2D self-consistent modeling of arc–electrode interaction in GTAW using a finite volume method. (12th November 2018)

• Record Type: Journal Article
• Authors: Liang, Peng
• Is Part Of: Journal of physics. Volume 52:Number 3(2019)
• Publication Date: 2018-11-12
• Subjects: plasma sheath -- thermal nonequilibrium -- chemical non-equilibrium -- effective conductivity -- self-consistent modeling; Physics -- Periodicals; 530
• DOI: 10.1088/1361-6463/aaeb0e
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: Steady-state 2D simulation of arc welding with a thoriated tungsten cathode and argon plasma is performed using a finite volume method. It is realized by a self-consistent interaction model that includes a chemical and thermal non-equilibrium description of an arc plasma along with a 1D treatment of a sheath-bulk plasma combination layer represented by the boundary cells attached at the cathode–plasma interface. A series of comparisons with experimental data show that with the local effective value of sheath conductivity the arc current is more constricted at the cathode tip, leading to more realistic plasma temperature and voltage results, while no cut-off parameter is needed, which will otherwise set an artificial cathode emission region in the interaction model. Plasma compositions with equilibrium and non-equilibrium methods are compared, leading to the conclusion that the local maximum of electron number density extends from the axis due to strong convective transport while both net ionization and recombination can appear within the LTE regions.