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Catalyst layers computational domain

Recently, a new class of stochastic CL models has been developed (Mukherjee and Wang, 2006). These models simulate species transport in a small 3D domain of the catalyst layer. The domain is subdivided into elementary computational cells representing either a void space or an electrolyte/carbon phase. The structure of this domain is obtained by the stochastic reconstruction of micro-images of real catalyst layers. [Pg.82]

Fig. 20 Boundary conditions for gases, concentration and potentials. The computational domain for the anode side gases and potentials is depicted by bold line (the domain for membrane phase potential rpe includes both catalyst layers and membrane). Shown are conditions at the anode the same conditions are imposed on the cathode side. Conditions along the left and right sides are obtained on each iteration step from the neighbors (physical boundary conditions are fixed at the left side of the leftmost and at the right side of the rightmost elements). Fig. 20 Boundary conditions for gases, concentration and potentials. The computational domain for the anode side gases and potentials is depicted by bold line (the domain for membrane phase potential rpe includes both catalyst layers and membrane). Shown are conditions at the anode the same conditions are imposed on the cathode side. Conditions along the left and right sides are obtained on each iteration step from the neighbors (physical boundary conditions are fixed at the left side of the leftmost and at the right side of the rightmost elements).
The same authors developed this model further by transforming the volumetric catalyst layer source terms into interfacial boundary conditions for a full three-dimensional fuel-cell model [23]. The catalyst surface is represented as a two-dimensional plane, which is coupled to computational fluid dynamics (CFD) code. The modeling domain includes a channel pair with ribs and MEA. [Pg.822]

The flow in the gas channels and in the porous gas diffusion electrodes is described by the equations for the conservation of momentum and conservation of mass in the gas phase. The solution of these equations results in the velocity and pressure fields in the cell. The Navier-Stokes equations are mostly used for the gas channels while Darcy s law may be used for the gas flow in the GDL, the microporous layer (MPL), and the catalyst layer [147]. Darcy s law describes the flow where the pressure gradient is the major driving force and where it is mostly influenced by the frictional resistance within the pores [145]. Alternatively, the Brinkman equations can be used to compute the fluid velocity and pressure field in porous media. It extends the Darcy law to describe the momentum transport by viscous shear, similar to the Navier-Stokes equations. The velocity and pressure fields are continuous across the interface of the channels and the porous domains. In the presence of a liquid phase in the pore electrolyte, two-phase flow models may be used to account for the interaction between the gas phase and the liquid phase in the pores. When calculating the fluid flow through the inlet and outlet feeders of a large fuel cell stack, the Reynolds-averaged Navier-Stokes (RANS), k-o), or k-e turbulence model equations should be used due to the presence of turbulence. [Pg.396]


See other pages where Catalyst layers computational domain is mentioned: [Pg.498]    [Pg.276]    [Pg.508]    [Pg.2980]    [Pg.298]    [Pg.439]    [Pg.409]   
See also in sourсe #XX -- [ Pg.234 ]




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Computer domain

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