This paper deals with the feasibility of performing primary calibration of heat-flux sensors at high irradiance levels by placing inside the cylindrical cavity of a graphite-tube blackbody. The experimental study comprised of measurements on two Schmidt-Boelter sensors, 200 kW m-2 and 500 kW m-2 range respectively. To provide a baseline comparison, the sensors were first calibrated using the transfer technique with reference to an electrical substitution radiometer in the range 0 to 50 kW m-2. In-cavity calibration experiments, covering the full range of the sensors, comprised of determining the optimum location for the sensor inside the cavity and measurements over a range of temperatures from 800 C to 1450 C. These experimental results for the radiance distribution along the cavity axis demonstrated the predictions of the Monte Carlo simulation that the optimum location for the sensor is about one cavity radius from the base. Factors influencing the in-cavity calibrations and the associated correction for the effective emissivity are presented. The responsivity values for the two sensors obtained from the transfer technique and the in-cavity agreed favorably within the experimental uncertainty. The good agreement suggests the application of the in-cavity technique for primary calibration at high heat-flux levels, and further development for flux levels higher than 500 kW m-2.
Proceedings Title: 38th| AIAA Thermophysics Conference| AIAA Journal of Thermophysics and Heat TransferandThermophysics Conference and AIAA Journal of Thermophysics and Heat Transfer
Conference Dates: June 6-9, 2005
Conference Location: Ontario, CA
Conference Title: AIAA Journal
Pub Type: Conferences
blackbody, heat-flux sensors, in-cavity calibration