Lift-off of non-premixed turbulent CH4 jet flames at elevated pressures

T. F. Guiberti*, W. R. Boyette, A. M. Elbaz, A. R. Masri, W. L. Roberts

*Corresponding author for this work

Research output: Contribution to conferencePaperpeer-review

Abstract

In this study, the lift-off behavior of non-premixed turbulent jet flames (120 kPa to 500 kPa) is explored at elevated pressures, extending the current knowledge limited to sub-atmospheric and atmospheric pressure conditions. Experiments are conducted in the high-pressure combustion duct (HPCD) available at CCRC-KAUST. Flames are issued from a 4.58 mm inner diameter nozzle using methane as fuel and are maintained within an air coflow featuring a 0.6 m.s-1 velocity. Results show that, regardless of pressure, if the fuel jet velocity U exceeds a critical value, detachment occurs and flames are lifted and stabilized at a height h above the nozzle. The velocity leading to detachment decreases with pressure. Regardless of pressure, if the fuel jet velocity U is further increased after detachment the lift-off height h increases linearly. However, it is observed that the slope of the h(U) curve is insensitive to pressure if p ≤ 300 kPa but decreases rapidly with pressure if p > 300 kPa. One-dimensional laminar flames calculations are conducted to understand the influence of pressure on important properties of methane/air flames such as their laminar flame speed and extinction strain rate. These results are used to explain the experimental observations.

Original languageEnglish (US)
StatePublished - Jan 1 2017
Event10th U.S. National Combustion Meeting - College Park, United States
Duration: Apr 23 2017Apr 26 2017

Conference

Conference10th U.S. National Combustion Meeting
CountryUnited States
CityCollege Park
Period04/23/1704/26/17

Keywords

  • Elevated pressure
  • Lift-off
  • Non-premixed
  • Turbulent flame

ASJC Scopus subject areas

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

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