A numerical study of the gas-liquid, two-phase flow maldistribution in the anode of a high pressure PEM water electrolysis cell

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Abstract

In this work, the use of a circular-planar, interdigitated flow field for the anode of a high pressure proton exchange membrane (PEM) water electrolysis cell is investigated in a numerical study. While PEM fuel cells have separated flow fields for reactant transport and coolant, it is possible to operate a PEM electrolysis cell with the anode flow field serving as both. This allows for a simpler system and a thinner design, however sets new and more strict requirements for the flow field to distribute uniformly. For the present study, two computational fluid dynamics models are developed; a single-phase flow model for establishing the effect of geometry and a two-phase flow model for studying the effect of dispersed gas bubbles. Both models account for turbulence and heat transport. By means of the developed models, it is elucidated that the circular-planar shape of the interdigitated flow field causes maldistribution, if land areas of equal width are applied. Moreover, below a water stoichiometry of 350, and at a current density of 1 A/cm2, flow and temperature maldistribution is adversely affected by the presence of the gas phase; particularly gas hold-up near outlet channels can cause excessive formation of hotspots. As the water stoichiometry increases, the flow maldistribution increases as well. Nonetheless, its impact on the temperature distribution is counterbalanced by an overall increase in heat capacity of the flow. Hence, a relative uniform temperature distribution is achieved at and above nominal flow conditions. In a parametric investigation it is further underlined that the predicted formation of hotspots is sensitive to the employed particle diameter of the two-phase channel flow model. The larger the particle size, the more severe the maldistribution of temperature becomes. It is therefore concluded that further experimental validation and research into particle size modeling is necessary.
Original languageEnglish
JournalInternational Journal of Hydrogen Energy
Volume41
Issue number1
Pages (from-to)52–68
Number of pages17
ISSN0360-3199
DOIs
Publication statusPublished - Jan 2016

Fingerprint

two phase flow
electrolysis
Electrolysis
Two phase flow
Ion exchange
Flow fields
flow distribution
Anodes
Protons
anodes
membranes
Membranes
protons
Liquids
liquids
cells
Gases
gases
water
Water

Keywords

  • PEMEC
  • Water electrolysis
  • Modeling
  • Two-phase flow
  • High pressure

Cite this

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title = "A numerical study of the gas-liquid, two-phase flow maldistribution in the anode of a high pressure PEM water electrolysis cell",
abstract = "In this work, the use of a circular-planar, interdigitated flow field for the anode of a high pressure proton exchange membrane (PEM) water electrolysis cell is investigated in a numerical study. While PEM fuel cells have separated flow fields for reactant transport and coolant, it is possible to operate a PEM electrolysis cell with the anode flow field serving as both. This allows for a simpler system and a thinner design, however sets new and more strict requirements for the flow field to distribute uniformly. For the present study, two computational fluid dynamics models are developed; a single-phase flow model for establishing the effect of geometry and a two-phase flow model for studying the effect of dispersed gas bubbles. Both models account for turbulence and heat transport. By means of the developed models, it is elucidated that the circular-planar shape of the interdigitated flow field causes maldistribution, if land areas of equal width are applied. Moreover, below a water stoichiometry of 350, and at a current density of 1 A/cm2, flow and temperature maldistribution is adversely affected by the presence of the gas phase; particularly gas hold-up near outlet channels can cause excessive formation of hotspots. As the water stoichiometry increases, the flow maldistribution increases as well. Nonetheless, its impact on the temperature distribution is counterbalanced by an overall increase in heat capacity of the flow. Hence, a relative uniform temperature distribution is achieved at and above nominal flow conditions. In a parametric investigation it is further underlined that the predicted formation of hotspots is sensitive to the employed particle diameter of the two-phase channel flow model. The larger the particle size, the more severe the maldistribution of temperature becomes. It is therefore concluded that further experimental validation and research into particle size modeling is necessary.",
keywords = "PEMEC, Water electrolysis, Modeling, Two-phase flow, High pressure",
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A numerical study of the gas-liquid, two-phase flow maldistribution in the anode of a high pressure PEM water electrolysis cell. / Olesen, Anders Christian; Rømer, Carsten; Kær, Søren Knudsen.

