Net emission of H2O-air-MgCl2/CaCl2/NaCl thermal plasmas

This paper is devoted to the calculation of the net radiation emitted by water-air-MgCl2/CaCl2/NaCl mixtures. Assuming a spherical, homogeneous and isothermal plasma, the net emission coefficient (NEC) is calculated for several pressures between 1 and 10 bar in the temperature range 300-30 000K under the assumption of local thermodynamic equilibrium. The various contributions to the NEC (atomic continuum, molecular continuum, molecular band and spectral lines) are presented and described. The influence of the pressure and of the proportion of air, MgCl2, CaCl2 or NaCl is analysed. It is also demonstrated that the alkaline salt resonance lines (Ca+, Ca2+, Na+, Mg+, Mg2+, Cl+ and Cl2+) have a significant effect on the NEC value in spite of their strong self-absorption.