A two-dimensional two-phase mass transport model for direct methanol fuel cells adopting a modified agglomerate approach

Miao, Zheng; Li, Xianglin; Zou, Jinqiang

doi:10.1016/j.jpowsour.2008.06.007

Cited by 35 publications

(14 citation statements)

References 38 publications

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“…The modification factor O 2 in 14is obtained from the agglomerate model [22]. Overpotentials in (12) and 14are determined by profiles of solid phase potential and electrolyte phase potential in CLs, which are calculated from (11).…”

Section: Charge Transportmentioning

confidence: 99%

“…Earlier models are mainly single-phase models [9,[14][15][16]. In recent years, many twophase models have been developed for DMFCs [6][7][8][17][18][19][20][21][22] which can more realistically reflect the two-phase mass transport processes in the MEA. Ye et al [7] developed a 2D two-phase model to study the methanol and water crossover in an air-breathing DMFC.…”

Section: Introductionmentioning

confidence: 99%

“…In our former works, we also developed a 2D twophase transport model for active DMFCs [22]. This model was built on the classical liquid and vapor two-phase flow model in porous media.…”

Section: Introductionmentioning

confidence: 99%

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Modeling of the Transport Phenomena in Passive Direct Methanol Fuel Cells Using a Two-Phase Anisotropic Model

Miao

2014

Advances in Mechanical Engineering

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The transport phenomena in a passive direct methanol fuel cell (DMFC) were numerically simulated by the proposed twodimensional two-phase nonisothermal mass transport model. The anisotropic transport characteristic and deformation of the gas diffusion layer (GDL) were considered in this model. The natural convection boundary conditions were adopted for the transport of methanol, oxygen, and heat at the GDL outer surface. The effect of methanol concentration in the reservoir on cell performance was examined. The distribution of multiphysical fields in the membrane electrode assembly (MEA), especially in the catalyst layers (CLs), was obtained and analyzed. The results indicated that transport resistance for the methanol mainly existed in the MEA while that for oxygen and heat was primarily due to natural convection at the GDL outer surface. Because of the relatively high methanol concentration, the local reaction rate in CLs was mainly determined by the overpotential. Methanol concentration between 3 M and 4 M was recommended for passive liquid feed DMFC in order to achieve a balance between the cell performance and the methanol crossover.

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Section: Charge Transportmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Modeling of the Transport Phenomena in Passive Direct Methanol Fuel Cells Using a Two-Phase Anisotropic Model

Miao

2014

Advances in Mechanical Engineering

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“…In modeling of cells, stacks and systems, and in design of automatic control devices, a physically realistic analytical equation for the anode polarization curve is highly desirable. Many works utilize the Tafel law for the MOR rate in the electrode (Baxter et al 1999, Dohle et al 2000, Argyropoulos et al 2002, Murgia et al 2003, Yang and Zhao 2007, Casalegno and Marchesi 2008, Miao et al 2008, Cho et al 2009, Zhao et al 2009, Lam et al 2011. This extensive list reflects a great demand for a simple analytical expression for the MOR rate.…”

Section: Introductionmentioning

confidence: 99%

Analytical polarization curve of DMFC anode

Kulikovsky¹

2013

Advances in Energy Research

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A model for DMFC anode performance is developed. The model takes into account potential-independent methanol adsorption on the catalyst surface, finite rate of proton transport through the anode catalyst layer (ACL), and a potential loss due to methanol transport in the anode backing layer. An approximate analytical half-cell polarization curve is derived and equations for the anode limiting current density are obtained. The polarization curve is fitted to the curves measured by Nordlund and Lindbergh and parameters resulted from the fitting are discussed.

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“…The vast majority of these models are developed using a one-dimensional, steady state, isothermal, and single phase approach. Also, many models focused on the overall performance of the DMFC or are validated using only full-cell polarization data [24][25][26][27][28][29][30]. Some models are used to investigate in-depth a specific key area of the DMFC.…”

mentioning

confidence: 99%

Quantifying Individual Losses in a Direct Methanol Fuel Cell

García-Díaz

Patterson

Weidner

2011

Journal of Fuel Cell Science and Technology

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Studying the performance of a direct methanol fuel cell (DMFC) is complicated by the complex interactions of kinetic and transport processes. As a result, changes in one aspect of the cell have consequences in other aspects, which are difficult to elucidate from full-cell polarization (i.e., voltage versus current) behavior. This study outlines a strategy to use current and voltage relationships from anode half-cells, cathode half-cells, and hydrogen pump coupled with methanol crossover data and a mathematical model. In this way, all the kinetic and transport processes have been quantified, and the cell voltage was deconstructed (i.e., individual voltage losses were quantified). This data analysis accounts for all of the voltage losses observed during the operation of the full cell. As expected, the anode and cathode overpotentials accounted for most of the losses (i.e., 92% on average). Also, the cathode flow rate has been shown to affect the methanol crossover by diffusion. Cells operated at constant stoichiometry or where the cathode flow rate is small can show a parabolic shape in the methanol crossover because the electroosmotic drag dominates over diffusion as the primary transport mechanism for methanol through the membrane. Decrease in the methanol crossover was observed for cells with high compression and thicker cathode electrodes. The one-dimensional model, developed previously (García et al., 2004, “Mathematical Model 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 to reasonably predict the anode, cathode, full-cell polarization, and methanol crossover data for methanol concentrations between 0.05 M and 2 M at all operating currents.

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A two-dimensional two-phase mass transport model for direct methanol fuel cells adopting a modified agglomerate approach

Cited by 35 publications

References 38 publications

Modeling of the Transport Phenomena in Passive Direct Methanol Fuel Cells Using a Two-Phase Anisotropic Model

Modeling of the Transport Phenomena in Passive Direct Methanol Fuel Cells Using a Two-Phase Anisotropic Model

Analytical polarization curve of DMFC anode

Quantifying Individual Losses in a Direct Methanol Fuel Cell

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