Dilution effects of superheated water vapor on turbulent premixed flames at high pressure and high temperature

Hideaki Kobayashi, Soichiro Yata, Yasuhisa Ichikawa, Yasuhiro Ogami

Research output: Contribution to journalConference articlepeer-review

40 Citations (Scopus)

Abstract

Methane/air turbulent premixed flames diluted with superheated water vapor at high-pressure and hightemperature were experimentally investigated to explore the effects of recycled water vapor on turbulent flame characteristics from the viewpoint of applying high-temperature air combustion (HiTAC) to highload combustors as well as elucidating those effects of exhaust gas recirculation (EGR) in IC engine. A newly devised water evaporator was installed in a high-pressure chamber and superheated water vapor was successfully supplied to air up to 1.0 MPa and 573 K. The maximum dilution ratio defined as the ratio of the molar fraction of H2O to those of air and H2O was 0.1. Turbulent burning velocity, mean volume and the structure of the turbulent flame region were compared with those of flames diluted with CO2, reported previously, which is another major species in recycled burnt gas. Results showed that the effects of superheated water vapor dilution on turbulent burning velocity, SV, normalized by laminar burning velocity, SL, was much weaker than that of CO2 dilution. The mean volume of the turbulent flame region defined as the region between (c) = 0.1 and (c) = 0.9, was scarcely changed either. This means that the effects of recycled burnt gas on the structure of turbulent premixed flames at high pressure and high-temperature is predominated by CO2 but not by superheated water vapor, indicating that suppression of combustion oscillation in premixed-type gas-turbine combustors by extension of the volume of heat release region is due to recycled CO2. The emission indices of CO and NOx were also measured at high pressure, and it was proved that water vapor dilution is effective to restrain CO emission, which is a possible defect of HiTAC when it is applied to gas-turbine combustors.

Original languageEnglish
Pages (from-to)2607-2614
Number of pages8
JournalProceedings of the Combustion Institute
Volume32 II
DOIs
Publication statusPublished - 2009
Event32nd International Symposium on Combustion - Montreal, QC, Canada
Duration: 2008 Aug 32008 Aug 8

Keywords

  • CO emission
  • EGR
  • HiTAC
  • Turbulent combustion
  • Water vapor

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Mechanical Engineering
  • Physical and Theoretical Chemistry

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