Study On Optical Diagnostics And Arrays Interaction Of Atmospheric Pressure Plasma Jet

Atmospheric pressure plasma jet produces plasma in an open environment,which makes the treated material not restricted by the electrode structure.It is widely used in mutagenic breeding,food processing,wastewater treatment and other fields.Jet arrays formed by jets arranged in a certain topological structure can effectively expand the plasma processing area and make the large-scale application of plasma jet possible.However,as an ionization wave guided by a gas channel,the propagation path of plasma jet is affected by the distribution of electric field and the state of flow and heat transfer in the channel.The combination of multiple jets makes the space electric field and the state transition of plasma more complex,so it is impossible to guarantee the space homogeneity of plasma.In this paper,radiation spectroscopy and spacetime resolution techniques were combined to observe the spatio-temporal evolution behavior and basic parameters of plasma jet arrays,and to explore the effects of array structure and pulse source parameters on plasma uniformity.The specific contents include the following aspects:To study the diagnostic method and its suitable range of the basic parameters of plasma jet,and further elaborated the influence of the macroelectric field or gas compositions on the characteristics of plasma jet.By comparing the variation of plume pattern with pulse repetition frequency,it is confirmed that the local thermal effect promotes the flow regime transition.the process of molecular vibration-rotatio nal transitions can also be affected by changing the atmosphere composition in the channel.In addition,the macroscopic electron density of the plasma is proportional to the discharge current.The results show that the plasma temperature exerts momentum on the airflow and affects the jet shape.The electron density indirectly reflects the change of electric field intensity in space.The effect of one-dimensional parallel jet array density on plasma uniformity was studied.The effects of overlapping jet fields on the divergence angle and length of the array were observed with three jets arranged in parallel.The results show that the electrostatic repulsion of ionization wave is the main reason for plume divergence,and the state of space flow field makes the array morphology have a short "chaotic " period.The relationship between pulse parameters and plasma uniformity of one-dimensional jet array.The morphologies of jet arrays under 35 combinations of pulse width and pulse repetition frequency was studied,and typical spatial flow patterns were analyzed.The results show that the duty cycle of the pulse affects the charge transport in the plasma channel,and the dispersion of plume is positively correlated with the charge.The partial thermal effect is unbalanced,and the uniformity distribution of the array will be dominated by the plasma gas heating process.The characteristics of coaxial jet arrays and their interaction with materials were studied.Six jet units are arranged radially around a circular axis to study the aggregation of ionization waves and the mechanism of the influence of the intrinsic characteristics of materials on the discharge of jet arrays.The results show that dielectric materials promote the formation of horizontal electric field components and surface ionization waves,while there are high conductivity channels between metal materials and jet.