A model for species diffusion is presented, with evaporation at a moving free boundary. The resulting problem resembles a one-phase Stefan problem with superheating, but the usual Stefan condition at the moving boundary is replaced by a version which, in the classical setting, would violate conservation of energy. In the fast evaporation limit, however, the problem reduces to a classical nonlin...

The Maxwell-Stefan (MS) approach is commonly used for describing mass transport by diffusion in gases and liquids since it correctly accounts for the chemical potential gradient as driving force. It is well known that MS diffusivities are concentration dependent which should be taken into account in practical applications. Unfortunately, it is difficult to obtain MS diffusivities both from expe...

We investigate the diffusion asymptotics of Boltzmann equation for gaseous mixtures, in perturbative regime around a local Maxwellian vector whose fluid quantities solve flux-incompressible Maxwell–Stefan system. Our framework is torus and we consider hard-potential collision kernels with angular cutoff. As opposed to existing results about hydrodynamic limits mono-species case, study here not ...

This paper explores the mathematical formulations of Fick and MaxwellStefan diffusion in the context of polymer electrolyte membrane fuel cell cathode gas diffusion layers. Formulations of diffusion combined with mass-averaged Darcy flow are considered for three component gases. Fick formulations can be considered as approximations of Maxwell-Stefan in a certain sense. For this application, the...

In this study the laws of mechanics for multi-component systems are used to develop a theory for the diffusion of ions in the presence of an electrostatic field. The analysis begins with the governing equation for the species velocity and it leads to the governing equation for the species diffusion velocity. Simplification of this latter result provides a momentum equation containing three domi...

B [±] deformation factor cL [eq(H )/l] H ion exchange capacity related to catalyst volume ct [mol/l] total molar concentration Deff [m /s] effective transport coefficient D [m/s] transport coefficient in gel phase or liquid phase ÐDij [m /s] binary Maxwell-Stefan diffusion coefficient of pair i-j m1 [±] volumetric distribution ratio of component 1 N [±] number of components N1 [mol/(m 2 s)] mol...

The transport of three gas species, O2, H2O and N2, through the cathode of a proton exchange membrane (PEM) fuel cell is studied numerically. The diffusion of the individual species is modeled via the Maxwell–Stefan equations, coupled with appropriate conservation equations. Two mechanisms are assumed for the internal energy sources in the system: a volumetric heat source due to the electrical ...