The free recovery of wall-stabilised arcs with imposed laminar and turbulent flows

Abstract

Voltage probe measurements are presented for the free recovery period of wall-stabilised arcs subjected to an axial flow of nitrogen. Results are reported for 15, 25 and 45 A arcs in a 2.5 mm radius stabilising bore and for 30 and 50 A arcs in a 5 mm radius bore with mass flow rates in the range 0-0.6 g s-1. The measurements show that the conductance decay rate increases with mass flow rate and that, although this increase is most pronounced in the flow entrainment region, a significant increase is also observed in the fully developed column region. The observed experimental trends are explained in terms of a boundary layer arc model which includes turbulent diffusion effects.

Perturbed Arcs in Turbulent Axial Gas Flow IV. Thermal Reignition Experiments

“…On the other hand development research into high-voltage power circuit breaker arcs was conducted in full-scale nozzles with intensive coolant gas flow and a recovering voltage [5-6], but the stochastic properties of breaker arc interaction with turbulent gas coolant flow were accounted for only scarcely. In this paper we try to continue the work of € h~ and ,JONES [4] in constant area channels with quite stronger gas coolant flow and with regard to stochasticity. We feel encouraged to do experimental modelling at smaller lrtngt h scale and weaker current intensity by the excellent technical model research of KAGAJUTSU 171 for circuit breaker nozzle development.…”