Modelling the heating and erosion of a non-refractory cathode in a plasma torch
DOI:
https://doi.org/10.14311/ppt.2025.2.170Keywords:
arc plasma torch, cathode spot, heat conduction, erosion of surface electrode, erosion rate, cathode spotsAbstract
In this work, we study the heating of a hollow cylindrical copper electrode subjected to a rotating arc root modeled by a moving heat flux profile. The problem is solved analytically using a two time scale analysis. In accordance with previous literature works, it is shown that, whenever using reasonable values for the heat flux below the arc root, the fusion temperature of the material is not reached. We explain the experimentally evidenced erosion by the existence within the arc root, at smaller length scales, of cathode microspots. The cathode spot model presented in this paper gives orders of magnitude for the erosion rate in agreement with experiments.
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