Study On The Characteristics Of Low-temperature Atmospheric Plasma Torch

Low-temperature atmospheric plasma torch is a newly developed plasma technology in recent years.It has a broad application prospect in material modification,environmental improvement and biomedicine,and has been widely concerned by scholars in various fields at home and abroad.There are various excitation modes of low-temperature atmospheric plasma torch.In this paper,a low-temperature atmospheric high-pressure plasma torch and a medium-low temperature atmospheric microwave plasma torch were studied,and the characteristics of the two kinds of low-temperature atmospheric plasma torch were studied and analyzed respectively,including:A low temperature atmospheric high pressure plasma torch was driven,which was driven by a sinusoidal AC high voltage power supply.A low temperature atmospheric high pressure plasma torch generator was developed through dielectric barrier discharge.By changing the plasma excitation conditions,the volt-ampere characteristics of high voltage plasma torch were studied,and the influence of parameters such as voltage,current,system power,working gas,working gas velocity on the stability of plasma jet was analyzed.The main results include: different working gas discharge needs different system power;The voltage on the high voltage electrode increases with the increase of the applied voltage when the gas does not start discharging;When the plasma begins to discharge,the voltage on the high voltage electrode will decrease sharply,and only in the negative half stable discharge;When the low temperature atmospheric high pressure plasma torch stabilizes the plasma jet,the current through the torch tube is only positively correlated with the system power,and the voltage is almost constant;Plasma jet can modify the surface of biological samples.A low temperature atmospheric microwave plasma torch was used to generate a low temperature plasma jet directly excited by microwave in the atmosphere.Using HFSS and CST software,the electromagnetic simulation of the atmospheric low-temperature microwave plasma torch generator was carried out to observe the distribution of electromagnetic field and determine the field intensity at the nozzle of the plasma torch.At the same time,the stability of low-temperature atmospheric plasma torch is effectively improved based on the multi-airflow passage structure.The stable plasma was excited on a low temperature atmospheric microwave plasma torch device,and the effects of microwave input power,gas and gas velocity on the discharge characteristics of the torch were compared and analyzed.The main results include: low-temperature atmospheric microwave plasma jet can be produced when the power is less than 100W;The flow rate of ionized gas has little or no effect on the absorbed power,while the increase of the flow rate of carrier gas blowing the plasma out of the nozzle will lead to the increase of the absorbed power when the plasma ionizes;The absorption power increases with the increase of the incident power;The input power required by microwave to cause gas discharge is within a certain range,but the larger the input power is,the more stable the plasma jet will be.