Impact of fluid dynamic characteristics near the surface of the anode electrode on the performance of recirculation-type microbial fuel cells using computational fluid dynamics

Abstract

This study examines how fluid dynamic properties near the anode electrode surface (carbon cloth and carbon paper) affect the operation of recirculation-type microbial fuel cells (MFCs) at different flow rates (140, 240, and 340 mL/min) using computational fluid dynamics (CFD). The contribution of this research clarifies how changes in velocity, pressure, and shear stress influence substrate distribution and biofilm formation in the anode by modeling intricate flow patterns and mass transport phenomena at the fluid-anode microscale interface. Aside from the use of CFD simulation, the experiment was carried out by means of particle image velocimetry application accessed in the MATLAB software for the actual flow field visualization and electrochemical measurements for the voltage, current density, power density and impedance. From the statistical analysis using ANOVA, results showed that there is a significant difference in the mean power densities from flowrate + anode electrode combinations (140CC, 140 CP, 240 CC, 240 CP, 340 CC and 340 CP) and this was further confirmed using the Tukey's pairwise comparison post hoc analysis showing 140CP indeed has the highest power density at 297.60 mW/m² with a corresponding predicted boundary layer thickness from CFD at 15.7 mm.