Increasing μDMFC efficiency by passive CO2bubble removal and discontinuous operation
| Autor: | Steffen Eccarius, Peter Koltay, Christian Litterst, Roland Zengerle, C Hebling |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Materials science
business.industry Capillary action Mechanical Engineering Bubble Microfluidics Tapering Mechanics Computational fluid dynamics Electronic Optical and Magnetic Materials Cross section (physics) Mechanics of Materials Fluidics Electrical and Electronic Engineering business Methanol fuel Simulation |
| Zdroj: | Journal of Micromechanics and Microengineering. 16:S248-S253 |
| ISSN: | 1361-6439 0960-1317 |
| DOI: | 10.1088/0960-1317/16/9/s12 |
| Popis: | A new concept that enables fully passive CO2 gas bubble removal in micro direct methanol fuel cells (μDMFCs) is presented. The original concept behind the presented degassing structure (flowfield) is based on microchannels with a T-shaped cross section. These channels have defined tapering angles over their cross section (α) and along their axis (β). The tapered channel design creates an intrinsic transport mechanism that removes the gas bubbles from the electrodes by capillary forces only. Computational fluid dynamic (CFD) simulations have been used to determine applicable opening angles of α = 5° and β = 1.5°. The experimental verification was done by using a transparent flowfield to show the passive bubble removal as well as with a fully operational μDMFC. During the operation, the fuel cell delivered an output of up to 8 mW cm−2 without the need for external pumping in short-term measurements. During the long-term measurements, discontinuous pumping showed the highest fuel cell efficiency compared to the continuously pumped fuel supply. |
| Databáze: | OpenAIRE |
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