Gas flow characteristics of a time modulated APPJ: The effect of gas heating on flow dynamics

S. Zhang, A. Sobota, E. M. Van Veldhuizen, P. J. Bruggeman

Research output: Contribution to journalArticlepeer-review

46 Scopus citations

Abstract

This work investigates the flow dynamics of a radio-frequency (RF) non-equilibrium argon atmospheric pressure plasma jet. The RF power is at a frequency of 50Hz or 20kHz. Combined flow pattern visualizations (obtained by shadowgraphy) and gas temperature distributions (obtained by Rayleigh scattering) are used to study the formation of transient vortex structures in initial flow field shortly after the plasma is switched on and off in the case of 50Hz modulation. The transient vortex structures correlate well with observed temperature differences. Experimental results of the fast modulated (20kHz) plasma jet that does not induce changes of the gas temperature are also presented. The latter result suggests that momentum transfer by ions does not have dominant effect on the flow pattern close to the tube. It is argued that the increased gas temperature and corresponding gas velocity increase at the tube exit due to the plasma heating increases the admixing of surrounding air and reduces the effective potential core length. With increasing plasma power a reduction of the effective potential core length is observed with a minimum length for 5.6W after which the length extends again. Possible mechanisms related to viscosity effects and ionic momentum transfer are discussed.

Original languageEnglish (US)
Article number015203
JournalJournal of Physics D: Applied Physics
Volume48
Issue number1
DOIs
StatePublished - Jan 14 2015

Keywords

  • Kelvin Helmholtz instability
  • effective potential core flow
  • flow pattern
  • gas temperature
  • shadowgraphy
  • vortex structures

Fingerprint Dive into the research topics of 'Gas flow characteristics of a time modulated APPJ: The effect of gas heating on flow dynamics'. Together they form a unique fingerprint.

Cite this