The degradation of the electrical contact in a gas insulated switchgear (GIS) is closely related to overheating at the contact. However, the disconnector contact is one of the hot contacts in GIS. Therefore, in this paper, the finite element method was used to solve the three-dimensional multiphysics coupling temperature rise field and flow field in the Single Phase in One Tank (SPIOT) type GIS disconnector under different operating conditions. From the perspective of temperature rise field and flow field, this paper analyzed the temperature rise characteristics under different working conditions and explored the feasibility of the direct application of air, CO2 and C4F7N/CO2 mixed gas to an electrical device. The disconnector temperature rise experiment platform was then built to verify the simulation. The results showed that the temperature rise field and the flow field distribution were similar in four gas environments. SF6 gas had the smallest temperature rise, followed by C4F7N/CO2 mixed gas, and the temperature rise of CO2 and air was relatively large. Therefore, from the perspective of the temperature rise field and flow field, it was feasible to directly apply C4F7N/CO2 mixed gas to an electrical device in order to meet insulation requirements.

Dielectric barrier discharges (DBDs) have shown many advantages for surface treatments in various applications. In a common scenario, the surface to be treated is a dielectric that covers the electrode and acts as part of the discharge circuit, therefore surface properties such as permittivity, conductivity and morphology could affect the discharge dynamics. This remains an active research area. In the present study, systematic investigations are conducted on the discharge mechanism in humid air DBDs with one of the dielectric surfaces being non-planar, and the combined effects of surface morphology, voltage polarity and surface electrical properties are highlighted. A two-dimensional plasma hydrodynamics model was constructed and validated with experimental observations. The results showed that when the non-planar surface acts as the cathode a uniform surface discharge was apt to emerge, consequently leading to a higher and more uniform distribution of reactive species fluences towards the non-planar surface compared with the case when it acts as an anode. In cases with an uneven protrusion height, discharges were preferentially formed on the crests of higher protrusions and tended to inhibit the discharges on the adjacent lower ones. Additionally, the effects of the protrusion’s height and the permittivity and conductivity of the non-planar dielectric are discussed with focus on the discharge dynamics and fluences of reactive species towards the non-planar surface. Noting that the surfaces to be treated in reality are generally non-planar on the spatial scale of millimeters, for example human skin, or micrometers, such as unpolished dielectric surfaces, findings from the present work will contribute to an extended understanding of plasma–surface interactions from the perspective of both physics and applications.

In the arcing process of high-current vacuum arc, the metal particles spattered from the active anode will have a significant influence on the plasma characteristics of the arc column when they entrance the interelectrode area. In this paper, the characteristics of a high-current vacuum arc with metal particle are studied by modeling and simulation. The results show that the vapor produced by metal particle will obviously cool the arc plasma and reduce the current density in the vicinity area of the metal particle. In addition, the metal particle will hinder the movement of the cathodic plasma and complicate the ion density distribution and movement process near the metal particle. Finally, an obvious ionization layer will be formed around the metal particle. When the metal vapor passes through the ionization layer, the vapor will be ionized rapidly, and an abundance of ions will be produced at the same time. The research results are of great significance for the deep understanding of arcing process of high-current vacuum arc.

Non-thermal plasma catalysis is a promising way to achieve high efficiency in applications such as energy conversion and chemical engineering. Although synergistic effects between plasmas and catalysts have been preliminarily considered as an underlying mechanism of this type of catalysis, the formation of discharges in small-size catalyst pores, which is possibly a crucial factor in plasma-activated catalysis, is still not well understood. In this paper, investigations on the interactions between a helium atmospheric pressure plasma jet (APPJ) and catalysts with micrometer-sized pores of different shapes and sizes are conducted with a 2D fluid model. Simulation results show that the existence of pores makes a subtle difference to the APPJ by changing the equivalent capacitance, indicating the potential to achieve moderate and stable APPJ-catalyst interactions. Traces of air impurities in helium can promote discharges in catalyst pores, and thus allow discharges to form in smaller pores. In the case when the catalyst channel is too small for direct APPJ penetration, we propose a method by producing a prior discharge in a relatively large cavity to supply seed electrons to ignite discharges inside the channel. The effects of channel and cavity sizes are discussed from the perspectives of discharge behavior and plasma-surface interactions. This work will contribute to the preparation of structured catalysts to potentially achieve higher efficient plasma catalysis, and better understanding of the physical processes in plasma-surface interactions inside micrometer pores.