Predicting Chemical Flame Lengths and Lift-off Heights in Enclosed, Oxy-Methane Diffusion Flames at Varying O2/CO2 Oxidizer Dilution Ratios

  • Gautham Krishnamoorthy
  • Mario Ditaranto


Experiments have shown reactor confinement, wall temperatures and radiative transfer to influence the flame length and lift-offcharacteristics of oxy-methane flames. In this study, the performances of the Shear Stress Transport (SST) k-! turbulencemodel, a skeletal methane combustion mechanism (16 species and 41 reactions) and two weighted sum of gray gas models(WSGGM) towards capturing these flame characteristics are evaluated against measurements obtained from oxy-methaneflames across a wide range of oxidizer O2/CO2 ratios and fuel Reynolds numbers. Gas composition, gas and wall temperatures,flame length measurements and inferences of lift-off heights from OH* chemiluminescence imaging are employed inthe assessment. The corresponding numerical estimate of flame length and lift-off heights were made by determining theflame shape by the locus of points at which the CO concentrations reduce to 1% of their peak values within the flame.The predicted gas temperatures and compositions compared reasonably well against measurements. The criterion fordefining the flame shape based on CO concentrations appears promising since the trends in chemical flame length andlift-off height predictions agreed reasonably well with the measurements across the range of oxidizer concentrations andfuel Reynolds numbers. Flame length prediction sensitivities to the wall temperatures and the WSGGM model were alsoassessed.


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How to Cite
KRISHNAMOORTHY, Gautham; DITARANTO, Mario. Predicting Chemical Flame Lengths and Lift-off Heights in Enclosed, Oxy-Methane Diffusion Flames at Varying O2/CO2 Oxidizer Dilution Ratios. Journal of Power Technologies, [S.l.], v. 97, n. 4, p. 370–377, feb. 2018. ISSN 2083-4195. Available at: <>. Date accessed: 23 july 2024.
Combustion and Fuel Processing


Oxy-methane; combustion model; flame length; lift-off height; WSGGM.

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