Determination of the recombination efficiency of thermal control coatings for hypersonic vehicles
- National Aeronautics and Space Administration, Langley Research Center, Hampton, VA (United States)
A method is presented for determining the recombination efficiency of coatings for hypersonic vehicle applications. The approach uses experimental results from arc-jet tests with an analysis to determine the efficiency for the recombination of atomic species present in the boundary layer. The analysis employs analytical solutions to the laminar boundary-layer heat-transfer equations with experimental heating-rate, temperature, and pressure measurements. The authors discuss experimental difficulties in achieving reliable materials-performance data. The utility of the method is that it provides a rapid and efficient tool for use in qualitative screening and development of materials. The effects of second-order heat-transfer terms may be as high as 50% for low-catalysis surfaces. With the second-order terms included, the maximum uncertainty in recombination-efficiency data for low-catalysis surfaces is 45%. The discussions are based on experimental data and calculations for arc-jet tests of the titanium alloy Ti-14Al-21Nb with a borosilicate-like glass coating that has a recombination efficiency of about 0.006 to 0.01. 20 refs.
- Research Organization:
- NASA Langley Research Center, Hampton, VA (United States)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 57417
- Journal Information:
- Journal of Spacecraft and Rockets, Vol. 32, Issue 1; Other Information: PBD: Jan 1995
- Country of Publication:
- United States
- Language:
- English
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