... mass transfer coefficients through limiting current measurements. Finally, we combine these findings to develop power law relations between relevant dimensional and dimensionless quantities and to calculate extensive mass transfer coefficients. These studies reveal nuanced relationships between...

... regions where y w = | ε | , which would be impossible in reality. Such in-plane gradients do not arise for one-dimensional models. Fig. 3 Typical calculated species distribution in an SOFC cathode where g is a mass transfer coefficient, based on local minimum value wall...

... . 1 Corresponding author. Manuscript received December 10, 2016; final manuscript received April 20, 2017; published online June 21, 2017. Assoc. Editor: Matthew Mench. 10 12 2016 20 04 2017 PEM fuel cells cathode channel wavy surface mass transfer numerical modeling...

... [3] Chiu , W. K. S. , Joshi , A. S. , and Grew , K. N. , 2009 , “ Lattice Boltzmann Model for Multi-Component Mass Transfer in a Solid Oxide Fuel Cell Anode With Heterogeneous Internal Reformation and Electrochemistry ,” Eur. Phys. J. Spec. Top. , 171 , pp. 159 – 165 . 10.1140/epjst...

... of a Direct Methanol Fuel Cell,” J. Fuel Cell Sci. Technol., 1 (1), pp. 43–48), was improved by: (1) including methanol transport from the anode flow channel to the backing layer using a mass transfer resistance and (2) accounting for the unreacted methanol transport through the cathode. The model was able...

... zero arises from the competing heat and mass transfer dynamics, and is determined by the structural parameters and membrane properties. A sensitivity study is presented and shows that structural and material property optimization can be used with the control system design to mitigate the non-minimum...

... , Fundamentals of Heat and Mass Transfer , 3rd ed. , Wiley , New York . V volt ( V ) I current ( A ) T temperature ( ° C , K ) M molar mass of a substance ( mole ) c number of cells...

... for a commercial system. In a stack, heat and mass transfer, which affects the performance, is altered by manifold structures. Therefore, this paper studied three kinds of manifold designs using numerical analyses. Governing equations and electrochemical reaction models were calculated simultaneously to conduct...

... to measure the dynamic response of electrodes. Mass transfer behavior was analyzed using equations for diffusion in finite lengths of thin film electrolytes covering the catalyst surface area. Electrode structure parameters were measured using SEM images of the cross section of the membrane electrode...

...Joonguen Park; Joongmyeon Bae This paper studies the heat and mass transfer characteristics in a steam reforming reactor using numerical simulation and investigates the operating parameters for effective hydrogen production. Simultaneous analysis of governing equations and chemical reaction...

... transport for Nafion ® 21 x membranes will be presented. A mass-transfer coefficient for the interfacial resistance is calculated from experimental data using different permeation cells. This coefficient is shown to depend exponentially on relative humidity or water activity. The interfacial resistance does...

.... 1381 – 1383 . 10.1016/j.elecom.2008.07.013 Greene , E. S. , Chiu , W. K. S. , and Medeiros , M. G. , 2006 , “ Mass Transfer in Graded Microstructure Solid Oxide Fuel Cell Electrodes ,” J. Power Sources 0378-7753 , 161 , pp. 225 – 231 . 10.1016/j.jpowsour.2006.03.063...

...Joonguen Park; Shinku Lee; Sunyoung Kim; Joongmyeon Bae This paper discusses a numerical analysis of the heat and mass transfer characteristics in an autothermal methane reformer. Assuming local thermal equilibrium between the bulk gas and the surface of the catalyst, a one-medium approach...

... takes account of momentum, heat, and mass transfer in and around the cell, including the effects of radiation, internal reforming, and electrochemical reactions. The biogas, which is fed into the reformer with steam, is assumed to be composed of methane ( CH 4 ) and carbon dioxide ( CO 2 ) . The results...

..., it is necessary to couple the heat and mass transfer to accurately model the species conversion of the reformate stream. The reactions in the SOFC contribute much less to the temperature distribution than in the reformer and therefore the heat transfer in the SOFC is not necessary to model. A packed bed reactor...

... of this system. For the analysis, we develop a detailed control-oriented model of the system that captures the heat and mass transfer, chemical kinetics, and electrochemical phenomena. We express the dynamics of the reformer and the fuel cell in state-space form. By applying coordinate transformations...

... voltage undershoot following a decrease in load demand. On the other hand, due to their faster dynamics the mass transfer and electrochemistry processes are assumed instantaneous. The hybridizing device, whose main purpose is to assist the SOFC system (i.e., stack and ancillaries) during transient...

... for the constitutive j MEA relationship for each GDL as described in Eq. 3 are displayed in Table 3 . 16 06 2007 29 11 2007 14 08 2009 current density diffusion mass transfer proton exchange membrane fuel cells The ribbon fuel cell relies on the gas diffusion layer...

... cells is the feeding of the electrode with reactants and the removal of products. proton exchange membrane fuel cell air-breathing cathode porous transports chemically reactive flow current density electrochemical electrodes finite element analysis mass transfer orifices...

... transfer and electrical contact resistance. Existing research for analyzing the assembly pressure effects is mostly experimental. This paper develops a sequential approach to study the pressure effects by combining the mechanical and electrochemical phenomena in fuel cells. The model integrates gas mass...