Dimensional analysis of a flow-by porous electrode and demonstration to all-vanadium redox flow batteries thereon. (1st December 2021)

• Record Type: Journal Article
• Authors: Pathak, Akanksha; Sharma, Ashwini Kumar; Gupta, Anoop Kumar
• Is Part Of: Journal of energy storage. Volume 44(2021)Part A
• Publication Date: 2021-12-01
• Subjects: Dimensional analysis -- Electrochemical flow system -- Buckingham's Pi theorem -- Vanadium redox flow battery (VRFB) -- Empirical correlation; Energy storage -- Periodicals; Energy storage -- Research -- Periodicals; 621.3126
• DOI: 10.1016/j.est.2021.103258
• Languages: English
• ISSNs: 2352-152X

Abstract

Abstract: Multiphysics multiscale electrochemical flow systems are challenging from the viewpoint of understanding their behavior and predicting their performance owing to their large number of design, material, and operational variables. Dimensional analysis offers a method for reducing such complex physical problems to the simplest form to facilitate a qualitative understanding of the system behavior along with quantitative description of the problem defined. This paper reports a dimensional analysis of a flow-by porous electrode, the main constituent of modern electrochemical flow systems. A step-by-step analysis is carried out starting with 15 primitive variables (including cell voltage as performance measure) and resulting in 7 dimensionless variables only to define the system. The paper goes beyond the reduction of number of variables. Physical significance of the identified dimensionless variables is deliberated to understand the role of underlying transport phenomena in the system, mainly in terms of irreversible losses. Further, the reliability of the dimensionless variables is established by performing scale modeling for an all-vanadium redox flow battery (VRFB) system via virtual experiments. Finally, a functional relationship, in the form of an empirical correlation among the dimensionless variables, is derived that can be utilized for predicting cell voltages of a VRFB system at specific conditions. Highlights: Dimensional analysis for a flow-by porous electrode is carried out. Relevant dimensionless numbers are derived using Buckingham's Pi theorem. Physical significance of dimensionless numbers is interpreted. Scale modeling is performed to establish the fidelity of dimensionless numbers. An empirical correlation is derived for system performance predictions.