Calibration of high heat flux sensors at NIST

An ongoing program at the National Institute of Standards and Technology (NIST) is aimed at improving and standardizing heatflux sensor calibration methods.The current calibration needs of U.S. science and industry exceed the current NIST capability of 40 kW/m 2 irradiance.In achieving this goal, as well as meeting lower-level non-radiative heat flux calibration needs of science and industry, three different types of calibration facilities currently are under development at NIST: convection, conduction, and radiation.This paper describes the research activities associated with the NIST Radiation Calibration Facility.Two different techniques, transfer and absolute, are presented.The transfer calibration technique employs a transfer standard calibrated with reference to a radiometric standard for calibrating the sensors using a graphite tube blackbody.Plans for an absolute calibration facility include the use of a spherical blackbody and a cooled aperture and sensor-housing assembly to calibrate the sensors in a low convective environment.