Modelling the effects of oxygen evolution in the all-vanadium redox flow battery
Modelling the effects of oxygen evolution in the all-vanadium redox flow battery
The impact of oxygen evolution and bubble formation on the performance of an all-vanadium redox flow battery is investigated using a two-dimensional, non-isothermal model. The model is based on mass, charge, energy and momentum conservation, together with a kinetic model for the redox and gas-evolving reactions. The multi-phase mixture model is used to describe the transport of oxygen in the form of gas bubbles. Numerical simulations are compared to experimental data, demonstrating good agreement. Parametric studies are performed to investigate the effects of changes in the operating temperature, electrolyte flow rate and bubble diameter on the extent of oxygen evolution. Increasing the electrolyte flow rate is found to reduce the volume of the oxygen gas evolved in the positive electrode. A larger bubble diameter is demonstrated to increase the buoyancy force exerted on the bubbles, leading to a faster slip velocity and a lower gas volume fraction. Substantial changes are observed over the range of reported bubble diameters. Increasing the operating temperature was found to increase the gas volume as a result of the enhanced rate of O2 evolution. The charge efficiency of the cell drops markedly as a consequence.
bubble formation, flow battery, hydrogen evolution, mathematical model, numerical simulation
3192-3205
Al-Fetlawi, H.A.
8544fc8a-1c0c-4eb8-b828-fe71a4e9efb6
Shah, A.A.
5c43ac37-c4a7-4256-88ef-8c427886b924
Walsh, F.C.
309528e7-062e-439b-af40-9309bc91efb2
30 March 2010
Al-Fetlawi, H.A.
8544fc8a-1c0c-4eb8-b828-fe71a4e9efb6
Shah, A.A.
5c43ac37-c4a7-4256-88ef-8c427886b924
Walsh, F.C.
309528e7-062e-439b-af40-9309bc91efb2
Al-Fetlawi, H.A., Shah, A.A. and Walsh, F.C.
(2010)
Modelling the effects of oxygen evolution in the all-vanadium redox flow battery.
Electrochimica Acta, 55 (9), .
(doi:10.1016/j.electacta.2009.12.085).
Abstract
The impact of oxygen evolution and bubble formation on the performance of an all-vanadium redox flow battery is investigated using a two-dimensional, non-isothermal model. The model is based on mass, charge, energy and momentum conservation, together with a kinetic model for the redox and gas-evolving reactions. The multi-phase mixture model is used to describe the transport of oxygen in the form of gas bubbles. Numerical simulations are compared to experimental data, demonstrating good agreement. Parametric studies are performed to investigate the effects of changes in the operating temperature, electrolyte flow rate and bubble diameter on the extent of oxygen evolution. Increasing the electrolyte flow rate is found to reduce the volume of the oxygen gas evolved in the positive electrode. A larger bubble diameter is demonstrated to increase the buoyancy force exerted on the bubbles, leading to a faster slip velocity and a lower gas volume fraction. Substantial changes are observed over the range of reported bubble diameters. Increasing the operating temperature was found to increase the gas volume as a result of the enhanced rate of O2 evolution. The charge efficiency of the cell drops markedly as a consequence.
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Published date: 30 March 2010
Keywords:
bubble formation, flow battery, hydrogen evolution, mathematical model, numerical simulation
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Local EPrints ID: 69062
URI: http://eprints.soton.ac.uk/id/eprint/69062
ISSN: 0013-4686
PURE UUID: 7ade1ac4-0c7e-46bf-bd68-93f885728fd5
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Date deposited: 21 Oct 2009
Last modified: 13 Mar 2024 19:16
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Author:
H.A. Al-Fetlawi
Author:
A.A. Shah
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