130 / 2022-03-14 00:01:44

Numerical simulation of vacuum arc subject to axial magnetic field in vacuum interrupter

Vacuum arc;,magnetohydrodynamics,axial magnetic field

During the interruption process of the vacuum switch, it is unavoidable ablation will be observed on electrode surfaces, which will seriously affect the life of vacuum switch. The application of AMF could make the energy flux density(EFD) of vacuum arc(VC) injected into the electrodes relatively uniform, so as to effectively control the arc mode. However the vacuum switch is fully sealed inside, so simulation is an essential method for diagnosing VC parameters, which is of great significance for guiding the design and development of vacuum switches. The 3D magnetohydrodynamics(MHD) model of VC is established based on ANSYS FLUENT. FLUENT solver is used to solve the fluid of ions, and electron temperature equation and Maxwell equations are calculated based on user-defined modules to realize the flow-thermal-electric multi-physics program. Comparing the EFD curves of the anode surface with 5mT/kA AMF and no AMF applied at the current order of 40kA, 50kA and 60kA, it was found that the application of AMF made the EFD curve significantly uniform. Under the same current magnitude, the greater the applied AMF, the better control effect on EFD curve. It was also found that increasing electrode surface area had the similar effect with applying AMF. For controlling the VC mode, applying AMF is an effective method which has the ability to make EFD distribution uniform. However, a higher AMF means more electrode slots, and the strength requirements will also become higher under high current conditions, so it is necessary to compromise between applying AMF and electrode surface area within a reasonable range.