In: International Journal of Hydrogen Energy, Vol. 41, No. 1, 01.2016, p. 52–68.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - A numerical study of the gas-liquid, two-phase flow maldistribution in the anode of a high pressure PEM water electrolysis cell

AU - Olesen, Anders Christian

AU - Rømer, Carsten

AU - Kær, Søren Knudsen

PY - 2016/1

Y1 - 2016/1

N2 - In this work, the use of a circular-planar, interdigitated flow field for the anode of a high pressure proton exchange membrane (PEM) water electrolysis cell is investigated in a numerical study. While PEM fuel cells have separated flow fields for reactant transport and coolant, it is possible to operate a PEM electrolysis cell with the anode flow field serving as both. This allows for a simpler system and a thinner design, however sets new and more strict requirements for the flow field to distribute uniformly. For the present study, two computational fluid dynamics models are developed; a single-phase flow model for establishing the effect of geometry and a two-phase flow model for studying the effect of dispersed gas bubbles. Both models account for turbulence and heat transport. By means of the developed models, it is elucidated that the circular-planar shape of the interdigitated flow field causes maldistribution, if land areas of equal width are applied. Moreover, below a water stoichiometry of 350, and at a current density of 1 A/cm2, flow and temperature maldistribution is adversely affected by the presence of the gas phase; particularly gas hold-up near outlet channels can cause excessive formation of hotspots. As the water stoichiometry increases, the flow maldistribution increases as well. Nonetheless, its impact on the temperature distribution is counterbalanced by an overall increase in heat capacity of the flow. Hence, a relative uniform temperature distribution is achieved at and above nominal flow conditions. In a parametric investigation it is further underlined that the predicted formation of hotspots is sensitive to the employed particle diameter of the two-phase channel flow model. The larger the particle size, the more severe the maldistribution of temperature becomes. It is therefore concluded that further experimental validation and research into particle size modeling is necessary.

AB - In this work, the use of a circular-planar, interdigitated flow field for the anode of a high pressure proton exchange membrane (PEM) water electrolysis cell is investigated in a numerical study. While PEM fuel cells have separated flow fields for reactant transport and coolant, it is possible to operate a PEM electrolysis cell with the anode flow field serving as both. This allows for a simpler system and a thinner design, however sets new and more strict requirements for the flow field to distribute uniformly. For the present study, two computational fluid dynamics models are developed; a single-phase flow model for establishing the effect of geometry and a two-phase flow model for studying the effect of dispersed gas bubbles. Both models account for turbulence and heat transport. By means of the developed models, it is elucidated that the circular-planar shape of the interdigitated flow field causes maldistribution, if land areas of equal width are applied. Moreover, below a water stoichiometry of 350, and at a current density of 1 A/cm2, flow and temperature maldistribution is adversely affected by the presence of the gas phase; particularly gas hold-up near outlet channels can cause excessive formation of hotspots. As the water stoichiometry increases, the flow maldistribution increases as well. Nonetheless, its impact on the temperature distribution is counterbalanced by an overall increase in heat capacity of the flow. Hence, a relative uniform temperature distribution is achieved at and above nominal flow conditions. In a parametric investigation it is further underlined that the predicted formation of hotspots is sensitive to the employed particle diameter of the two-phase channel flow model. The larger the particle size, the more severe the maldistribution of temperature becomes. It is therefore concluded that further experimental validation and research into particle size modeling is necessary.

KW - PEMEC

KW - Water electrolysis

KW - Modeling

KW - Two-phase flow

KW - High pressure

U2 - 10.1016/j.ijhydene.2015.09.140

DO - 10.1016/j.ijhydene.2015.09.140

M3 - Journal article

VL - 41

SP - 52

EP - 68

JO - International Journal of Hydrogen Energy

JF - International Journal of Hydrogen Energy

SN - 0360-3199

IS - 1

ER -