Volumetric emission of argon plasmas in the presence of vapors of Fe,Si, and Al

The net volumetric emission was calculated for argon plasmas at atmospheric pressure in the presence of metal vapors for different elements, over the temperature range from 3000 to 30,000 K. The computations are based on the escape factor model, using a semi-empirical method for the determination of line profiles and line broadening effects. Results for iron, .silicon, and aluminum show an important influence of the presence of even the smallest concentrations of the metal vapors on the net emission coefficient of the plasma. The effect is strongest for iron, followed by aluminum and .silicon. Special attention is given to self-absorption effects which are most important in the first millimeter o% the optical path of the emitted radiation. The effect is incorporated into the calculation procedure of the net emission coefficient and can be used as a volumetric energy sink as long as the absorption length is shorter than the radius of the control volume used in the computation scheme.