Estimation of electron density and temperature in an argon rotating gliding arc using optical and electrical measurements

This work reports average electron temperature (⁠$Te$⁠) and electron density (⁠$ne$⁠) of an atmospheric argon rotating gliding arc (⁠$RGA$⁠), operated in glow-type mode, under transitional and turbulent flows. Both $Te$ and $ne$ were calculated near the shortest (⁠$δ$⁠) and longest (⁠$Δ$⁠) gap between the electrodes, by two different methods using two separate measurements: (1) optical emission spectroscopy (⁠$OES$⁠) and (2) physical–electrical. $Te$ calculated from (a) collisional radiative model (⁠$CRM$⁠) (⁠$OES$⁠) and (b) BOLSIG+ [physical–electrical, reduced electric field $(ENo)$ as input], differed each other by 16%–26% at $δ$ and 6% at $Δ$⁠. $Te$ was maximum at $δ$ (⁠$>2$ eV) and minimum near $Δ$ (1.6–1.7 eV). Similarly, the $ENo$ was maximum near the $δ$ (5–8 Td) and minimum near $Δ$⁠, reaching an asymptotic value (1 Td). By benchmarking $Te$ from $CRM$⁠, the expected $ENo$ near $δ$ was corrected to 3 Td. The calculated $CRM$ intensity agreed well with that of the measured for most of the emission lines indicating a well optimized model. The average $ne$ near $δ$ and $Δ$ from Stark broadening (⁠$OES$⁠) was 4.8–$8.0×1021$ $m−3$⁠, which is an order higher than the $ne$ calculated through current density (physical–electrical). $Te$ and $ne$ were not affected by gas flow, attributed to the glow-type mode operation. To the best of authors’ knowledge, this work reports for the first time (a) an optimized $CRM$ for $RGA$s (fine-structure resolved), (b) the poly-diagnostic approach to estimate plasma parameters, and (c) the validation of $ENo$ calculated using physical–electrical measurements.