High Heat-Flux Sensor Calibration: A Monte Carlo Modeling

Abstract

Conventional calibration of heat-flux sensors uses high-temperature blackbody radiation and places the sensors away from the blackbody aperture. This approach limits the achievable calibration heat flux to about 50 kW/m 2 . Recent interest in extension of the calibration to higher heat-flux levels requires placement the sensors inside the heated cavity under nearly hemispherical irradiation environment. The incident flux at the sensor location depends on the effective emissivity, which is a function of the combined cavity and sensor geometry, and the properties of the radiating surfaces. A scheme is presented to compute the effective emissivity for such measurement schemes by the use of the Monte Carlo technique. Typical results presented demonstrate the influence of the cavity wall surface emissivity and diffusity, nonuniform temperature distributions, and the sensor location on the calculated effective emissivity