scholarly journals Some Aspects of Mass Transfer Within the Passages of Fuel Cells

2003 ◽  
Author(s):  
S. B. Beale
Keyword(s):  
Mass Transfer ◽  
Fuel Cells ◽  
Heat Mass Transfer ◽  
Driving Force ◽  
Transfer Problem ◽  
Scalar Transport ◽  
Square Duct ◽  
Mass Transfer Problem

This paper describes a numerical heat/mass transfer analysis for planar and square duct geometries, found in certain fuel cells. Both developing and fully-developed scalar transport are considered. The solution to the heat/mass transfer problem is presented in terms of normalized conductance as a function of the driving force and wall Reynolds/Peclet numbers.

Conjugate Mass Transfer in Gas Channels and Diffusion Layers of Fuel Cells

2005 ◽  
Author(s):  
S. B. Beale
Keyword(s):  
Mass Transfer ◽  
Driving Force ◽  
Transfer Problem ◽  
Computational Procedure ◽  
Diffusion Layers ◽  
Blockage Factor ◽  
Mass Transfer Problem ◽  
Blowing Parameter ◽  
Mathematical Foundations ◽  
And Diffusion

An analysis is performed for mass transfer in a rectangular gas passage, porous diffusion layer, and the combination of the two. The results of detailed calculations are presented and correlated in terms of the mass transfer driving force as a function of the blowing parameter and geometry, as characterized by the aspect ratio and blockage factor. It is shown that a simple solution for the overall driving force may be obtained for the conjugate mass transfer problem. This solution is quite general in its nature. The mathematical foundations are presented together with the details of the computational procedure used to obtain the results.

scholarly journals Conjugate Mass Transfer in Gas Channels and Diffusion Layers of Fuel Cells

2006 ◽  
Vol 4 (1) ◽  
pp. 1-10 ◽  
Author(s):  
S. B. Beale
Keyword(s):  
Mass Transfer ◽  
Fuel Cells ◽  
Diffusion Layer ◽  
Driving Force ◽  
Transfer Problem ◽  
Analytical Methodology ◽  
Diffusion Layers ◽  
Wide Range ◽  
Simple Mass ◽  
Blowing Parameter

Prediction of mass transfer effects is a key element in fuel cell design. In this paper, the results of a generalized analysis appropriate to a wide range of designs and flow conditions are presented. Mass transfer in a rectangular gas passage, diffusion layer, and the combination of the two is considered. Fully developed viscous flow is presumed to occur within the passage, while the incompressible form of Darcy’s law is prescribed for the diffusion layer. The mathematical foundations for a simple mass transfer analysis are presented. Detailed calculations are then performed by means of a computational fluid dynamics code. These results are then correlated according to the analytical methodology in terms of nondimensional numbers appropriate to mass transfer analysis; namely, the overall mass transfer driving force as a function of the blowing parameter. Parametric studies are performed for a range of geometries, as characterized by the aspect ratio and blockage factor. It is shown that a simple solution for the overall driving force may readily be obtained from the two individual solutions for the conjugate mass transfer problem. This solution is quite general in its nature, and may readily be used to predict concentration polarization effects for a variety of fuel cells.

Generalized Transient Leveque Problem

1996 ◽  
Vol 61 (9) ◽  
pp. 1267-1284
Author(s):  
Ondřej Wein
Keyword(s):  
Mass Transfer ◽  
Exact Solution ◽  
Shear Rate ◽  
Transfer Problem ◽  
Numerical Data ◽  
Wall Shear Rate ◽  
Response Operator ◽  
Mass Transfer Problem ◽  
Finite Step ◽  
General Response

Response of an electrodiffusion friction sensor to a finite step of the wall shear rate is studied by numerically solving the relevant mass-transfer problem. The resulting numerical data on transient currents are treated further to provide reasonably accurate analytical representations. Existing approximations to the general response operator are checked by using the obtained exact solution.

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