Calorimetric Probe for the Measurement of Extremely High Temperatures

A water-cooled gas sampling probe capable of steady-state operation at 15 000°K and one atmosphere has been developed. Temperature is measured by a calorimetric technique which can provide high-accuracy calibration under arcjet conditions. The probe also measures velocity and chemical composition and, because of its small size (∼⅛ in. o.d.), is capable of accurate local measurements in the presence of severe gas-stream property gradients. Calibrations in the partially ionized argon-helium environment of an arcjet exhaust indicated an average agreement with mass and energy balance criteria within ½%, and a standard deviation from the mean of less than 3%.