Numerical Analysis of the Influence of Atmospheric Plasma Gun Structure on Plasma Flow

To investigate the gun structure influence on gas flow characteristics during plasma spraying process, a simplified 3-D computing model was developed to calculate the multi-physical properties of the gun. The geometric model included cathode and anode, and electrodes boundary layers. Besides the temperature of ions and electrons was treated separately. In other words, the model used a two-temperature plasma model, which took into account ionization and recombination reactions of ions and electrons, the plasma flow inside the spray gun was studied. From the calculation results, decreasing of gun throat diameter caused the increase of velocity and decreasing of temperature. The change of velocity behaved a linear relationship with diameters, while temperature decreasing slowed down when the diameters reached a certain value. The research will provide theoretical guidance for the optimal design of spray gun. (paper)