Plasma arc simulation of high voltage circuit breaker with a hybrid 2D/3D model

A hybrid 2D-3D CFD (Computational Fluid Dynamics) model is developed for studying plasma arc behavior in high voltage circuit breaker. Usually the shape of HVCB is simplified to axisymmetric in CFD analysis. And the plasma arc also maintains axisymmetric characteristics during high current situation, so axisymmetric analysis is valid when the current is sufficiently high. But near the current zero point where of accuracy is crucial, the shape of the arc changes into a filament-like shape and axisymmetric analysis is no longer valid. In this study the arc core region is modeled as 3D and outer region is modeled as 2D axisymmetric in order to save calculation cost. Electrodynamic potential solver directly calculates electric current and ohmic heating with the electrical conductivity table according to the local equilibrium gas pressure and temperature. Metal vapor and PTFE vapor due to the ablation are considered and the discrete ordinate method (DOM) is used to solve the radiation heat transfer with 10 spectral bands of absorption coefficient. Circumferentially averaged pressure, temperature and species fraction are transferred from 3D to 2D domain. And the same variables are transferred from 2D to 3D as functions of radius. Simulation results are compared with the measured pressure and arc voltage, and the results successfully capture the current zero characteristics as well as interruption performance.