Extended equation fuel cells

Xu et al. (2006b) have successfully introduced Brinkman-Forchheimer-extended Darcy equation in order to solve the performance of molten carbonate fuel cell. As a verification of REV method, Poiseuille flow profiles in the porous media modifying LBM with... 

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. 

In the slab geometry, the cell may be taken as a block of unit cross section extending from x = 0tox = 6 so that Vy — volume of fuel in unit cell = a F Af = volume of moderator in unit cell = b — a Equation (10.58) may then be written ... 

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