M. Claessens et al., SIMULATION OF GAS-FLOW PHENOMENA IN HIGH-VOLTAGE SELF-BLAST CIRCUIT-BREAKERS AT HEAVY FAULT CURRENT INTERRUPTION, IEEE transactions on plasma science, 25(5), 1997, pp. 1001-1007
CFD (computational fluid dynamics) calculations for high-and low-curre
nt arcs in an interrupter of the self-blast type have been performed.
The high-current simulation provides information about the mixing proc
ess of the hot PTFE cloud with the cold SF6 which is difficult to acce
ss for measurement. In addition, it yields the gas state inside the pr
essure chamber when the fault current approaches its current zero, Dep
ending on the arcing time, fault current and interrupter geometry blow
temperatures of up to 2000 K with a PTFE mass fraction of up to 10% h
ave been found, The low-current simulation performed for this blow tem
perature gives detailed information about the are behavior in the time
immediately before current zero. Special attention has been paid to t
he how phenomena in the expanding nozzle region, Due to the interactio
n of the supersonic flow with the obtuse arcing contact and the nozzle
geometry, a complex flow structure with a shock is established. This
has been simulated for low-current arcs in an extinguishing flow with
boundary conditions as obtained from the high-current simulation.