Abstract
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An accurate description of the direct current (DC) plasma torch using different carriers gases at atmospheric pressure is presented to provide operating conditions allowing an optimal design of plasma torch. A computational fluid dynamic (CFD) model was performed to simulate fluid flow in plasma torch. Two‑dimensional electro-thermodynamic distribution of electric, fluid flow, and heat transfer parameters in air plasma torch were implemented to examine the impact of the magnetic coupling on the electric arc. A parametric study of different torch geometries and operating conditions was discussed in order to optimize maximum advance in process stability, rate and deposition efficiency. Important results were achieved, showing that different arc lengths are observed by using different carrier gases. It is confirmed that a low current, a high-voltage DC, a low mass flow rate, and an intense swirl flow are responsible for maintaining the stable arc. In addition, axial velocity of fluid flow increases when reducing the inlet radius of the plasma torch and the arc attachment position is pushed to a longer distance with prolongated anode.