PARAMETRIC STUDY OF FLUID DYNAMICS IN PEM FUEL CELLS

This paper is a research in the frame of the Grant CEx 189/2006, "Water and thermic management for PEM fuel cells". We Study here the flow in the "Gas Diffusion Layer" of a PEM fuel cell. in this region, the dynamic of fluids is governed by capillary and diffusion phenomenon. The diffusion-convection process is studied, involving the oxygen and water vapors. Our model is similar with the Hele-Shaw model, which describes the displacement of two immiscible fluids with different viscosities between two parallel plates at a small distance (see [19]). The concentrations of the fluids are invertible in terms of the viscosities. If the displacing fluid is less viscous, the interface between the fluids is unstable. We consider a diffusion region between the two fluids, where the viscosity is a parameter. We study the linear stability of a basic solution, in terms of the diffusion coefficient. We get an upper estimate of the growth constant of perturbation. A large enough diffusion coefficient gives us a significant improvement of the flow stability.