Transient temperature distributions in cylindrical arc columns following abrupt current changes

TLDR: In this article, the importance of natural radial flow under transient conditions has been estimated by calculating flow velocity profiles from the measured temperature distributions and published gas density data, and show the increasing importance of the radial flow at higher currents.

Abstract: Using the shock wave technique, radial distributions of gas temperature have been measured in cylindrical, wall stabilized, arc columns under both steady state and transient conditions. The arc atmosphere was air and the current range 0?5-100 A. The transient measurements included the case of free recovery following sudden current interruption. The temperature profiles have been used in conjunction with published electrical conductivity data to determine electrical conductance values and these show good agreement with direct electrical measurements and theory. This result confirms that the arc plasma is in approximate thermal equilibrium so that the column behaviour may be described solely in terms of thermal processes. The importance of natural radial flow under transient conditions has been estimated by calculating flow velocity profiles from the measured temperature distributions and published gas density data. The results are in good agreement with theory, and show the increasing importance of the radial flow at higher currents.