A Dirichlet/Robin iteration-by-subdomain method for an anisotropic, nonisothermal two-phase transport model of PEM fuel cell with micro-porous layer

In this paper, we present a nonoverlapping domain decomposition method, Dirichlet/Robin type alternately iteration-by-subdomain method, for a 3D anisotropic, nonisothermal, multiphysics, two-phase transport model of proton exchange membrane fuel cell (PEMFC), particularly bearing micro-porous layer (MPL) and wet gas channel (GC). In this method, the necessary transmission conditions are introduced by nonlinear Dirichlet/Robin interfacial boundary conditions at the interfaces of some specific subdomains, i.e., of gas diffusion layer (GDL) and MPL due to the discontinuous liquid saturation (Pasaogullari and Wang, 2004) therein, and of GDL and GC due to the discontinuous Kirchhoff transformation arising from wet gas channel (Sun et al., 2009). We then use these transmission conditions to design a type of nonoverlapping domain decomposition method with the combined finite element-upwind finite volume discretizations to deal with water transports amongst such multi-layer diffusion media. Kirchhoff transformation and its inverse techniques are employed to overcome the discontinuous and degenerate water diffusivity in the coexisting single- and two-phase regions. Numerical simulations demonstrate that the present techniques are effective to obtain a fast and convergent nonlinear iteration for such a 3D multiphysics PEMFC model, in contrast to the oscillatory and nonconvergent iteration conducted by a standard finite element method.