Particle dynamics and heat transfer under plasma conditions

Abstract

AbstractA study was carried out of the momentum and the heat transfer to fine alumina particles injected into a DC plasma jet. Measurements are reported of particle number flux distribution, particle velocity, and inflight particle surface temperature under different operating conditions. The results show that the particle trajectories and associated particle flux distribution depends to a large extent on the particle injection velocity. The maximum particle velocity and surface temperature are noted, however, to remain close to the centerline of the jet, independent of the particle injection conditions. The maximum surface temperature reached by the particles increases with increasing plasma power and the use of an Ar/H2 plasma gas (17 vol. % H2) compared to that for a pure argon plasma.The particle velocity data are in good agreement with the predictions of a two‐dimensional mathermatical model used for the calculation of the particle trajectories and temperature history. The model predictions, however, agreed only in trend with the measured particle surface temperatures. Deviations between the two could still be observed at large distances from the point of injection of the powder. The computed particle number flux distributions were narrower than the measured profiles, which can be attributed to the fact that the model did not include, at this stage, turbulent particle diffusion effects.