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Comparative Calibration of Heat Flux Sensors in Two Blackbody Facilities.


pdf icon Comparative Calibration of Heat Flux Sensors in Two Blackbody Facilities. (175 K)
Murthy, A. V.; Tsai, B. K.; Saunders, R. D.

NIST SP 971; August 2001.

NIST SP 971: "Collected Reports and Publications by the National Institute of Standards and Technology on Heat Flux Gage Calibration and Usage.", 2001.

Journal of Research of the National Institute of Standards and Technology, Vol. 104, No. 5, 487-494, September/October 1999.

Available from:

For More Information on NIST SP 971 visit: WEBSITE: http://www.bfrl.nist.gov/866/heatflux/index.htm

Keywords:

heat flux; sensors; black body; calibration; irradiance; transfer calibration

Abstract:

This paper presents the results of heat flux sensor calibrations in two blackbody facilities: the 25 mm variable temperature blackbody (VTBB) primary facility and a recently developed 51 mm aperture spherical blackbody (SPBB) facility. Three Schmidt-Boelter gages and a Gardon gage were calibrated with reference to an electrical substitution radiometer in the VTBB. One of the Schmidt-Boelter gates thus calibrated was used as a reference standard to calibrate other gages in the SPBB. comparison of the Schmidt-Boelter gages calibrations in the SPBB and the VTBB agreed within the measurement uncertainties. For the Gardon gage, the measured responsivity in the SPBB showed a gradual decrease with increasing distance from the aperture. When the gage was located close to the aperture, a distance less than the aperture radius, the responsivity in the SPBB agreed with VTBB measurements. At a distance of about three times the aperture radius, the responsivity showed a decrease of about 4%. This is probably due to higher convection loss from the Gardon gage surface compared to the Schmidt-Boelter sensor.