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Recently, C/H/Ar plasma discharges found enormous potential and possibility in carbonaceous compounds conversion and production. In this work, a pulsed-dc CH3OH/Ar plasma jet generated at atmospheric pressure is investigated by means of optical and electrical diagnosis concerning the variation of its basic parameters, absolute concentration of OH radicals, and plasma temperature with different CH3OH/Ar volume ratios, in the core region of discharge with needle-to-ring electrode configuration. The voltage–current characteristics are also measured at different CH3OH/Ar ratios. Laser-induced fluorescence (LIF) results here show that only small amounts of added methanol vapor to argon plasma (about 0.05% CH3OH/Ar volume ratio) is favorable for the production of OH radicals. The optical emission lines of CH, CN, and C2 radicals have been detected in the CH3OH/Ar plasma. And, the plasma temperatures increase with successive amount of added methanol vapor to the growth plasma. Moreover, qualitative discussions are presented regarding the mechanisms for methanol dissociation and effect of the CH3OH component on the Ar plasma discharge at atmospheric pressure. [ABSTRACT FROM AUTHOR]

Two Stark broadening parameters including FWHM (full width at half maximum) and FWHA (full width at half area) of isotope hydrogen alpha lines are simultaneously introduced to determine the electron density of a pulsed vacuum arc jet. To estimate the gas temperature, the rotational temperature of the C2 Swan system is fit to 2500±100 K. A modified Boltzmann-plot method with bi-factor is introduced to determine the modified electron temperature. The comparison between results of atomic and ionic lines indicates the jet is in partial local thermodynamic equilibrium and the electron temperature is close to 13 000±400 K. Based on the computational results of Gig-Card calculation, a simple and precise interpolation algorithm for the discrete-points tables can be constructed to obtain the traditional ne-Te diagnostic maps of two Stark broadening parameters. The results from FWHA formula by the direct use of FWHM=FWHA and these from the diagnostic map are different. It can be attributed to the imprecise FWHA formula form and the deviation between FWHM and FWHA. The variation of the reduced mass pair due to the non-equilibrium effect contributes to the difference of the results derived from two hydrogen isotope alpha lines. Based on the Stark broadening analysis in this work, a corrected method is set up to determine ne of (1.10±0.08)×1021m-3, the reference reduced mass 10 pair of (3.30±0.82 and 1.65±0.41), and the ion kinetic temperature of 7900±1800 K. [ABSTRACT FROM AUTHOR]