- Author
-
Gokoglu, S. A.
- Title
- Precise Calibration Technique for Measuring High Gas Temperatures. BFRL Fire Research Seminar. VHS Video.
- Coporate
- NASA John H. Glenn Research Center at Lewis Field, Cleveland, OH
- Report
-
Video
September 21, 1999
- Keywords
-
gas temperature
- Abstract
- Due to technical difficulties the last 20-30 minutes of the seminar is missing. Only have first 35 minutes. A technique was developed for direct measurements of gas temperatures in the range of 2050K - 2700K with improved accuracy and reproducibility. The technique utilized the low-emittance of certain pure, metal-oxide fibers whose diameters varied from 60 - 400m in the experiments. The uncertainty of the technique was limited by the uncertainty in the melting points of the materials, i.e., +15K. The abrupt increase in the emittance of the fibers upon melting was utilized as indication of reaching a known gas temperature. The accuracy of the technique was confirmed by both the fiber-diameter independence of the results and by the calculated low emittance values of transparent fibers, of order 0.01 at a few degrees below their melting point. This melting-point temperature was approached by increments smaller than 4K, accomplished by controlled increases of reactant flow rates in H2/air or H2/O2 flames. As applications, the technique was used (a) for assessing the uncertainty in thermocouple measurements for inferring gas temperatures, and (b) for calibrating an IR camera to measure gas temperatures, thereby demonstrating its capability as an excellent calibration reference.