Experimental and simulation research on the influence of gas flow rate on Ar APPJ

The influence of gas flow rate on Ar atmospheric pressure plasma jet (APPJ) was experimentally researched. Furthermore, the distributions of velocity and concentration of Ar flow in ambient air were simulated numerically by a two-dimensional axis-symmetrical model of plasma jet. The continuity equation, N-S equations, K-ε turbulence equation and species transport equation of mixture gas were coupled together and solved. The experimental results show that, the Ar APPJ with the variation of gas flow rate can be divided into three patterns: laminar flow, transition status, and turbulent flow. The APPJ length is longest under transition status. The numerical simulation results reveal that, when the flow is laminar, the radial Ar velocity and molar concentration of APPJ components begin to increase, which agrees with experimental results that the APPJ length is lengthened with the increment of flow rates. When the flow is turbulent, the radial diffusion of Ar rises suddenly and the molar concentration of APPJ head decreases, which is also consistent with the observed experimental phenomena that the jet length turns to short at a high Ar flow rate.