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

Abstract

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.

References

[1] R. Soundararajan, T. Gundersen, M. Ditaranto, Oxy-combustion coal
based power plants: study of operating pressure, oxygen purity and
downstream purification parameters, Chemical Engineering Transactions
39 (2014) 229–234.
[2] S. G. Sundkvist, A. Dahlquist, J. Janczewski, M. Sjödin, M. Bysveen,
M. Ditaranto, Ø. Langørgen, M. Seljeskog, M. Siljan, Concept for a
combustion system in oxyfuel gas turbine combined cycles, Journal of
Engineering for Gas Turbines and Power 136 (10) (2014) 101513.
[3] R. Stanger, T.Wall, R. Spoerl, M. Paneru, S. Grathwohl, M.Weidmann,
G. Scheffknecht, D. McDonald, K. Myöhänen, J. Ritvanen, et al., Oxyfuel
combustion for CO2 capture in power plants, International Journal
of Greenhouse Gas Control 40 (2015) 55–125.
[4] P. Glarborg, L. L. Bentzen, Chemical effects of a high co2 concentration
in oxy-fuel combustion of methane, Energy & Fuels 22 (1) (2007)
291–296.
[5] W. Jerzak, The effect of adding co2 to the axis of natural gas combustion
flame on the variations in co and nox concentrations in the combustion
chamber, Journal of Power Technologies 94 (3) (2014) 202–
210.
[6] S. Hjartstam, F. Normann, K. Andersson, F. Johnsson, Oxy-fuel combustion
modeling: performance of global reaction mechanisms, Industrial
& Engineering Chemistry Research 51 (31) (2012) 10327–10337.
[7] P. Kutne, B. K. Kapadia, W. Meier, M. Aigner, Experimental analysis of
the combustion behaviour of oxyfuel flames in a gas turbine model
combustor, Proceedings of the Combustion Institute 33 (2) (2011)
3383–3390.
[8] M. Ditaranto, J. Hals, Combustion instabilities in sudden expansion
oxy–fuel flames, Combustion and Flame 146 (3) (2006) 493–512.
[9] B. L. Norheim, Lift-off of methane jet flames in o2/co2 atmospheres,
Master’s thesis, Norwegian University of Science and Technology
(2009).
[10] J. Sautet, L. Salentey, M. Ditaranto, J. Samaniego, Length of natural
gas-oxygen non-premixed flames, Combustion science and technology
166 (1) (2001) 131–150.
[11] M. Ditaranto, T. Oppelt, Radiative heat flux characteristics of methane
flames in oxy-fuel atmospheres, Experimental Thermal and Fluid Science
35 (7) (2011) 1343–1350.
[12] K. Bhadraiah, V. Raghavan, Numerical simulation of laminar co-flow
methane–oxygen diffusion flames: effect of chemical kinetic mechanisms,
Combustion Theory and Modelling 15 (1) (2010) 23–46.
[13] C. Galletti, G. Coraggio, L. Tognotti, Numerical investigation of oxynatural-
gas combustion in a semi-industrial furnace: validation of cfd
sub-models, Fuel 109 (2013) 445–460.
[14] Z. Mei, J. Mi, F. Wang, P. Li, J. Zhang, Chemical flame length of a
methane jet into oxidant stream, Flow, Turbulence and Combustion
4 (94) (2015) 767–794.
[15] F. Christo, B. B. Dally, Modeling turbulent reacting jets issuing into a hot
and diluted coflow, Combustion and flame 142 (1) (2005) 117–129.
[16] A. Frassoldati, P. Sharma, A. Cuoci, T. Faravelli, E. Ranzi, Kinetic
and fluid dynamics modeling of methane/hydrogen jet flames in diluted
coflow, Applied Thermal Engineering 30 (4) (2010) 376–383.
[17] Z. Mei, J. Mi, F. Wang, C. Zheng, Dimensions of ch4-jet flame in hot
o2/co2 coflow, Energy & Fuels 26 (6) (2012) 3257–3266.
[18] Y. Kang, X. Lu, Q. Wang, X. Ji, S. Miao, J. Xu, G. Luo, H. Liu, Experimental
and modeling study on the flame structure and reaction zone
size of dimethyl ether/air premixed flame in an industrial boiler furnace,
Energy & Fuels 27 (11) (2013) 7054–7066.
[19] G. Krishnamoorthy, A new weighted-sum-of-gray-gases model for
oxy-combustion scenarios, International Journal of Energy Research
37 (14) (2013) 1752–1763.
[20] R. Johansson, K. Andersson, B. Leckner, H. Thunman, Models for
gaseous radiative heat transfer applied to oxy-fuel conditions in boilers,
International Journal of Heat and Mass Transfer 53 (1) (2010) 220–
230.
[21] H. Abdul-Sater, G. Krishnamoorthy, M. Ditaranto, Predicting radiative
heat transfer in oxy-methane flame simulations: an examination of
its sensitivities to chemistry and radiative property models, Journal of
Combustion 2015.
[22] P. Nakod, G. Krishnamoorthy, M. Sami, S. Orsino, A comparative evaluation
of gray and non-gray radiation modeling strategies in oxy-coal
combustion simulations, Applied Thermal Engineering 54 (2) (2013)
422–432.
[23] Z. Wheaton, D. Stroh, G. Krishnamoorthy, M. Sami, S. Orsino,
P. Nakod, A comparative study of gray and non-gray methods of computing
gas absorption coefficients and its effect on the numerical predictions
of oxy-fuel combustion, Industrial Combustion (2013) 1–14.
[24] ANSYS Inc., Canonsburg, PA, ANSYS FLUENT User’s Guide, Version
15 (2014).
[25] M. D. Smooke (Ed.), Reduced kinetic mechanisms and asymptotic approximation
for methane-air flames: a topical volume, Vol. 384 of Lecture
Notes in Physics, Springer-Verlag, Berlin, 1991.
[26] J. Van Doormaal, G. Raithby, Enhancements of the simple method
for predicting incompressible fluid flows, Numerical heat transfer 7 (2)
(1984) 147–163.
[27] S. Patankar, Numerical heat transfer and fluid flow, CRC press, Washington,
DC, 1980.
[28] B. Leonard, S. Mokhtari, Ultra-sharp nonoscillatory convection
schemes for high-speed steady multidimensional flow, in: NASATM1-
2568 (ICOMP-90-12), NASA Lewis Research Center, 1990.
[29] H. K. Kim, Y. Kim, S. M. Lee, K. Y. Ahn, Studies on combustion characteristics
and flame length of turbulent oxy- fuel flames, Energy & fuels
21 (3) (2007) 1459–1467.
Published
2018-02-09
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: <https://papers.itc.pw.edu.pl/index.php/JPT/article/view/823>. Date accessed: 23 july 2021.
Section
Combustion and Fuel Processing

Keywords

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

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