Effects of heterogeneous surface of gas diffusion layers on droplet transport in microchannels of PEM fuel cells

Ashrafi, Moosa; Shams, Mehrzad

doi:10.1016/j.ijhydene.2015.11.096

Cited by 24 publications

(8 citation statements)

References 47 publications

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“…Ding et al [31,32], and Hossain et al [52] reproduced the microstructure of a GDL by means of a circular pore mesh. Recently, Ashrafi and Shams [10] studied effects of GDL roughness in a two-dimensional study, where roughness size and distribution was randomly generated for several cases. Chen et al considered a regular set of cubic indentations on the GDL surface, representing Cassie approximation of surface roughness [19][20][21].…”

Section: Vof Modeling Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Challenges in Computational Modeling of Two-Phase Transport in Polymer Electrolyte Fuel Cells Flow Channels: A Review

Jarauta

Ryzhakov

2017

Arch Computat Methods Eng

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Excess of liquid water in gas channels of polymer electrolyte fuel cells is responsible for malfunctioning of these devices. Not only it decreases their efficiency via partial blockage of reactants and pressure drop, but it can also lead to the irreversible damage due to oxygen starvation in case of complete channel flooding or full coverage of the gas diffusion layer with a liquid film. Liquid water evacuation is carried out via airflow in gas channels. Several experimental and computational techniques have been applied to date for the analysis of the coupled airflow-water behavior in order to understand the impact of fuel cell design and operation regimes upon the liquid water accumulation. Considerable progress has been achieved with the development of sophisticated computational fluid dynamics (CFD) tools. Nevertheless, the complexity of the problem under consideration leaves several issues unresolved. In this paper, analysis techniques applied to liquid water-airflow transport in fuel cells gas channels are reviewed and most important results are summarized. Computationally efficient, yet strongly simplified analytical models are discussed. Afterwards, CFD approaches including the conventional fixed grid (Eulerian) and the novel embedded Eulerian-Lagrangian models are described. Critical comparative assessment of the existing methods is provided at the end of the paper and the unresolved issues are highlighted.

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Section: Vof Modeling Resultsmentioning

confidence: 99%

“…At continuous level the fictitious Eulerian domain exactly coincides with the Lagrangian domain and Γ I = Γ L . Γ s defines the boundary of the liquid phase that in contact with the solid.The governing system in either domain is the Navier-Stokes equations equipped with the incompressibility condition (Eqs (10),(11)…”

mentioning

confidence: 99%

Challenges in Computational Modeling of Two-Phase Transport in Polymer Electrolyte Fuel Cells Flow Channels: A Review

Jarauta

Ryzhakov

2017

Arch Computat Methods Eng

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“…The real microstructure of GDL surface was replaced by some regular geometries for the sake of simplification. Ashrafi and Shams [21] used the 2D VOF method to investigate the movement process of liquid droplet on the GDL surface generated by a random function. Anyanwu et al [22] used a reconstructed GDL as the bottom of GC to study the droplet behavior on GDL through the VOF model.…”

Section: Introductionmentioning

confidence: 99%

Dynamic behavior of droplet transport on realistic gas diffusion layer with inertial effect via a unified lattice Boltzmann method

Yang

Fei

Zhang

et al. 2021

International Journal of Hydrogen Energy

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“…Nevertheless, studies on fiber diameter impact on product water transport behavior and removal on a reconstructed GDL carbon cloth are very scarce. Based on the available literature, evaluation of two-phase flows in reconstructed GDL microstructures is carried out using various models such as the pore-network modeling (PNM) [21][22][23], the lattice Boltzmann method (LBM) [10,24] and the volume of fluid (VOF) method [9,15,[25][26][27][28][29][30][31][32]. These popular methods have their strengths and weaknesses.…”

Section: Introductionmentioning

confidence: 99%

“…These were used as assumptions in their work, while microscopic roughness of fiber ridges was neglected. To address this issue, Ashrafi and Shams 2016 [32] developed a 2D two-phase VOF model to study the effect of the GDL heterogeneous surface on droplet transport in PEMFC channels. They used a random function to generate a non-uniform GDL surface in terms of roughness density and roughness height.…”

Section: Introductionmentioning

confidence: 99%

Liquid Water Transport Behavior at GDL-Channel Interface of a Wave-Like Channel

et al. 2020

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This paper evaluates the liquid water at the gas diffusion layer-channel (GDL-channel) interface of reconstructed GDL microstructures with uniform and non-uniform fiber diameters in wave-like channels. A non-uniform GDL microstructure is reconstructed for the first time at the GDL-channel interface to evaluate droplet motion. The three-layer GDL microstructures are generated using the stochastic technique and implemented using the OpenFOAM computational fluid dynamics (CFD) software (OpenFOAM-6, OpenFOAM Foundation Ltd., London, UK). The present study considers the relationship between reconstructed GDL surfaces with varying fiber diameters, wettability, superficial inlet velocity and droplet size. Results show that the droplet detachment and the average droplet velocity decrease with an increase in the fiber diameter as well as the structural arrangement of the fibers. Under the non-uniform fiber arrangement, the removal rate of water droplets is not significantly improved. However, the choice of smaller fiber diameters facilitates the transport of droplets, as hydrophobicity increases even at slight surface roughness. The results also indicate that the average droplet velocity decreases under low inlet velocity conditions while increasing under high inlet velocity conditions. Therefore, the structural make-up of the GDL-channel interface influences the droplet dynamics, and the implementation of a non-uniform GDL structure should also be considered in the GDL designs.

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Effects of heterogeneous surface of gas diffusion layers on droplet transport in microchannels of PEM fuel cells

Cited by 24 publications

References 47 publications

Challenges in Computational Modeling of Two-Phase Transport in Polymer Electrolyte Fuel Cells Flow Channels: A Review

Challenges in Computational Modeling of Two-Phase Transport in Polymer Electrolyte Fuel Cells Flow Channels: A Review

Dynamic behavior of droplet transport on realistic gas diffusion layer with inertial effect via a unified lattice Boltzmann method

Liquid Water Transport Behavior at GDL-Channel Interface of a Wave-Like Channel

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