Avtomaticheskaya Svarka (Automatic Welding), # 5, 2019, pp.6-17
Effect of current and arc length on characteristics of arc discharge in non-consumable electrode welding
I.V. Krivtsun, V.F. Demchenko, I.V. Krikent, D.V. Kovalenko, I.V. Kovalenko
E.O. Paton Electric Welding Institute of the NAS of Ukraine, 11 Kazimir Malevich Str., 03150, Kyiv, Ukraine.
A method of mathematical modelling was used for investigation of effect of current intensity and length of argon atmospheric-pressure arc with refractory (tungsten) cathode on heat, electromagnetic and gas-dynamic characteristics of arc plasma, including the characteristics of its thermal, electric and dynamic (force) effect on anode surface. A short review of the mathematical models used for this purpose is given. The temperature fields and patterns of current flow in the arc column are illustrated with corresponding isotherms and current lines. Analysis of force effect of arc current on its column plasma is based on calculation data on distribution of magnetic pressure in arc plasma and corresponding magnetic force acting on plasma. Peculiarities of distribution of total pressure and rate of plasma movement in the arc column are also analyzed. The calculation data are given on distributions of density of electric current and heat flux on the surface of water-cooled and evaporating anode as well as on distribution of plasma potential along the boundary of anode layer depending on current intensity and arc length. The concepts of effective values of anode and cathode potential drop are implemented. Following from the calculation value of heat flux into anode and experimental watt-ampere characteristic of argon-arc with refractory cathode the data were obtained on value of net efficiency of such an arc in current range 50-300 A for arcs of 1.5; 2 and 3 mm length. Dependence of dimensions of current channel and zone of thermal effect of arc to anode on current and arc length was determined. 26 Ref., 22 Fig.
Keywords: arc with refractory cathode, arc current, arc length, arc plasma, arc column, anode layer, current density on anode, heat flux in anode, mathematical modelling
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