A computational fluid dynamics simulation of high- and low-current arcs in self-blast circuit breakers

Abstract

Computational fluid dynamics calculations for high- and low-current arcs in an interrupter of the self-blast type have been performed. The mixing process of the hot PTFE cloud with the cold in the pressure chamber is strongly inhomogeneous. The existence of two different species has been taken into account by interpolation of the material functions according to their mass fraction in each grid cell. Depending on the arcing time, fault current and interrupter geometry, blow temperatures of up to 2000 K have been found. The simulation results for a decaying arc immediately before current zero yield a significantly reduced arc cooling at the stagnation point for high blow temperatures.