Application of an Effective Medium Formulation to Account for Transport Due to Fiber and Web-like Inclusions in Gas Diffusion Layers. Issue 7 (28th March 2015)

• Record Type: Journal Article
• Authors: Myles, Timothy D.; Peracchio, Aldo A.; Pasaogullari, Ugur; Chiu, Wilson K. S.
• Is Part Of: Journal of the Electrochemical Society. Volume 162:Issue 7(2015)
• Page Start: F645
• Page End: F650
• Publication Date: 2015-03-28
• Subjects: anisotropy -- effective medium theory -- gas diffusion layer; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.0131507jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : The versatility of a recently developed analytical effective medium theory (EMT) is tested by mimicking the structure of gas diffusion layer materials. The EMT was derived in a previous study [T. D. Myles, A. A. Peracchio, and W. K. S. Chiu, J. Appl. Phys., 115, 203503 (2014); T. D. Myles, A. A. Peracchio, and W. K. S. Chiu, J. Appl. Phys., 117, 025101 (2015)] and is based on the Bruggeman unsymmetrical theory. This EMT calculates the effective transport property of a mixture consisting of multiple types of inclusion particles, which are spheroid shaped and have varying orientation anisotropy, embedded in a continuous matrix. Each inclusion type may have a unique bulk transport property, orientation anisotropy, and shape. As a starting point, the theory was first tested against a commonly cited numerical result from the literature for effective diffusivity through fibrous structures. From there the EMT was modified to account for web-like structures that develop in Toray carbon paper materials. Finally, the in-plane thermal conductivity of the carbon paper was predicted. The results show good agreement to available numerical and experimental data in the literature despite the relatively simple expressions and implementation. However, one issue which was highlighted in this study was the lack of accounting for percolation phenomena in the developed EMT.