Thermal Effect and Hydrodynamic Perturbation in a Coplanar Nanosecond Pulse Periodic Surface Dielectric Barrier Discharge

The thermal effect and hydrodynamic perturbation within a high-frequency pulse-periodic nanosecond coplanar surface dielectric barrier discharge (ncSDBD), are studied experimentally and numerically. The discharge is initiated in a coplanar open electrodes arrangement with 10 mm inter-electrode gap for pulse repetition frequencies (PRF) between 10 and 100 kHz. The discharge morphology, heat release, ozone distribution and refractive index perturbation with different repetition frequency are measured by intensified charge-coupled device (ICCD) imaging, spatially resolved emission spectroscopy, optical absorption methods and the background-oriented schlieren technique, respectively. With the increase of frequency and number of pulses, the discharge morphology changes from quasi-uniform structure at 10 kHz to filamentary mode, and a higher gas temperature is observed near the grounded electrode. In turn, the gas heating largely determines the dynamics of ozone. The discharge characteristics and hydrodynamic perturbation are modelled and analysed numerically. The existence of the exposed grounded electrode facilitates the connection between the positive and negative discharges. During the afterglow phase, a large amount of positive charge accumulates near the two exposed electrodes due to charge separation, resulting in a strong body force, which triggers the blowing up of the flow.