Finite Element Method in Electrochemistry
The group has a broad range of experience in the development of numerical techniques for application in the field of microreactors and electrochemistry.
One popular method we use is the Finite Element Method (FEM) to calculate, concentration distributions, fluid velocities, temperature variations and
potential distribution within these environments. These codes allow the design and optimisation of small devices to be performed on PC level computers.
In a typical simulation we may wish to understand the fluid velocity within a microduct. Solution of the appropriate form of the Navier-Stokes
equations subject to certain boundary conditions allows the prediction of fluid dynamics within the structrually well defined reactors (see below).
Solution of the relevant equations proceeds by dividing the simulation volume into a series of elements, this can be carried out manually or by the use of
suitable automatic mesh generation routines. The figure below shows a coarse three dimensional element grid used for the simulation of fluid flow within
a 'T' cell
where two streams converge to a single outlet area.
Schematic of a finite element grid used to model the convergence of two flowing reactant streams into a single region
The codes provide the capability of visualising the reagent concentrations, solution velocities and temperature distributions within the
reactors. Below are some images obtained from the simulations, first the solution velocities within two different microcell geometries:
Fluid velocity profiles within two rectangular ducts of different height:width ratios
and second a cross section through a rectangular duct where an electrolysis reaction is driven on the bottom wall of a microreactor, where a microband
electrode is embedded. In this simulation a solution containing an electroactive agent is pumped through the cell and the reagent is destroyed at the
electrode surface ay a mass transport limited rate. The simulations show how the reagent is depleted for this specific flow rate throughout the
reactor.
Concentration distribution within a microreactor
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