Journal of Thermal Spray Technology

, Volume 2, Issue 4, pp 345–350 | Cite as

Entrainaient and demixing in subsonic argon/helium thermal plasma jets

  • J. R. Fincke
  • W. D. Swank
  • D. C. Haggard
Reviewed Paper


The velocity, temperature, entrained air fraction, and Ar/He concentration profiles were measured in a subsonic thermal plasma jet using an enthalpy probe and mass spectrometer. Through interaction with the surrounding atmosphere, air is quickly entrained into the jet, resulting in rapidly decreasing velocities and temperatures. Due to the difference in ionization potential, a significant diffusive separation or demixing of Ar and He is also observed in the large temperature gradients present. Near the exit of the torch, in the jet center, the relative He concentration is enhanced by approximately 50% over that of the premixed feed gases. Demixing occurs primarily in the discharge region and torch nozzle. As jet mixing progresses in the downstream direction, the Ar to He ratio approaches the initial input ratio.

Key words

argon/helium plasmas diagnostics enthalpy probe entrainment control mass spectrometer plasma jet 


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  1. 1.
    E. Pfender, J.R. Fincke, and R. Spores, Entrainment of Cold Gas into Thermal Plasma Jets,Plasma Chem. Plasma Proc, Vol 11, 1991, p 529–542CrossRefGoogle Scholar
  2. 2.
    J.R. Fincke, R. Rodriguez, and CG. Pentecost, Coherent Anti-Stokes Raman Spectroscopic Measurement of Air Entrainment in Argon Plasma Jets,Plasma Processing and Synthesis of Materials III, Materials Research Society Symposia Proc, Vol 190, D. Apelian and J. Szekely.Ed., 1991, p 184–189Google Scholar
  3. 3.
    J.R. Fincke, R. Rodriguez, and CG. Pentecost, Measurement of Air En- trainment in Plasma Jets,Thermal Spray Research and Applications, T.F. Bernecki, Ed., ASM International, 1991, p 45–48Google Scholar
  4. 4.
    R. Spores and E. Pfender, Flow Structure of a Turbulent Plasma Jet,Thermal Spray: Advances in Coatings Technology, D.L. Houck, Ed., ASM International, 1988, p 85–92Google Scholar
  5. 5.
    M. Vardelle, A. Vardelle, Ph. Roumilhac, and P. Fauchais, Influence of the Surrounding atmosphere Under Plasma Spraying Conditions,Thermal Spray: Advances in Coatings Technology, D.L. Houck, Ed., ASM International, 1988, p 117–121Google Scholar
  6. 6.
    W. Frie and H. Maecker, Massentrennung durch Diffusion Reagieren- der Gase,Z. Physik Bd., Vol 162,1961, p 69–83 (in German)CrossRefGoogle Scholar
  7. 7.
    H. Maecker, Fortschritte in der Bogenphysik,Proc. 5th Int. Conf. Ioni- zation Phenomena in Gases, North-Holland, p 1793–1811Google Scholar
  8. 8.
    J. Richter, Uber Difftisionsvorgange in Lichtbogen,Z. Astrophysik, Vol 53, 1961, p 262–272 (in German)Google Scholar
  9. 9.
    W. Frie, Berechnung der Gasusammensetzung und der Materialfunk- tionen von SF6,Z. Physik, Bd., Vol 201, 1967, p 269–294, in GermanCrossRefGoogle Scholar
  10. 10.
    D. Vukanovic and V. Vukanovic, On the Behavior of Hydrogen Isotopes in a DC Arc Plasma,Spectrochimica Acta, Vol 24B, 1969, p 579–583Google Scholar
  11. 11.
    G. Baruschka and E. Schulz-Gulde, Transition Probabilities for F I Lines from Wall Stabilized Arc Measurements,Astronotics Astrophys- ics, Vol 44, 1975, p 335–342Google Scholar
  12. 12.
    E. Fisher, Axial Segregation of Additives in Mercury-Metal-Halide Arcs,J. Appl. Phys.,Vol 47, 1976, p 2954–2960CrossRefGoogle Scholar
  13. 13.
    H.-P. Stormberg, Axial and Radial Segregation in Metal Halide Arcs,J. Appl. Phys.,Vol52, 1981, p 3233–3237CrossRefGoogle Scholar
  14. 14.
    J. Grey, Thermodynamic Methods of High-Temperature Measurement,ISA Trans., Vol 4, 1965, p 102–115Google Scholar
