Numerical Study Of Atmospheric Pressure Plasma Jet Based On Multi-field Coupling Calculation

Atmospheric pressure plasma jets have attracted considerable interest due to their low-temperature and easily controlled features since developed in 1990 s.Not only in traditional material processing and surface treatment,but also in burgeoning plasma medicine and environmental engineering,plasma jets have shown unique technical advantages and favorable application prospects.In order to cover larger area for industrial application,the spatially extended atmospheric plasma arrays are constructed by many densely packed plasma jets.Thus,it is a question of how to get better homogeneity.To study this,this work start with one-tube plasma jet and expand to two-tube plasma jets to research the interactions.We use a two-dimensional unsteady multi-field code.Through solving the continuity equations of species,the electronic energy equation,the momentum equation and the energy equation of the flow field,Poisson equation,we simulate the generation and development of plasma jets and analysis the temporal and spatial evolutions of key parameters.The key influencing factors of plasma jet are studied from single channel plasma jet.Considering the stability of plasma properties,atmospheric pressure helium discharge is commonly used in practical applications.The pressure of helium is slightly higher to ensure that the helium discharge area is large enough to be unacted on the external air composition(especially oxygen)in the open air.Numerical simulation results show that the transition area between helium and air can produce a large number of electron and form a ring-shaped structure because of the Penning ionization and photoionization effect.In order to combine the practical application,the uniformity of the distribution of species downstream is studied,especially that of species(such as oxygen atoms)which are of great importance to the application.On this basis,the interaction between two-tube plasma jets(including coulomb action,flow field action,photoionization effect)is further studied.When air inflow is injected between the two-tube plasma jets,it is found that the two channels can be merged.However,when helium is injected,Penning effect and photoionization effect will be weakened,leading to decreased plasma density.It can be seen from the distribution of species downstream that two-channel plasma jet is not simply two channels overlaid,but has interaction.