Two-phase flow phenomena in fuel cell microchannels
Abstract/Contents
- Abstract
- Proton exchange membrane (PEM) fuel cells show promise as CO2-free energy-conversion devices. Predictions show that reducing the size of the gas delivery channels could improve the efficiency and power density of PEM fuel cells, however the expected benefits of reduced channel sizes have not been realized due to flooding by water generated at the cathode. Channels with small dimensions exhibit an increased propensity toward flooding as surface tension forces become significant when compared with viscous, inertial, and pressure forces. This study characterizes the distinct two-phase flow profiles that result from the interplay of these forces. We investigate fundamental water-gas interactions in silicon channels of various hydraulic diameters and cross-sectional aspect ratios using a high-contrast fluorescent imaging technique. Then, we develop a test structure to study the evolution of two-phase flow structures in a microchannel geometry designed to mimic conditions in a fuel cell channel -- a 60-cm long channel with distributed water introduction through a porous gas diffusion layer (GDL) on one wall. Finally, we present considerations for the implementation of spinning-disk confocal microscopy to provide three-dimensional (3D) visualization of two-phase flow structures which may provide insight into key flow transitions that were observed during high-speed fluorescent flow visualization. By characterizing and modeling two-phase flow in various microchannel geometries and under a large range of flow conditions, these studies provide insight that enables the improved design of microchannels for two-phase flow in fuel cells and other practical devices.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2011 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Steinbrenner, Julie Elizabeth |
|---|---|
| Associated with | Stanford University, Department of Mechanical Engineering |
| Primary advisor | Goodson, Kenneth E, 1967- |
| Thesis advisor | Goodson, Kenneth E, 1967- |
| Thesis advisor | Eaton, John K |
| Thesis advisor | Hidrovo, Carlos |
| Advisor | Eaton, John K |
| Advisor | Hidrovo, Carlos |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Julie Elizabeth Steinbrenner. |
|---|---|
| Note | Submitted to the Department of Mechanical Engineering. |
| Thesis | Ph.D. Stanford University 2011 |
| Location | electronic resource |
Access conditions
- Copyright
- © 2011 by Julie Elizabeth Steinbrenner
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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