Radiation Transfer Modeling in Thermal Plasma: NEC Calculation and Integration into an Arc Discharge Model

Accurate modeling of radiative heat transfer is essential for predicting the thermal and electromagnetic behavior of arc discharges and for designing high-performance plasma technologies. This study presents a refined approach to evaluating radiation losses in thermal plasma based on high-resolution Net Emission Coefficients (NECs) obtained with a spectral discretization of 0.1 nm over the range of 50–800 nm. Radiation losses are analyzed as a function of the plasma column radius using several specification schemes, including a component-wise cylindrical model, fixed-radius approximations, and interpolation via the modified Akima method. The calculated NECs are integrated directly into a multiphysics digital model of a free-burning arc, enabling a detailed assessment of how different radiation loss models influence the resulting temperature fields, energy transport, and current density distributions. Sensitivity analysis reveals that gas composition, plasma radius specification, and optical property variations exert the strongest impact on simulation outcomes, highlighting the dominant role of radiation in the high-temperature region of the arc. The developed methodology offers a foundation for extending radiation models to additional gas mixtures, operating pressures, and partially nonequilibrium conditions, supporting the advancement of digital twins and next-generation plasma processing technologies.