Study On The Structural Optimization And Power Supply Of A Surface Dielectric Barrier Discharge Device

Surface Dielectric Barrier Discharge (SDBD) can produce low temperature plasma at atmospheric pressure, which is in large area and has high energy density. SDBD has been widely studied in the field of biomedicine, surface modification of materials, environmental protection, etc. The structure and power supply of a SDBD device is the main factors that affect plasma temperature and density, the electron energy distribution and the formation of reactive species. Research on the optimized structure and its power supply of a SDBD device plays a great guiding role in improving its application efficiency. A SDBD device is designed in this paper, in which the high voltage electrode is made of a stainless steel spring close to the inner wall of a dielectric tube. The dielectric tube packaged by an aluminum foil is used as the low voltage electrode. This paper focused on optimization of the structure of a SDBD device and its power supply. A simulation of the electrostatic field in the SDBD device is conducted by Ansoft Maxwell software, guiding the structural design of a discharge device in theory. In addition, the influence of the high voltage electrode configuration, power supply and dielectric on the discharge characteristics and ozone generation of the device is experimentally studied under a fixed length of the high voltage electrode. The results are as follows:(1) The electric field increases linearly as the applied voltage increase in the same position of air gap. The electric field increases with the relative permittivity of the dielectric tube, and decreases with the thickness of the dielectric. Decreasing the diameter of the high voltage electrode and the thickness of dielectric, increasing the the relative permittivity are favorable for reducing the discharge inception voltage.(2) When the high voltage electrode being in a certain length, the pitch is the main factor affecting the discharge characteristics and ozone generation. The wire diameter and tube inner diameter have little influence on the discharge characteristics and ozone generation; At a certain voltage, there exists an optimum pitch that makes discharge power to reach the maximum. When the pitch is larger than the optimum pitch, the discharge power is almost the same. At the same applied voltage, the discharge intensity decreases with an increase in the thickness of dielectric, and when the discharge power decreases, the amount of ozone and ozone yield (namely, the amount of produced ozone per unit of energy) reduces. While the discharge intensity, discharge power and ozone production enhances with the relative permittivity of the dielectric tube, and increase.(3) When an AC power is supplied on the SDBD device, there is a peak voltage that makes the ozone yield reach the maximum. Experimental comparison of different power frequency shows that the SDBD device excited by AC power supply of 9.6kHz can obtain a higher discharge power and ozone generation at a low applied voltage. The discharge intensity is weaker but the area of plasma layer is larger when the device is excited by AC power supply of 50Hz.