Effect of cathode model on arc attachment for short high-intensity arc on a refractory cathode
Artikel i vetenskaplig tidskrift, 2016

Various models coupling the refractory cathode, the cathode sheath and the arc at atmospheric pressure exist. They assume a homogeneous cathode with a uniform physical state, and differ by the cathode layer and the plasma arc model. However even the most advanced of these models still fail in predicting the extent of the arc attachment when applied to short high-intensity arcs such as gas tungsten arcs. Cathodes operating in these conditions present a non-uniform physical state. A model taking into account the first level of this non-homogeneity is proposed based on physical criteria. Calculations are done for 5 mm argon arcs with a thoriated tungsten cathode. The results obtained show that radiative heating and cooling of the cathode surface are of the same order. They also show that cathode inhomogeneity has a significant effect on the arc attachment, the arc temperature and pressure. When changing the arc current (100 A, 200 A) the proposed model allows predicting trends observed experimentally that cannot be captured by the homogeneous cathode model unless restricting a priori the size of the arc attachment. The cathode physics is thus an important element to include to obtain a comprehensive and predictive arc model.

gas tungsten arc

electron emission

thermal plasma

modelling

arc attachment

activated tungsten cathode

Författare

Alireza Javidi-Shirvan

Chalmers, Tillämpad mekanik, Strömningslära

Isabelle Choquet

Högskolan Väst

Håkan Nilsson

Chalmers, Tillämpad mekanik, Strömningslära

Journal of Physics D: Applied Physics

0022-3727 (ISSN)

Vol. 49 Article No 485201 -

Drivkrafter

Hållbar utveckling

Styrkeområden

Produktion

Ämneskategorier

Bearbetnings-, yt- och fogningsteknik

Strömningsmekanik och akustik

DOI

10.1088/0022-3727/49/48/485201