Plasma thermal-chemical instability of low-temperature dimethyl ether oxidation in a nanosecond-pulsed dielectric barrier discharge

Hongtao Zhong, Xin Yang, Xingqian Mao, Mikhail N. Shneider, Igor V. Adamovich, Yiguang Ju

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Plasma stability in reactive mixtures is critical for various applications from plasma-assisted combustion to gas conversion. To generate stable and uniform plasmas and control the transition towards filamentation, the underlying physics and chemistry need a further look. This work investigates the plasma thermal-chemical instability triggered by dimethyl-ether (DME) low-temperature oxidation in a repetitive nanosecond pulsed dielectric barrier discharge. First, a plasma-combustion kinetic mechanism of DME/air is developed and validated using temperature and ignition delay time measurements in quasi-uniform plasmas. Then the multi-stage dynamics of thermal-chemical instability is experimentally explored: the DME/air discharge was initially uniform, then contracted to filaments, and finally became uniform again before ignition. By performing chemistry modeling and analyzing the local thermal balance, it is found that such nonlinear development of the thermal-chemical instability is controlled by the competition between plasma-enhanced low-temperature heat release and the increasing thermal diffusion at higher temperature. Further thermal-chemical mode analysis identifies the chemical origin of this instability as DME low-temperature chemistry. This work connects experiment measurements with theoretical analysis of plasma thermal-chemical instability and sheds light on future chemical control of the plasma uniformity.

Original languageEnglish (US)
Article number114003
JournalPlasma Sources Science and Technology
Volume31
Issue number11
DOIs
StatePublished - Dec 2022

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

Keywords

  • dielectric barrier discharges
  • dimethyl ether
  • low-temperature chemistry
  • plasma thermal-chemical instability
  • repetitive nanosecond pulses

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