Abstract
An accurate determination of electron density, temperature, and velocity distributions is of primary interest for the characterization of steady-state thermal plasma spray jets. Our diagnostic capabilities based on optical emission spectroscopy include measurements of absolute emission coefficients and Stark broadening. In addition, enthalpy probe diagnostics has also been used for temperature and velocity measurements. Observation of large discrepancies between temperatures derived from absolute emission coefficients, Stark broadening, and from enthalpy probe measurements indicate that severe deviations from LTE (local thermal equilibrium) exist in various regimes of plasma spray jets. Nonequilibrum characterization of such turbulent thermal plasma jets suggests that diffusion of high-energy electrons into the fringes of plasma jets and deviations from chemical equilibrium due to high velocities in the core of plasma jets and entrainment of cold gas, are the main reasons for these discrepancies. The establishment of a reliable data base, taking these nonequilibrium effects into account, is a prerequisite for meaningful modeling of real plasma jets.
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W. L. T. Chen and E. Pfender,Proc. of 9th International Symposium on Plasma Chemistry, Pugnochiuso, Italy (1989), p. 330.
W. L. T. Chen and E. Pfender, Enthalpy probe and spectroscopic measurements in thermal plasma jets,Report, ERC for Plasma-Aided Manufacturing, Department of Mechanical Engineering, University of Minnesota (1990).
E. Pfender, W. L. T. Chen, and R. Spores,Proc. of 1990 National Thermal Spray Conference, Long Beach, California (1990), p. l.
E. Pfender, W. L. T. Chen, C.-P. Chiu, and J. Heberlein,Studies of a Turbulent Argon Helium Plasma Jet, 1991 National Thermal Spray Conference, Pittsburgh, Pennsylvania (1991).
W. L. T. Chen, J. Heberlein, and E. Pfender,Proc. of 10th International Symposium on Plasma Chemistry, Bochum, Germany, 1.2 12 (1991).
W. L. T. Chen, J. Heberlein, and E. Pfender,Experimental Measurements of Plasma Properties for Miller SG-100 Torch with Mach I Setting, Idaho National Engineering Laboratory Report, EGG-SCM-9576, EG&G Idaho, Inc., Idaho Falls, Idaho (1991).
E. Pfender, W. L. T. Chen, C.-P. Chiu, and J. Heberlein,Properties of a Turbulent ArgonHelium Plasma Jet, Werkstofftechnologie in Wandel, H. Kern, ed., Deutscher Verlag für Schweisstechnik, Düsseldorf, Germany (1991), p. 71.
W. L. T. Chen, J. Heberlein, and E. Pfender,Proc. of Symposium on Thermal Plasma Applications in Materials and Metallurgical Processing, TMS Annual Meeting, San Diego, California (1992), p. 107.
W. L. T. Chen, J. Heberlein, and E. Pfender,Proc. of 1992 International Thermal Spray Conference, Orlando, Florida (1992), p. 327.
E. Pfender, J. Fincke, and R. Spores,Plasma Chem. Plasma Process. 11, 529 (1991).
P. Kepple and H. R. Griem,Phys. Rev. 173, 317 (1968).
C. R. Vital, J. Cooper, and E. W. Smith,J. Quant. Spectrosc. Radiat. Transfer 11, 263 (1970).
W. L. Wiese, D. E. Kelleher, and D. R. Paquette,Phys. Rev. A 6, 1132 (1972).
R. C. Preston,J. Quant. Spectrosc. Radiat. Transfer 18, 337 (1977).
P. Baessler and M. Kock,J. Phys. B 13, 1351 (1980).
A. Scheeling, J. P. Kamla, and M. J. Zoellner,Spectrochim. Acta 39B, 677 (1984).
E. H. Choot and G. Horlick,Spectrochim. Acta 41B, 935 (1986).
C. Thomson and U. Helbig,Spectrochim. Acta 4613, 1215 (1991).
J. R. Fincke, T. J. Repetti, S. C. Snyder, G. D. Lassahn, and B. A. Detering,Proc. of Symposium on Thermal Plasma Applications in Materials and Metallurgical Processing, TMS Annual Meeting, San Diego, California (1992), p. 85.
A. J. D. Farmer and G. N. Haddad,J. Phys. D: Appl. Phys. 21, 426 (1988).
L. E. Cram, L. Poladian, and G. Roumeliotis,J. Phys. D: Appl. Phys. 21, 418 (1988).
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Chen, W.L.T., Heberlein, J. & Pfender, E. Diagnostics of a thermal plasma jet by optical emission spectroscopy and enthalpy probe measurements. Plasma Chem Plasma Process 14, 317–332 (1994). https://doi.org/10.1007/BF01447084
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DOI: https://doi.org/10.1007/BF01447084