INVESTIGATION OF A RAPID-QUENCH SAMPLING PROBE FOR NONEQUILIBRIUM AIR FLOWS
Abstract
Shock tunnel experiments in air are reported which basically were designed to determine the free-stream composition from the gaseous composition of a captured sample. The sample was obtained with an explosively-sealed probe. Because of the rapid cooling of the captured sample by the probe, it was anticipated that the temperature of the sample would be sufficiently low to result in the conversion of the captured NO to NO2. An attempt was made to infer the NO concentration of the free stream by measuring both the NO2 concentration and the resultant O2 deficiency in the sample. It was found that these measurements were limited by several considerations. Among these were chemisorption of NO2 on the interior of the stainless-steel probe, and an apparent diffusive separation caused by the blunt-nosed probe which was used. These effects were eliminated by conditioning the probe through pretest exposure to NO2 and by adding a conical nose piece to the probe. With these changes it was verified that NO was collected, but it was not possible in the present experiments to obtain a quantitative measurement of the NO2 in the sample. This appeared to be the result of water vapor contamination which reacted with free NO2 and O2 to form HNO3. However, significant O2 deficiencies were found which agreed fairly well with those expected.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1967
- Accession Number
- AD0649328
Entities
People
- F. J. Stoddard
- W. S. Watt
Organizations
- Calspan