Studies of the anode region of a high-intensity argon arc

Abstract

This paper is concerned with experimental and analytical/numerical studies of the anode region of an atmospheric pressure argon arc in a current range from 100 to 300 A. The arc arrangement allows unobstructed viewing of the entire anode region, including the anode itself, and it is also suitable for simulating short as well as long arcs. Depending on the flow situation in the anode region, two different types of stable arc roots are observed. The diffuse anode arc root, characterized by a strong flow impinging on the anode surface, is well known from free-burning, short arcs. The second type reveals a more or less vevere constriction in front of the anode, caused by the entrainment of gas into the arc, resulting in an anode jet. Measurements of the induced flow at the cathode of such an arc show a linear increase of the induced mass flow rate with increasing current. This correlation can be confirmed by a simple analysis. A fast-scanning, computer-controlled system has been used for spectrometric measurements of the temperature distribution for both modes of anode arc roots, assuming local thermodynamic equilibrium (LTE) in the arc. The maximum temperatures in the arc core compare favorably with calculated temperature distributions of the constricted mode. The calculated isotherms, however, show a substantial shift which is probably due to the chosen boundary conditions at the end of the constrictor tube.

Anode Melting From Free-Burning Argon Arcs

“…Previous landmark investigations of arc interaction with the anode, have been made by Sanders et al [1] and Jenista et al [2]. Our investigation corresponds with the "cathode jet dominated" mode, defined in [1], for arcs of a few millimeters in length.…”

Measurement of the amount of liquid and vapour created by an electric arc on an electrode – case of Ag and AgSnO2electrodes

“…-The decrease of the anode static erosion for Ag (by a factor 20) may be linked to the weak plasma/surface interactions when the electrode gap increases and to a change of discharge mode [12][13][14].…”

Vortex Flows Induced by Electric Arc

“…Pressure on anode surface is falling off by 6 times in comparison with diffusive discharge while conductive heat flow into anode practically is not changeable. Unfortunately, during the experiments described in [8] the measurements of velocity value and direction of gas flow were not carried out. But, as numerical analysis has shown, field of temperatures is mostly determined by vortex gas flow.…”

“…we find computed results of short electric arc with a cylindrical cathode nozzle [8] and open-flame arc with a conic cathode [9]. The influence of length and current force on arc characteristics is investigated.…”