Presents an application of the boundary element method to the analysis of magnetic fields in materials for which permeability depends non‐linearly on spatial co‐ordinates. A new…
Abstract
Presents an application of the boundary element method to the analysis of magnetic fields in materials for which permeability depends non‐linearly on spatial co‐ordinates. A new approach is proposed, which relates the Green’s function for non‐linearly dependent permeability to Green’s function of the Laplace equation in free space by adequate variable transformation. This can be done for very broad class magnetic permeabilities. These permeable functions, which cannot be directly used in such transformations, can be approximated by series of admissible functions.
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Eugeniusz Kurgan and Paweł Schmidt
Distribution of the electric potential and current density in the electrode of the proton exchange membrane fuel cell.
Abstract
Purpose
Distribution of the electric potential and current density in the electrode of the proton exchange membrane fuel cell.
Design/methodology/approach
Multicomponent model based on Maxwell‐Stefan equations is used to formulate generalized Fick's law. Next, mass conservation laws for gas components and equation of continuity for current density vector are formulated.
Findings
The problem is expressed by three non‐linear partial differential equations in total molar contraction of the gas mixture, oxygen and water vapor concentration describing multicomponent Maxwell‐Stefan mass transport and fourth equation for electric potential distribution. The final system of partial differential equations describing the problem is highly non‐linear and mutually coupled not only directly but also through the non‐linear boundary condition and is solved by finite element method.
Research limitations/implications
There are some convergence problems for some sets of the material parameters. Only one part of the fuel cell was modeled.
Practical implications
This approach allows one to calculate all important parameters required to develop and design the practical systems as well to optimize the performance from the geometrical and material parameters point of view.
Originality/value
The presented approach combines distribution of mass transport using Maxwell‐Stefan model and electric potential described by Laplace equation.