On the gas dynamics of HVOF thermal sprays

C. M. Hackett, G. S. Settles, J. D. Miller

Research output: Contribution to journalReview article

18 Citations (Scopus)

Abstract

An experimental study of the gas-dynamic aspects of the high-velocity oxyfuel (HVOF) thermal spray process has been performed using commercially available HVOF equipment (Hobart-Tafa JP-5000, Ho-bart-Tafa Technologies, Inc., Concord, NH). Optical diagnostic techniques, including microsecond-expo-sure schlieren and shadowgraph imaging, were applied to visualize the hot supersonic jet produced by this equipment without particle injection. Rapid turbulent mixing of the jet with the surrounding atmos-phere was observed, which is an issue of concern in coating quality due to the possibility of oxidation of sprayed particles. This mixing appears to be a function of the ratio of densities of the hot jet and the cold atmosphere as well as a function of the velocity of the jet, rather than one of combustion-chamber pres-sure or barrel length. The supersonic core of the HVOF jet dissipates rapidly due to the mixing, so that the jet is no longer supersonic when it impinges on the target surface being sprayed. Secondary issues also observed in this study include strong jet-noise radiation from the HVOF plume and the entrainment and induced bulk motion of the surrounding air.

Original languageEnglish (US)
Pages (from-to)299-304
Number of pages6
JournalJournal of Thermal Spray Technology
Volume3
Issue number3
DOIs
StatePublished - Sep 1 1994

Fingerprint

Gas dynamics
gas dynamics
sprayers
jet aircraft noise
shadowgraph photography
turbulent mixing
jet flow
entrainment
combustion chambers
plumes
Air entrainment
Combustion chambers
Hot Temperature
injection
coatings
atmospheres
oxidation
air
radiation
Imaging techniques

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Materials Chemistry

Cite this

Hackett, C. M. ; Settles, G. S. ; Miller, J. D. / On the gas dynamics of HVOF thermal sprays. In: Journal of Thermal Spray Technology. 1994 ; Vol. 3, No. 3. pp. 299-304.
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On the gas dynamics of HVOF thermal sprays. / Hackett, C. M.; Settles, G. S.; Miller, J. D.

In: Journal of Thermal Spray Technology, Vol. 3, No. 3, 01.09.1994, p. 299-304.

Research output: Contribution to journalReview article

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