Experimental Study On Load Characteristics Of Atmospheric Pressure Dielectric Barrier Discharge

Compared with commonly used dielectric materials such as glass,quartz and ceramics,polyethylene terephthalate has longer charge storage capacity.This special property of PET(polyethylene teraphtalate)medium can lead to stable atmospheric glow discharge.Therefore,atmospheric pressure PET dielectric barrier discharge has attracted the attention of scholars in China and abroad.In the study of PET DBD,the discharge capacitance closely related to the discharge power(an important parameter describing the discharge characteristics of DBD)(the basis for calculating the important parameters such as air gap voltage,conduction current and air gap breakdown field strength)is also an important issue that scholars pay attention to.In this thesis,the discharge characteristics and plasma discharge capacitance of PET DBD are studied as follows:The effect of power supply frequency on DBD discharge characteristics of atmospheric pressure helium-argon mixture PET was studied.It is found that as the power frequency increases from 7.25 k Hz to 18.84 k Hz,The number of current pulses decreased from 4 to 1,The current pulse amplitude increased from 0.746×10^-2m A to 2.135×10^-2m A.Current pulse amplitude increased by about 286%,Electronic density almost unchanged.At different power frequencies,PET DBD has isolated filament discharge,filament-uniform discharge coexistence and uniform discharge mode.The characteristic regions of three discharge modes are obtained.The effects of electrode voltage and discharge gas on discharge capacitance of PET and Al₂O₃DBD were studied.The following rules are obtained:1.Dielectric materials have little effect on discharge capacitance(including electrode capacitance C,dielectric capacitance C_sdand air gap capacitance C_gas);2.Helium discharge capacitance is greater than argon discharge capacitance;3.With the increase of electrode voltage,the discharge capacitance of helium increases gently,while the discharge capacitance of argon shows the change characteristics of almost constant–sudden increase–slow increase.In order to explain the above changes,the absorption power and electron density of PET and Al₂O₃DBD were calculated by Lisajous figure method and Stark broadening method,respectively.The calculated absorption power and electron density have the following characteristics:1.The absorption power of Al₂O₃DBD is greater than that of PET DBD;2.With the increase of electrode voltage,the absorption power of helium discharge increases almost linearly,while the absorption power of argon discharge shows a change rule of almost constant–rapid increase–slow increase.3.The electron density of PET or Al₂O₃DBD is 10¹⁴cm^-3,almost unchanged with the electrode voltage and increased with the argon content.By analyzing the change of electron density and DBD discharge capacitance,it is known that the increase of DBD electron density will lead to the decrease of DBD discharge capacitance.