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Effect of water on hydrogen permeability
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Tomazic, William A. Hulligan, David |
| Copyright Year | 1987 |
| Description | Doping of hydrogen with CO and CO2 was developed to reduce hydrogen permeation in Stirling engines by forming a low permeability oxide coating on the inner surface of the heater head tubes. Although doping worked well, under certain circumstances the protective oxide could be chemically reduced by the hydrogen in the engine. Some oxygen is required in the hydrogen to prevent reduction. Eventually, all the oxygen in the hydrogen gas - whatever its source - shows up as water. This is the result of hydrogen reducing the CO, CO2, or the protective inner surface oxides. This water can condense in the engine system under the right conditions. If the concentration of water vapor is reduced to a low enough level, the hydrogen can chemically reduce the oxide coating, resulting in an increase in permeability. This work was done to define the minimum water content required to avoid this reduction in the oxide coating. The results of this testing show that a minimum of approximately 750 ppm water is required to prevent an increase in permeability of CG-27, a high temperature metal alloy selected for Stirling engine heater tubes. |
| File Size | 2621743 |
| Page Count | 25 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19870007231 |
| Archival Resource Key | ark:/13960/t4xh4h03m |
| Language | English |
| Publisher Date | 1987-01-01 |
| Access Restriction | Open |
| Subject Keyword | Urban Technology And Transportation Oxygen Stirling Cycle Hydrogen Permeability Stirling Engines Oxidation-reduction Reactions Water Vapor Protective Coatings Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
