Dielectric barrier discharge non-thermal plasma stability analysis based on temperature profiles using fiber bragg grating sensor

Abstract

This study aims to determine the stability of atmospheric pressure non-thermal plasma generated in dielectric barrier discharge (DBD) based on temperature profiles measured using a fiber Bragg grating (FBG). Two sets of the DBD reactor were fabricated using two symmetrical electrodes separated by 2.31 mm and 3.74 mm discharge gap, respectively with dielectric material of alumina plates. The FBG was used as a temperature sensor by embedded directly into the plasma stream. The temperature was measured at different applied voltages within range of 0 to 7 kV. The results show that the streamer discharge was generated by the DBD reactor with the 2.31 mm discharge gap at 5.5 kV while the DBD reactor with the 3.74 mm discharge gap generated filamentary discharge at 7 kV. The temperature increases proportionally as the applied voltages increases. The stability of the DBD reactor was performed by operated at constant applied voltage for 600 seconds. The temperature profiles of the DBD reactor with the 2.31 mm discharge gap were measured in the range of 210 - 231 oC with applied voltage of 5.0 kV and in the range of 270 - 286 oC at 6 kV. For the DBD reactor with the 3.74 mm discharge gap, the temperature profiles were measured in the range of 47 - 67 oC when operated at 6 kV and in the range of 193 - 245 oC at 7 kV. A huge temperature difference was found for the DBD reactor with the 3.74 mm discharge gap which results in localized heat generation of the discharge caused by the filamentary discharge. The filamentary discharge disrupted the homogeneity of the plasma and created the instabilities in the DBD reactor. The plasma intensity of the DBD reactor measured by the optical emission spectroscopy (OES) showed more fluctuation pattern when the filamentary discharge was generated compared to the streamer discharge. From this finding, the FBG can be used for temperature profiles of the DBD reactor to determine its stability on the generation of the filamentary discharge.