Numerical investigation on the effects of discharge conditions on a nanosecond pulsed surface dielectric barrier discharge

In order to understand the impacts of discharge conditions on the discharge characteristics of a nanosecond pulsed surface dielectric barrier discharge, the effects of gas pressure, temperature, and velocity are numerically investigated by using a three-equation drift-diffusion model with a 4-species 4-reaction air chemistry. The scaling laws of plasma morphology and gas heating on pressure are obtained for further reduced modeling in the flow-control application. Theoretical discussions on the scaling laws are carefully conducted. When the pressure increases in the studied range, while the temperature is fixed, the streamer propagating velocity (V), the plasma sheath thickness (h), the maximum streamer length (L), the total discharge energy (QD_ei), and the gas heating (QGH) decrease. The plasma morphology and the gas heating have different scalings on the pressure according to V∼ep, h∼p−0.8, L∼p−0.8, QD_ei∼p−0.5, and QGH∼p−0.5. When the temperature decreases in the investigated range, while the pressure is kept constant, V, h, L, QD_ei, and QGH also decrease. When the gas velocity increases from 0m/s to 258m/s, while the pressure and the temperature are kept fixed, V and h increase. The total QD_ei and QGH increase by 4.3% and 4.6%, respectively. It is concluded that, on the one hand, the discharge characteristics are mainly dominated by the gas number density, which can be equivalently changed by the gas pressure and temperature. On the other hand, when the gas pressure and temperature are kept constant, the uniform gas velocity has weak effects on the discharge characteristics.