Optimization Of Ground Electrode And Research On Characteristics Of Dual-Frequency Capacitively Coupled Power Supply Of Surface DBD Plasma

The surface dielectric barrier discharge has wide application prospect because of the larger plasma area. The structure of ground electrode and the type of power supply attribute to the discharge intensity and the formation of active material. So the key to the research and application of the surface dielectric barrier discharge plasma is the optimization of discharge device structure and power supply. In this paper, the impact and optimization of ground electrode structure are studied in order to enhance the discharge intensity and improve the efficiency of active substances generation. The generation of dual-frequency capacitively coupled plasma under the atmospheric pressure is also studied. The advantages and characteristics of dual-frequency capacitively coupled plasma are obtained by the research of emission spectrum and discharge characteristic. The main conclusions are as follows:(1) For the ground electrode structure of SDBD, the belt-like structure is superior to the traditional surface-like structure. For the belt-like structure, compared with the traditional structure, discharge power is 16% above and active material generation is 61.2% above, at the same time, the produce efficiency is 48.3% above, under the condition that the amplitude of the 50 Hz voltage is 20 kV.(2) For the belt-like structure, paralleled structure is superior to the coincident structure and there exists an optimal electrode gap. For the belt-like structure, under the condition of 17 kV amplitude of 50 Hz voltage, the discharge power of paralleled structure is 11% higher than that of the coincident structure. For the paralleled structure, with the increase of electrode gap, the initial discharge voltage increases and the discharge power increases after decreasing, at the same time, the generation of active material inside pipe decreases after increasing, but the generation of active material outside pipe is rising. The optimal electrode gap is 6 mm. Under the condition of 20 kV amplitude of 50Hz voltage, total amount of active material generated is the highest and 10% higher than the other gap.(3) The effect of high frequency power and low frequency power is different in DF-CCP. And the discharge characteristic is better than that in the single frequency power supply condition. In DF-CCP, the effect of low frequency power on the discharge characteristic is not obvious. However, with increase of the voltage of high frequency power, the spectral intensity and the amount of active substances generated significantly increases, but the active material production efficiency decreases. In the condition of 15kV-LF and 5kV-HF, compare with the single high frequency supply condition, for DF-CCP, the spectral intensity is 50% higher; the amount of active material generated is 26% higher; the active material production efficiency is increased by 150%, but still lower than that of single low frequency supply condition.(4) The discharge characteristics significantly increased after the optimization of the structure of ground electrode and the power supply. Under the condition of 6mm electrode gap,2.5kV-LF and 5kV-HF, for the condition after optimization, the amount of active material generated is 75.2% higher that of single high frequency supply condition before optimization and active substances production efficiency is slightly lower than single low frequency supply condition before optimization. After all, the optimization effect is obvious.