Experimental study on characteristics of direct-current laminar-flow nitrogen plasma-jet

Aiming at providing new experimental results on the characteristics of the nitrogen laminar plasma jet, experiments were carried out with the laminar plasma jet generated by a self-developed direct-current (DC) non-transfer plasma generator. The experimental results show that the plasma jet, generated by the plasma generator using nitrogen as the working gas, presents a characteristics of high voltage and low current. Such characteristics are helpful for improving the electrodes lifespan of the plasma generator. As the arc current and gas flow rate increase, the length of the plasma jet varies from short to long, and then from long to short. As the length of plasma jet decreases, the morphology of plasma jet changes from relatively concentrated, axisymmetric and stable state to a scattered, non-axisymmetric and unstable state. In other words, the plasma jet changes from laminar to turbulent state. In addition, the noise from the plasma jet gradually increases during this process