Coupling boundary condition for high-intensity electric arc attached on a non-homogeneous refractory cathode
Journal article, 2018

The boundary coupling high-intensity electric arc and refractory cathode is characterized by three sub-layers: the cathode sheath, the Knudsen layer and the pre-sheath. A self-consistent coupling boundary condition accounting for these three sub-layers is presented; its novel property is to take into account a non-uniform distribution of electron emitters on the surface of the refractory cathode. This non-uniformity is due to cathode non-homogeneity induced by arcing. The computational model is applied to a one-dimensional test case to evaluate the validity of different modeling assumptions. It is also applied coupling a thoriated tungsten cathode with an argon plasma (assumed to be in local thermal equilibrium) to compare the calculation results with uniform and non-uniform distribution of the electron emitters to experimental measurements. The results show that the non-uniformity of the electron emitters’ distribution has a significant effect on the calculated properties. It leads to good agreement with the cathode surface temperature, and with the plasma temperature in the hottest region. Some differences are observed in colder plasma regions, where deviation from local thermal equilibrium is known to occur.

Coupling boundary

Refractory cathode layer

Thermal plasma

Gas tungsten arc


Alireza Javidi-Shirvan

University West

Isabelle Choquet

University West

Håkan Nilsson

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

Hrvoje Jasak

University of Zagreb

Computer Physics Communications

0010-4655 (ISSN)

Vol. 222 31-45

Driving Forces

Sustainable development

Areas of Advance


Subject Categories

Manufacturing, Surface and Joining Technology

Fluid Mechanics and Acoustics



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