  15. 15.
    S. Katta, J.A. Lewis, and W.H. Galvin, A Plasma Calorimetric Probe,Rev. Sci. Instr, Vol 44, 1975, p 1519–1523CrossRefGoogle Scholar
  16. 16.
    J. Grey, P.F. Jacobs, and M.P. Sherman, Calorimetric Probe for the Measurement of Extremely High Temperatures,Rev. Sci. Instr., Vo133, 1962, p 738–741CrossRefGoogle Scholar
  17. 17.
    J. Grey, Sensitivity Analysis for The Calorimetric Probe,Rev. Sci. Instr., Vol 34, 1963, p 857–859CrossRefGoogle Scholar
  18. 18.
    T.J. O’Connor, E.H. Comfort, and L.A. Cass, Turbulent Mixing of an Axisymmetric Jet of Partially Dissociated Nitrogen with Ambient Air,AIAA J., Vol 4,1966, p 2026–2032CrossRefGoogle Scholar
  19. 19.
    L.A. Anderson and R.E. Sheldahl, Experiments With Two Flow-Swal- lowing Enthalpy Probes in High-Energy Supersonic Streams,AIAA J., Vol 9,1971, p 1804–1810Google Scholar
  20. 20.
    W.L.T. Chen, J. Heberlein, and E. Pfender, “Experimental Measurements of Plasma Properties for Miller SG-100 Torch with Mach I Settings. Part 1 : Enthalpy Probe Measurements,≓ Report, Engineering Research Center for Plasma-Aided Manufacturing, Dept. of Mech. Engr., Univ. of Minn., Aug 1990Google Scholar
  21. 21.
    M. Brossa and E. Pfender, Probe Measurements in Thermal Plasma Jets,Plasma Chem. Plasma Proc.,Vol 8,1988, p75–90CrossRefGoogle Scholar
  22. 22.
    A. Capetti and E. Pfender, Probe Measurements in Argon Plasma Jets Operated in Ambient Argon,Plasma Chem. Plasma Proc, Vol 9, 1989, p 329–339CrossRefGoogle Scholar
  23. 23.
    P. Stefanovic, P. Pavlovic, and M. Jankovic, High Sensitive Calorimet- ric Probe for Diagnostics Thermal Plasma at the Exit of Electric Arc Heater,Proc. 9th Int. Symp. Plasma Chemistry, IUPAC, Vol 1,1989, p314–319Google Scholar
  24. 24.
    W.D. Swank, J.R. Fincke, and D.C. Haggard, Modular Enthalpy Probe and Gas Analyzer for Thermal Plasma Measurements,Rev.Sci. Instr., Vol 64,1993, p 56–62CrossRefGoogle Scholar
  25. 25.
    J.R. Fincke, S.C. Snyder, and W.D. Swank, Comparison of Enthalpy Probe and Laser Light Scattering Measurement of Thermal Plasma Temperatures and Velocities,Rev.Sci. Instr, Vol 64, 1993, p 711–724CrossRefGoogle Scholar
  26. 26.
    J.R. Fincke, W.D. Swank, S.C. Snyder, and D.C. Haggard, Detached Shock Enthalpy Probe Performance,Proc. Int. Symp. Plasma Chem- istry, ISPC-11, IUPAC, Leicestershire, UK, Aug 1993, p 475–480Google Scholar
  27. 27.
    I.M. Hall, The Displacement Effect of a Sphere in a Two-Dimensional Shear Flow,J. Fluid Mechan., Vol 1, 1956, p 142–162CrossRefGoogle Scholar
  28. 28.
    M.J. Lighthill, Contributions to the Theory of the Pitot-Tube Displace- ment Effect,J. Fluid Mechan., Vol2,1957,p493–512CrossRefGoogle Scholar
  29. 29.
    P.O.A.L. Davies, The Behavior of a Pitot Tube in Transverse Shear,J. Fluid Mechan., Vol 3, 1957, p 441–456CrossRefGoogle Scholar
  30. 30.
    G.L. Brown and A. Roshko, On Density Effects and Large Structure in Turbulent Mixing Layers,J. Fluid Mechan., Vol 64,1974, p 775–816CrossRefGoogle Scholar
  31. 31.
    P.O. Witze, Centerline Decay of Compressible Free Jets,AIAA J., Vol 12, 1974, p417–418Google Scholar
  32. 32.
    H. Schlichting,Boundary Layer Theory, McGraw Hill, 1968, p 17Google Scholar
  33. 33.
    W.E. Ranz and W.R. Marshall, Jr.,Chem. Eng. Prog., Vol 48, 1952, p 141 and Vol 48, 1952, p 173Google Scholar

Copyright information

© ASM International 1993

Authors and Affiliations

  • J. R. Fincke
    • 1
  • W. D. Swank
    • 1
  • D. C. Haggard
    • 1
  1. 1.Idaho National Engineering LaboratoryE G & G Idaho, Inc.Idaho Falls

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