A pore-level direct numerical investigation of water evaporation characteristics under air and hydrogen in the gas diffusion layers of polymer electrolyte fuel cells

Safi, Mohammad Amin; Mantzaras, John; Prasianakis, Nikolaos I.; Lamibrac, Adrien; Büchi, Félix N.

doi:10.1016/j.ijheatmasstransfer.2018.10.042

Cited by 20 publications

(13 citation statements)

References 33 publications

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“…The artificial distribution of hydrophobic and hydrophilic GDL domains enables tailormade patterns of water filled lines with high levels of evaporation rates and necessitates a good understanding of the vapor removal mechanisms, ultimately limiting the rate of evaporation. Understanding the characteristic mechanisms and limitations to evaporative water removal in the framework of PEFCs and quantifying them has been the aim of many scientific works, both experimentally [21][22][23][24][25] and numerically [26][27][28][29][30][31][32]. However, the reported evaporation values show a wide spread [31,33] and some measurements performed on differential cell scales leave open questions of how evaporative flux scales with GDL thickness and gas type are used in the evaporation rate measurements, as reported by Lal et al [21].…”

Section: Introductionmentioning

confidence: 99%

Mass Transport Limitations of Water Evaporation in Polymer Electrolyte Fuel Cell Gas Diffusion Layers

et al. 2021

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Facilitating the proper handling of water is one of the main challenges to overcome when trying to improve fuel cell performance. Specifically, enhanced removal of liquid water from the porous gas diffusion layers (GDLs) holds a lot of potential, but has proven to be non-trivial. A main contributor to this removal process is the gaseous transport of water following evaporation inside the GDL or catalyst layer domain. Vapor transport is desired over liquid removal, as the liquid water takes up pore space otherwise available for reactant gas supply to the catalytically active sites and opens up the possibility to remove the waste heat of the cell by evaporative cooling concepts. To better understand evaporative water removal from fuel cells and facilitate the evaporative cooling concept developed at the Paul Scherrer Institute, the effect of gas speed (0.5–10 m/s), temperature (30–60 °C), and evaporation domain (0.8–10 mm) on the evaporation rate of water from a GDL (TGP-H-120, 10 wt% PTFE) has been investigated using an ex situ approach, combined with X-ray tomographic microscopy. An along-the-channel model showed good agreement with the measured values and was used to extrapolate the differential approach to larger domains and to investigate parameter variations that were not covered experimentally.

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Section: Introductionmentioning

confidence: 99%

Mass Transport Limitations of Water Evaporation in Polymer Electrolyte Fuel Cell Gas Diffusion Layers

et al. 2021

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“…In this study, the guided equilibrium model , was employed to calculate the equilibrium distribution f i eq . Additional implementation details are given in refs , , and .…”

Section: Methodsmentioning

confidence: 99%

Validating the Transition Criteria from the Cassie–Baxter to the Wenzel State for Periodically Pillared Surfaces with Lattice Boltzmann Simulations

Jäger,

Mokos,

Prasianakis

et al. 2024

ACS Omega

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Microfabrication techniques allow the development and production of artificial superhydrophobic surfaces that possess a precisely controlled roughness at the micrometer level, typically achieved through the arrangement of micropillar structures in periodic patterns. In this work, we analyze the stability and energy barrier of droplets in the Cassie−Baxter (CB) state on such periodic patterns. In addition, we further develop a transition criterion using the CB equation and derive an improved version which allows predicting for which pillar geometries, equilibrium contact angles, and droplet volumes the CB state switches from a metastable to an unstable state. This enables a comparison with existing experiments and three-dimensional multiphase Lattice Boltzmann simulations for different pillar distances, two contact angles, and two droplet volumes, where a good agreement has been found.

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“…Additionally, experimental studies of evaporative cooling have been conducted at material, cell, stack and system level and the phase change as well as the transport of water in GDLs has been studied extensively [40][41][42][43][44][45][46].…”

Section: Introductionmentioning

confidence: 99%

Evaporative cooling for polymer electrolyte fuel cells - An operando analysis at technical single cell level

Striednig

Mularczyk

Liu

et al. 2023

Journal of Power Sources

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A pore-level direct numerical investigation of water evaporation characteristics under air and hydrogen in the gas diffusion layers of polymer electrolyte fuel cells

Cited by 20 publications

References 33 publications

Mass Transport Limitations of Water Evaporation in Polymer Electrolyte Fuel Cell Gas Diffusion Layers

Mass Transport Limitations of Water Evaporation in Polymer Electrolyte Fuel Cell Gas Diffusion Layers

Validating the Transition Criteria from the Cassie–Baxter to the Wenzel State for Periodically Pillared Surfaces with Lattice Boltzmann Simulations

Evaporative cooling for polymer electrolyte fuel cells - An operando analysis at technical single cell level

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