Work

Numerical study on the effects of humidity on parallel-rod dielectric barrier discharge in atmospheric air

Year: 2025

Type: article

Abstract: In this study, the impacts of humidity on a parallel-rod dielectric barrier discharge (DBD) in atmospheric humid air were numerically examined. Electron transport parameters across varying humidity levels were determined using the Boltzmann equation solver. The modulation effects of photoionization, dielectric permittivity, and secondary emission coefficient on the discharge characteristics under varying humidity levels were analyzed. For all studied conditions, higher humidity delays the streamer onset and reduces the streamer velocity and electron density. The streamer radius was found to initially increase and then decrease during propagation as humidity increases, a phenomenon attributed to the lateral distribution characteristics of the net ionization rate. For a typical condition, the streamer breakdown voltage increases linearly with humidity, with the breakdown field rising by approximately 1% at 100% relative humidity (RH) compared to 0% RH (at 300 K). Photoionization can advance the streamer onset and accelerate its propagation but has little influence on the breakdown voltage, and the impacts of humidity remain consistent with or without photoionization. A higher dielectric permittivity (εr = 4.2–8) can mitigate the impact of humidity, which is attributed to the decreased relative difference in the effective ionization coefficient (αeff) between high- and low-humidity conditions. The influence of humidity is slightly less significant as the secondary electron emission coefficient (γ) increases, primarily attributed to the enhancement of αeff under a higher γ. The above findings provide deeper insights into how humidity regulates streamer dynamics in DBD systems.

Source: Physics of Plasmas

DOI: 10.1063/5.0264687