Modeling of gas temperature decay after arc discharge in small air gaps

A gas temperature decay model in small air gaps after arc discharge has been developed, assuming that the recovering hot gas is a spherical lump. The calculation of the temperature decay by this model consists of the calculation of the time constants of the decay process. Time constants were determined as a function of the diameter of the spherical gas lump and the gas temperature, and were arranged to suit the actual geometrical shape of the arc channel which was measured by framing photographs. Temperature decay was calculated for different gap lengths between 1 and 7 mm and they showed a good agreement with those obtained from the experimental voltage recovery combined with the Paschen curve