Study Of The Narrow Discharge Gap DBD Plasma Source At Atmospheric Pressure And Its Basic Applications

Some scientists have predicted that the age of low temperature plasma will come following the age of nanometer science and technology, owing to its tremendous applications in industry. The dielectric barrier discharge (DBD), as an effective method of producing non-equilibrium plasma, has been paid much attention to in recent years due to its prospective applications in plasma chemical engineering, material surface modification, preparation of nanometer material, environmental protection and so on.There are many unsolved problems in conventional DBD gas ionization technique, resulting in lower gas ionizability, which cannot be used in non-equilibrium plasma chemistry. In order to increase the gas ionizability and generate strong ionization discharge in large volume at atmospheric pressure, the narrow discharge gap DBD is proposed in this dissertation. Based on"Studies on the Ionization of Gas Molecule Using Ultra-Strong Electrical Field Discharge and Its Applications"(No: 69871002) supported by National Natural Science Foundation of China, discharge characteristics of the narrow discharge gap DBD, dielectric material properties, diagnosis method and its applications are mainly studied in this dissertation. The formation and evolvement of the narrow discharge gap DBD plasma are explained, and many problems in designing and application of DBD plasma source are solved in this work.Theory reasoning and experimental results show that the q-v figure is not only to diagnose the discharge power but also to other discharge parameters of DBD plasma. The improved high-voltage electric bridge method is another accurate and convenient method to measure DBD plasma discharge power, owing to that it can effectively eliminate the effect of equivalent capacitance in discharge gap.Three methods, including the narrow discharge gap and thinner dielectric layer replacing the wide discharge gap in conventional DBD, high-frequency high-voltage power supply replacing 50Hz high-voltage power supply, Al₂O₃ porcelain above 95% purity replacing ordinary borosilicate glass, were used in the narrow discharge gap DBD plasma source at atmospheric pressure. These improvements are very helpful in increasing the electrical filed strength and ionization region in discharge gap of DBD. As a result, strong ionization discharge is accomplished at atmosphere pressure. The reduced field of equivalent in discharge gap reaches more than 200×10^-17V·cm², the average electron energy is 10¹6eV, the electron density exceeds 10×10²³/m³, the largest density of input power reaches 2.5W/cm², which are much higher than those in conventional DBD.