Direct-coupled plasma-assisted combustion using a microwave waveguide torch

Stephen Hammack, Xing Rao, Tonghun Lee, Campbell Carter

Research output: Contribution to journalArticlepeer-review


A tunable microwave waveguide is used to initiate and enhance combustion by coupling an atmospheric plasma discharge to a premixed methane/air flame. The absorbed microwave power ranges from 60 to 150 W, which was generated from a continuous source operating at 2.45 GHz, whereas combustion power ranges from 200 to 1000 W. OH radical number densities were measured using planar laser-induced fluorescence (PLIF), and temperatures were measured using Rayleigh scattering thermometry for various flow rates, equivalence ratios, and power levels. Increases in reaction volume, OH density, and temperature were observed as power increased. In the plasma-coupled premixed flame, OH number densities, which are quantified on the order of 10 16 cm -3, increased by up to 50%, and temperature ranging from 2000 to 3000 K increased by up to 40% as the absorbed microwave power was increased from 60 to 130 W. Air-only plasma discharges exhibited a much greater temperature increase, i.e., up to 190%. The power associated with the measured temperature increases varied greatly with flow and input power but are typically three to four times greater in the air-only plasma compared to the flame coupled plasma, demonstrating a greater degree of nonthermal mechanisms present in plasma-enhanced flame discharge.

Original languageEnglish (US)
Article number5993548
Pages (from-to)3300-3306
Number of pages7
JournalIEEE Transactions on Plasma Science
Issue number12 PART 1
StatePublished - Dec 2011
Externally publishedYes


  • Energetically enhanced combustion
  • Rayleigh scattering thermometry
  • microwave plasma
  • planar laser-induced fluorescence (PLIF)
  • plasma-assisted combustion (PAC)

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Condensed Matter Physics


Dive into the research topics of 'Direct-coupled plasma-assisted combustion using a microwave waveguide torch'. Together they form a unique fingerprint.

Cite this