Abstract No.:
2630

 Title:
Simulation of arc root fluctuation in a DC non-transferred plasma torch with three dimensional modeling

 Authors:
Renzhong Huang / Plasma Giken Co. Ltd., Japan
Hirotaka Fukanuma / Plasma Giken Co. Ltd., Japan
Y. Uesugi/ Kanazawa University,
Y. Tanaka/ Kanazawa University, Japan

 Abstract:
It has been well known that the coating quality of plasma spraying is strongly influenced by instability of jets in plasma spray due to the arc root fluctuation. A three dimensional (3D) unsteady modeling was employed in the research to analyze the arc root fluctuation in a DC non-transferred plasma torch. Numerical calculations on the distribution of gas temperature and velocity in plasma torch were carried out using argon as plasma gas. The electrical current density and potential were also discussed. The results indicate that the fluctuation of arc root in an argon plasma jet is mainly induced by the downstream movement of the arc root on the anode surface, the voltage of arc column drops when a new arc root is formed somewhere upstream of the original attachment. This article represents nature of fluctuation of arc root, also in this paper we will present that the voltage-drop calculated is larger than that measured experimentally based on the hypothesis of local thermodynamic equilibrium.

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