Current density and temperature distribution along a horizontal electrode in an all-electric glass melting furnace

Abstract

Temperature in the immediate vicinity of the heating electrode has been measured in a real all-electric glass furnace, equipped with horizontal electrodes and melting lead crystal glass, as well as in its low-temperature physical model. It has been found by direct measurement in the real furnace that the maximum temperature difference between the electrode body and the molten glass in horizontal distance of 20 cm away from the electrode was only 9 K. In contrast to the actual current density, which reaches the highest values at the very tip and then decreases rapidly, the temperature maximum was not found at the tip of the electrode, but occurred approximately at two thirds of its length. The increase in the temperature of the melt in the vicinity of the electrode compared with the temperature at the electrode surface has been tried to measure in the low-temperature physical model. This temperature increase has been found immeasurably low and within a very small distance from the electrode, but its existence has clearly been demonstrated in a model experiment at about 4.5 times higher current loading of the electrode than in the basic adjustment of the model parameters. The actual current density at the electrode tip was about twice higher than the mean current density at the electrode both in the real furnace and in the model.