THERMAL-DIFFUSION FACTORS OF AN ARGON-HELIUM MIXTURE IN THE HIGH-TEMPERATURE RANGE (2000-4000-K)

In order to develop a new-simple-method for measuring heavy-particles temperatures and their gradients in a laminar plasma flow, thermal diffusion factors values in the high temperature range were required. No thermal diffusion factors measurements have been made over typically 1000 K. Consequently, this paper is concerned with thermal diffusion factors measurements for an argon-helium mixture in the high temperature range from 2000 to 4000 K approx. The experimental results are compared with theoretical calculations namely with the first approximation of Chapman and Cowling to the thermal diffusion factor, and with a new approximation scheme. The experimental data agree well with the theoretical values. Velocity fields have been measured by means of Laser Doppler Anemometry. This recent experimental technique for measuring mean velocities and velocity fluctuations has been here used under adverse high temperature conditions. © 1979.