Measurement of thermal conductivity of argon-nitrogen gas mixtures at high temperatures†

Abstract

The temperature profiles in wall-stabilized atmospheric pressure arcs in argon, nitrogen and argon-nitrogen mixtures have been obtained at currents of 26 A and 30 A using spectroscopic techniques. The temperature profiles were measured using both the absolute intensity of spectral lines and the absolute intensity of the continuum radiation. Good agreement between the two methods is found in argon but there is a considerable discrepancy in nitrogen. This is attributed to the existence of a N- ion. The temperature profiles and previously measured potential gradients are then used in conjunction with calculated values of the electrical conductivity to obtain the thermal conductivity of several argon-nitrogen mixtures. The results obtained are in good agreement with previously published data for the pure gases and show the gradual formation of an arc core and the increase in axis temperature as the gas mixture is varied from pure argon to pure nitrogen. Another result of these investigations is to show the im...