Temperature and Radiant Power emitted from DC Free Arc mixed with Tungsten Vapor in Air

Abstract

The radiant power emitted from a high temperature medium is useful for lighting and treatment of hazardous waste because it has a highly intense radiation. In this paper, we tried to measure the temperature and radiant power of DC free arc mixed with tungsten vapor between tungsten electrodes with a spectroscope and a power meter in air and calculate the radiant efficiency and radiant power density to know the fundamental relationship between the temperature and radiant power and to apply it to the lighting and plasma treatment. The radiant power was measured to be about 860—2, 100W at 30—70A in current, and the radiant energy was calculated to be about 27—43kJ at 35—55kJ in electrical input energy, and increases in proportion to the 1.06th power of the input energy. The temperature was measured to be about 9, 000K at 30 and 50A and to be 6, 400K at 70A. The radiant efficiency is up to 80%. The temperature was same value in different currents under 50A, even if the radius of free arc at 50A could be bigger than that at 30A. When the current is increased from 50A, the temperature is decreased. But the radiant power density is almost same value at 9, 000K(50A) and 6, 400K(70A) at mixture ratio of W: X_W = 2.5%. So, it is assumed that the radiant power depends on the radius. The logarithmic slope of the current for the radiant power was lower than that in case of the wall-stabilized model and torch plasma, because the radiant power depended on the radius and temperature of the arc.