Comparative Calibration of Heat Flux Sensors in Two Blackbody Facilities.
Comparative Calibration of Heat Flux Sensors in Two
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,
Available from:For More Information on NIST SP 971 visit: WEBSITE:
heat flux; sensors; black body; calibration; irradiance;
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.