(430d) Computational Fluid Dynamics Simulation of Hydrodynamics in a Rotating Cylinder Electrode Reactor: Understanding Mass Transport Effects in Electrocatalysis

Due to the increasing profitability of renewable energy sources, electrochemical systems to replace fossil-fuel based processes are gaining momentum towards industrial applications. These processes often involve complex interactions between mass, charge and heat transport as well as reaction kinetics. To effectively scale these electrochemical processes to industrial applications, these phenomena must be decoupled to enable intelligent design of production scale reactors. The rotating cylinder electrode (RCE) reactor is particularly suited to this task due to the high degree of symmetry allowing well defined hydrodynamic conditions. Computational Fluid Dynamics (CFD) studies have previously been used to investigate the bulk flow in this type of reactor. However, these studies often overlook the Importance of flow conditions in the boundary region near the surface of the rotating cylinder, especially regarding mass transport to the surface during reaction under turbulent flow conditions.

In this study, CFD modeling using Ansys Fluent software is used to elucidate the hydrodynamics in a gas tight RCE reactor at rotation speeds between zero and 800 rpm while under conditions of mass transport limited current. Experimental results for mass transfer limited ferricyanide reduction are used to evaluate the validity of the simulation. Details and justifications for assumptions and simulation methods used in this study are presented to provide a detailed understanding of the effect that each has on the ability to accurately simulate RCE systems where mass transport plays a critical role. The results of this study provide a methodical approach to simulating the hydrodynamics of an RCE reactor that is verified by experimental data. This simulation methodology can be utilized as the foundation for simulation of any mass transport dependent electrochemical reaction in an RCE, such as aqueous CO­₂ Reduction.