Abstract
This paper reports a mass transfer model of a reactant flowing in a large aspect ratio microfluidic chip made of a channel with electrodes on the side walls. A semianalytical solution to the two-dimensional Fickian diffusion of a reactant in a microchannel, including the electrochemical reaction at the electrode interface and the velocity profile obtained from the Navier-Stokes equations in a fully developed laminar regime, is found. The solution is written in the Laplace domain in terms of transfer functions. The proposed solution is an extension of the Lévêque approximation describing the reactant diffusion from the electrode to the middle of the microfluidic channel. The main applications of this work are the use of the obtained transfer functions for the measurement of the Faradic current density or the chemical concentration at the electrode interface. The study can also be extended to the heat transfer in microfluidic electrochemical chips (temperature or heat flux measurements at the electrode interface).
Highlights
Published in PRE A PREPRINTA microfluidic electrochemical chip is made of a microchannel, with electrodes on opposite walls
The combination of the velocity profile and the mass diffusion has to be taken into account properly to describe the correct electrode mass transfer, or eventually the heat transfer as it is governed by similar physics and occurs simultaneously during any chemical reaction [7]
The mass transfer at the electrode interface in a microfluidic channel was studied in the case of a large width to height aspect ratio
Summary
A microfluidic electrochemical chip is made of a microchannel (width and height typically lower than a millimeter), with electrodes on opposite walls (either top and bottom or left and right). Considering a simplified but predictive averaged velocity profile in a large aspect ratio microfluidic channel, a semi-analytical solution in the Laplace domain is derived It is validated against a numerical model solving the complete problem and the Lévêque theory. The use of such a semi-analytical model would elucidate the mass transfer problem at the electrodes interface in regards to transfer functions of the current density and concentration field in the microchannel. Such formalism would pave the way toward improved energy conversion chips by enabling important performance characterization tools, such as through accurate measurements of the microchannel current density distribution.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
