2134/10516
Yuan Gao
Yuan
Gao
Xiaoxian Zhang
Xiaoxian
Zhang
Pratap Rama
Pratap
Rama
Rui Chen
Rui
Chen
Hossein Ostadi
Hossein
Ostadi
Kyle Jiang
Kyle
Jiang
An improved MRT lattice Boltzmann model for calculating anisotropic permeability of compressed and uncompressed carbon cloth gas diffusion layers based on x-ray computed micro-tomography
Loughborough University
2012
Multiple-relaxation time (MRT)
Lattice Boltzmann method
Anisotropic permeability
Carbon cloth gas diffusion layer
Compressed and uncompressed GDLs
Engineering not elsewhere classified
2012-10-02 11:04:16
Journal contribution
https://repository.lboro.ac.uk/articles/journal_contribution/An_improved_MRT_lattice_Boltzmann_model_for_calculating_anisotropic_permeability_of_compressed_and_uncompressed_carbon_cloth_gas_diffusion_layers_based_on_x-ray_computed_micro-tomography/9229595
The gas diffusion layers (GDLs) in polymer proton exchange membrane fuel cells are
under compression in operation. Understanding and then being able to quantify the
reduced ability of GDLs to conduct gases due to the compression is hence important in
fuel cell design. In this paper, we investigated the change of anisotropic permeability of
GDLs under different compressions using the improved multiple-relaxation time (MRT)
lattice Boltzmann model and X-ray computed micro-tomography. The binary 3D X-ray
images of GDLs under different compressions were obtained using the technologies we
developed previously, and the permeability of the GDLs in both through-plane and inplane
directions was calculated by simulating gas flow at micron scale through the 3D
images. The results indicated that, in comparison with the single-relaxation time (SRT)
lattice Boltzmann model commonly used in the literature, the MRT model is robust and
flexible in choosing model parameters. The SRT model can give accurate results only
when using a specific relaxation parameter whose value varies with porosity. The simulated
results using the MRT model reveal that compression could lead to a significant
decrease in permeability in both through-plane and in-plane directions, and that the relationship
between the decreased permeability and porosity can be well described by both
Kozeny-Carman relation and the equation derived by Tomadakis and Sotirchos (1993,
“Ordinary and Transition Rdgime Diffusion in Random Fiber Structure,” AIChE J., 39,
pp. 397–412) for porosity in the range from 50% to 85%. Since GDLs compression takes
place mainly in the through-plane direction, the results presented in this work could provide
an easy way to estimate permeability reduction in both through-plane and in-plane
directions when the compressive pressure is known.