Plasma Chemistry and Plasma Processing

, Volume 11, Issue 4, pp 529–543 | Cite as

Entrainment of cold gas into thermal plasma jets

  • E. Pfender
  • J. Fincke
  • R. Spores


There is increasing evidence that the entrainment of cold gas surrounding a turbulent plasma jet is more of an engulfment type process rather than simple diffusion. A variety of diagnostic techniques have been employed to determine the development of turbulence in a plasma jet and to measure concentration and temperatures of the cold gas entrained into atmospheric-pressure argon plasma jets in ambient argon or air. The results indicate that the transition to turbulence causes a rapid drop of the axial jet velocity due to entrainment of the cold gas surrounding the plasma jet. Dissipation of the cold engulfed gas bubbles by molecular diffusion is relatively slow if molecular gases (for example air) are entrained, as indicated by conditional sampling and CARS measurements. Temperature measurements using emission spectroscopy and enthalpy probes show strong discrepancies in the jet fringes.

Key words

Thermal plasma jets cold gas entrainment diagnostics 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    R. Spores and E. Pfender,Surf. Coating Technol. 37, 251 (1989).Google Scholar
  2. 2.
    M. Vardelle, A. Vardelle, Ph. Roumilhac, and P. Fauchais, Proceedings of the National Thermal Spray Conference, Cincinnati, Ohio, October 1988, p. 177.Google Scholar
  3. 3.
    M. E. Vinayo, F. Kassabji, J. Guyonnet, and P. Fauchais,J. Vac. Sci. Technol. 6, 2483 (1985).Google Scholar
  4. 4.
    D. Varacalleet al., Symposium Volume of the 1989 TMS/ASM Northeast Regional Meeting, May 1989.Google Scholar
  5. 5.
    R. Spores, “Analysis of the Flow Structure of a Turbulent Thermal Plasma Jet,” Ph.D. Thesis, Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota, December 1989.Google Scholar
  6. 6.
    R. W. Schefer, V. Hartmann, and R. W. Dibble,AIAA J. 25, 1318 (1986).Google Scholar
  7. 7.
    R. W. Dibble, V. Hartmann, and R. W. Schefer,Exp. Fluids 5, 103 (1987).Google Scholar
  8. 8.
    M. D. Levenson,Introduction to Nonlinear Laser Spectroscopy Academic Press, New York (1982).Google Scholar
  9. 9.
    R. R. Antcliff and O. Jarrett,Rev. Sci. Instrum. 58, 2075 (1987).Google Scholar
  10. 10.
    A. C. Eckbreth and T. J. Anderson,Appl. Opt. 24, 2731 (1985).Google Scholar
  11. 11.
    J. R. Fincke, R. Rodriguez, and C. G. Pentecost, “Coherent Anti-Stokes Raman Spectroscopic Measurement of Air Entrainment in Argon Plasma Jets,” Paper M 4.3, 1990 MRS Spring Meeting, San Francisco, California, April 16–21. 1990.Google Scholar
  12. 12.
    M. Brossa and E. Pfender,Plasma Chem. Plasma Process.,8, 75 (1988).Google Scholar
  13. 13.
    J. Grey, P. F. Jacobs, and M. P. Sherman,Rev. Sci. Instrum. 33, 738 (1962).Google Scholar
  14. 14.
    A. J. Yule,J. Fluid Mech. 89, 413 (1978).Google Scholar
  15. 15.
    E. J. List,Annu. Rev. Fluid Mech. 14, 189 (1982).Google Scholar
  16. 16.
    A. A. Townsend,J. Fluid Mech. 26, 689 (1966).Google Scholar

Copyright information

© Plenum Publishing Corporation 1991

Authors and Affiliations

  • E. Pfender
    • 1
  • J. Fincke
    • 1
    • 2
  • R. Spores
    • 1
    • 3
  1. 1.Department of Mechanical Engineering and ERC for Plasma-Aided ManufacturingUniversity of MinnesotaMinneapolis
  2. 2.INEL, EG&G Idaho, Inc., Idaho Falls
  3. 3.Department of the Air Force, Air Force Phillips LaboratoryEdwards Air Force BaseCalifornia

Personalised recommendations