterogeneous chemistries. Multiple reagent streams (specifically, gas and liquid streams) are mixed on-chip, and the fluid streams are brought into contact by a series of interleaved, high-aspect-ratio inlet channels. These inlet channels deliver the reactants continuously and cocurrently to 10 reactor chambers containing standard catalytic particles. The performance of the microfabricated “packed-bed” reactor is compared to that of traditional multiphase packed-bed reactors in terms of fluid flow regimes, pressure drop, and mass transfer. The hydrogenation of cyclohexene is used as a model reaction to measure t...
445 citations
••
TL;DR: The device was used to detect the separation of a mixture of proteins and small molecules by capillary electrophoresis; the separation illustrated the suitability of this integrated fluorescence detection system for bioanalytical applications.
Abstract: This paper describes a prototype of an integrated fluorescence detection system that uses a microavalanche photodiode (μAPD) as the photodetector for microfluidic devices fabricated in poly(dimethylsiloxane) (PDMS). The prototype device consisted of a reusable detection system and a disposable microfluidic system that was fabricated using rapid prototyping. The first step of the procedure was the fabrication of microfluidic channels in PDMS and the encapsulation of a multimode optical fiber (100-μm core diameter) in the PDMS; the tip of the fiber was placed next to the side wall of one of the channels. The optical fiber was used to couple light into the microchannel for the excitation of fluorescent analytes. The photodetector, a prototype solid-state μAPD array, was embedded in a thick slab (1 cm) of PDMS. A thin (80 μm) colored polycarbonate filter was placed on the top of the embedded μAPD to absorb scattered excitation light before it reached the detector. The μAPD was placed below the microchannel an...
440 citations
••
TL;DR: In this article, the cooling performance of a microchannel heat sink with nanoparticle-fluid suspensions (nanofluids) is numerically investigated by using a theoretical model of thermal conductivity of nanofluid that accounts for the fundamental role of Brownian motion.
431 citations
••
TL;DR: An integrated microfluidic system that achieves efficient mixing between two miscible liquid streams by introducing a gas phase, forming a segmented gas-liquid (slug) flow, and completely separating the mixed liquid and gas streams in a planar capillary separator is presented.
Abstract: We present an integrated microfluidic system that achieves efficient mixing between two miscible liquid streams by introducing a gas phase, forming a segmented gas-liquid (slug) flow, and completely separating the mixed liquid and gas streams in a planar capillary separator. The recirculation motion associated with segmented flow enhances advection in straight microchannels without requiring additional fabrication steps. Instantaneous velocity fields are quantified by microscopic particle image velocimetry (muPIV). Velocities in the direction normal to the channel amount to approximately 30% of the bulk liquid velocity inside a liquid segment. This value depends only weakly on the length of a liquid segment. Spatial concentration fields and the extent of mixing (EOM) are obtained from pulsed-laser fluorescence microscopy and confocal scanning microscopy measurements. The mixing length is reduced 2-3-fold in comparison with previously reported chaotic micromixers that use three-dimensional microchannel networks or patterned walls. Segmented gas-liquid microflows allow mixing times to be varied over several orders of magnitude between milliseconds and second time scales.
430 citations