Ablation in a high shear environment
| Autor: | Kenneth W. Graves |
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| Rok vydání: | 1966 |
| Předmět: | |
| Zdroj: | AIAA Journal. 4:853-857 |
| ISSN: | 1533-385X 0001-1452 |
| DOI: | 10.2514/3.3557 |
| Popis: | The behavior of ablation materials, under conditions representative of hypersonic velocity at low altitude, was investigated by analysis and experiment. Tests were conducted in the freely expanding jet of the Wave Superheater Test Facility at Cornell Aeronautical Laboratory, using hemisphere-cylinders of teflon, pyrex, quartz, and phenolic refrasil as specimens. The analysis consisted of solutions to existing theoretical melting and vaporizing ablation of glassy materials over a wide range of stagnation-point pressure. In agreement with tests, the analysis yielded a constant effective heat of ablation over the pressure range (15-65 atm). No vaporization of silica occurred at the test enthalpy level (2000 Btu/lb). This is significant to the ablation of phenolic refrasil, which ablated by melting and charring except at stagnation pressures of 40 atm or more where erosion occurred. The contribution of heating due to combustion was revealed by a comparison of ablation in pure nitrogen and pure air both for phenolic refrasil and teflon. The effective heat of ablation for teflon in nitrogen was 1850 Btu/lb as compared to 1250 Btu/lb in air and little change was exhibited over the pressure range. However, teflon ablation was pressure sensitive in a 10% O2 atmosphere because of combustion phenomena. |
| Databáze: | OpenAIRE |
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