Simulation of the Oxygen Reduction Reaction (ORR) Inside the Cathode Catalyst Layer (CCL) of Proton Exchange Membrane Fuel Cells Using the Kinetic Monte Carlo Method

In this paper, a numerical model of the kinetic Monte Carlo (KMC) method has been developed to study the oxygen reduction reaction (ORR) that occurs inside the cathode catalyst layer (CCL). Firstly, a 3-D model of the CCL that consists of Pt and carbon spheres is built using the sphere packing method; secondly, an efficient procedure of the proton-oxygen reaction process is developed and simulated. In the proton-oxygen reaction process, all of the continuous movements of protons and oxygen are considered. The maximum reaction distance is determined to be 8 Å. The input pressures of protons and oxygen are represented by the number of spheres of the species. The value of the current density is calculated based on the amount of reaction during the interval time. Indications are that the results of the present model match reasonably well with the published results. A new way to apply the KMC method in the proton exchange membrane fuel cell (PEMFC) research field is developed in this paper

Cross section design of holey optical fibers with coating based on stress analysis in tension

In this paper, the mechanical behavior of newly developed holey optical fibers with and without coating was investigated by numerical analysis. Based on experimental work, the tensile failure characteristics were observed. The stress characteristics of some typical holey fibers with different section design were studied though the finite element method under tensile load. The optimum design of air hole arrangements and sizes were proposed according to the numerical results. The influence of the coating thickness on the axial stress of holey optical fiber was also investigated. The numerical results and conclusions will be useful for the cross section optimum design of holey optical fiber for increase its strength