Show simple item record

dc.contributor.authorChan, Carl 16:04:50 (GMT) 16:04:50 (GMT)
dc.description.abstractAccuracy in the effective diffusion coefficient of the gas diffusion layer (GDL)/microporous layer (MPL) is important to accurately predict the mass transport limitations for high current density operation of polymer electrolyte membrane (PEM) fuel cells. All the previous studies regarding mass transport limitations were limited to pure GDLs, and experimental analysis of the impact of the MPL on the overall diffusion in the porous GDL is still lacking. The MPL is known to provide beneficial water management properties at high current operating conditions of PEM fuel cells but its small pore sizes become a resistance in the diffusion path for mass transport to the catalyst layer. A modified Loschmidt cell with an oxygen-nitrogen mixture is used in this work to determine the effect of MPL on the effective diffusion coefficients. It is found that Knudsen effects play a dominant role in the diffusion through the MPL where pore diameters are less than 1 μm. Experimental results show that the effective diffusion coefficient of the MPL is only about 21% that of its GDL substrate and Knudsen diffusion accounts for 80% of the effective diffusion coefficient of the GDL with MPL measured in this study. No existing correlations can correlate the effective diffusion coefficient with significant Knudsen contribution.en
dc.publisherUniversity of Waterlooen
dc.subjectEffective Diffusion Coefficienten
dc.subjectMicroporous Layeren
dc.subjectGas Diffusion Layeren
dc.subjectKnudsen Effecten
dc.subjectLoschmidt Cellen
dc.subjectPEM Fuel Cellen
dc.subjectMass Transporten
dc.titleExperimental Measurement of Effective Diffusion Coefficient in Gas Diffusion Layer/Microporous Layer in PEM Fuel Cellsen
dc.typeMaster Thesisen
dc.subject.programMechanical Engineeringen and Mechatronics Engineeringen
uws-etd.degreeMaster of Applied Scienceen

Files in this item


This item appears in the following Collection(s)

Show simple item record


University of Waterloo Library
200 University Avenue West
Waterloo, Ontario, Canada N2L 3G1
519 888 4883

All items in UWSpace are protected by copyright, with all rights reserved.

DSpace software

Service outages