Numerical study on permeability of gas diffusion layer with porosity gradient using lattice Boltzmann method

et al. 2022

Self Cite

Proton exchange membrane fuel cells (PEMFCs) have the advantages of high specific power, good stability, and zero emissions, making them clean and efficient energy conversion devices. Water management is one of the technical challenges limiting the development of PEMFC, with liquid water blocking the pores and increasing the resistance to mass transport. In this paper, a two-dimensional (2D) multiphase lattice Boltzmann (LB) model is developed to obtain the liquid water morphology within the gas diffusion layer (GDL). A 2D multicomponent flow Lattice Boltzmann model considering electrochemical reactions is established to investigate the effects of water saturation, activation overpotential, and pressure difference between the inlet and outlet gas channels on mass transport. At high water saturation, the liquid water forms water films within the GDL preventing reactive gas transport and water vapor are blocked near the catalyst layer making it difficult to remove. The PEMFC can achieve higher current densities at high activation overpotentials, but oxygen starvation will be exacerbated. Increasing the pressure difference between the inlet and outlet gas passages effectively increases the oxygen concentration and reduces the water vapor concentration in the GDL. The present study improves the understanding of the effect of GDL microstructure on mass transport and performance of PEMFC from the mesoscopic scale.

Section: Computational Domain and Boundarysupporting

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Pore-Scale Modeling of Mass Transport in Partially Saturated Cathode Gas Diffusion Layers of Proton Exchange Membrane Fuel Cell

Wang

et al. 2022

Self Cite

“…The 3D structure of the GDL is generated by a stochastic reconstruction method, the details of which are described in previous works. − The planar structure that meets the porosity requirement is selected for the 2D melting calculation, and for in-plane it is also necessary to ensure that the fiber diameter meets the set value. To investigate the effect of fiber diameter on the anisotropic melting process, the porosity of the porous structure is chosen to be 0.7.…”

Section: Mathematical Modelingmentioning

confidence: 99%

Investigation of the Ice Melting Process in a Simplified Gas Diffusion Layer of Fuel Cell by the Lattice Boltzmann Method

Jiang

et al. 2022

Self Cite

Cold start is a challenge for the proton exchange membrane fuel cell, and understanding the heat transfer characteristics of solid–liquid phase change in this process is necessary. An enthalpy-based lattice Boltzmann model is established, and the heat transfer of ice melting in in-plane and through-plane of the gas diffusion layer (GDL) is studied. The effects of fiber diameter, double heat sources, and Rayleigh number are analyzed. It is found that the fiber diameter has a significant influence on heat transfer. The ice melting rate of XZ position is faster than other planes, and it has the best effect when the diameter is 8 μm. The heat transfer of different heating positions is analyzed, and it is found that the left-right-heated has the highest melting efficiency. The heat sources location has different effects on the heat transfer between the XY position (TP1) and YZ position (TP2). Although the increase of Rayleigh number can enhance the convective heat transfer, the change of melting efficiency is extremely small. The convective heat transfer intensity has no direct effect on the ice melting of GDL, and fiber plays a more critical role in the heat transfer of ice melting.

“…Froning et al also verified that the computational domain size of 100 × 150 × 100 lu 3 is large enough to study the single-phase single-component flow in the GDL. In this paper, the initial target porosity of the fiber is 0.6–0.9, − and more details of the stochastic reconstruction model can be found in our previous work. , …”

Section: Model Descriptionmentioning

confidence: 99%

Transport-Parameter-Based Correlations for Gas Diffusion Layers Considering Compression and Binder: An Investigation Using the Lattice Boltzmann Method

Wang

et al. 2021

Self Cite

The mesoscopic three-dimensional (3D) lattice Boltzmann (LB) model is employed to investigate the transport parameters for the gas diffusion layer (GDL) of a proton-exchange membrane fuel cell, and the corresponding correlations are proposed. The effects of the binder and the compression caused by the assembly pressure on the permeability, diffusivity, and tortuosity are discussed. The GDL fiber skeleton samples are first reconstructed using the stochastic reconstruction algorithm, and samples with various binder volume fractions and various compression ratios are generated. The 3D LB model is subsequently implemented to simulate the single-phase gas flow characteristics in the GDL, and the transport parameters are calculated after the fluid reached the steady state. The simulation results indicate that the increase in the binder volume fraction and compression ratio results in a more complex GDL structure, leading to a decline in permeability and diffusivity and an increase in tortuosity. The fitted multi-factor transport parameter prediction correlations that consider fiber skeleton porosity, binder volume fraction, and compression ratio have more accurate prediction characteristics than the single-factor transport parameter prediction correlations that only consider the GDL porosity.