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Consistent non-equilibrium thermodynamic modeling of hydrogen fuel cells
Thesis title in Czech: Konzistentní modelování vodíkových palivových článků pomocí nerovnovážné termodynamiky
Thesis title in English: Consistent non-equilibrium thermodynamic modeling of hydrogen fuel cells
Key words: Non-equilibrium thermodynamics|fuel cells|numerics
English key words: Nerovnovážná termodynamika|palivové články|numerika
Academic year of topic announcement: 2020/2021
Thesis type: diploma thesis
Thesis language: angličtina
Department: Mathematical Institute of Charles University (32-MUUK)
Supervisor: doc. RNDr. Michal Pavelka, Ph.D.
Author: hidden - assigned and confirmed by the Study Dept.
Date of registration: 28.03.2021
Date of assignment: 13.04.2021
Confirmed by Study dept. on: 25.05.2021
Date and time of defence: 15.06.2022 09:00
Date of electronic submission:03.05.2022
Date of submission of printed version:03.05.2022
Date of proceeded defence: 15.06.2022
Opponents: doc. RNDr. Ondřej Souček, Ph.D.
 
 
 
Advisors: Mgr. Ondřej Kincl, Ph.D.
Guidelines
1) Review of classical irreversible thermodynamics
2) Formulation of equations for a stirred-tank-reactor stationary hydrogen fuel cell
3) Numerical analysis of a 1D fuel cell with hydrogen on both sides
4) Analysis of the relation between the apparent drag coefficient and boundary conditions (e.g. applied potential)
5) If possible, an answer will be provided to the question of why the proton current and water flux cease to be linearly correlated for higher applied voltages.
References
[1] Benziger, J. B., Cheah, M. J., Klika, V. and Pavelka, M., Interfacial constraints on water and proton transport across Nafion membranes, J. Polym. Sci. Part B, July 2015
[2] Pavelka, M., Thermodynamic analysis of processes in Hydrogen fuel cells, Ph. D. dissertation, Charles University, 2015.
Preliminary scope of work in English
Water and proton fluxes across a Nafion based membrane electrode assembly can be expressed as functions of the applied electric potential while controlling water activity an temperature. For sufficiently small applied electrical potential differences, water and proton fluxes are correlated, and the ratio of water flux to proton flux, the drag coefficient, is constant and independent of the applied electrical potential, water activity and temperature. [1,2]

For larger applied electric potential differences, water and proton fluxes are no longer linearly correlated; the proton flux saturates with increasing electrical potential while the water flux increases with applied electric potential. Why?
 
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