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http://dx.doi.org/10.7842/kigas.2014.18.2.21

Characteristics of Entrainment Flow Rate in a Coanda Nozzle with or without Coaxial Contractor  

Ha, Ji Soo (Environmental Science, Keimyung University)
Shim, Sung Hoon (Korea Institute of Machinery & Materials)
Publication Information
Journal of the Korean Institute of Gas / v.18, no.2, 2014 , pp. 21-27 More about this Journal
Abstract
A MILD(Moderate and Intense Low oxygen Dilution) combustion, which is effective in the reduction of NOx, is considerably affected by the recirculation flow rate of hot exhaust gas to the combustion furnace. The present study used a coanda nozzle for the exhaust gas recirculation in a MILD combustor. A numerical analysis was accomplished to elucidate the effect of exhaust gas entrainment toward the furnace with or without a coaxial contractor. The result of the present CFD analysis showed that the entrainment mass flow rate without a coaxial contractor had 18% larger than that with a coaxial contractor when the mixed gas outlet pressure was ambient pressure. On the other hand, if the outlet pressure increased, the mass flow rate with a contractor was larger than that without a contractor. It could be analysed by the entrainment driving force composed with the nozzle throat pressure, inlet and outlet pressures and flow cross sectional area.
Keywords
MILD combustion; coanda nozzle; coaxial contractor; entrainment mass flow rate; entrainment driving force; mixed gas outlet pressure;
Citations & Related Records
Times Cited By KSCI : 3  (Citation Analysis)
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1 T. plessing, N. Peters, J.G. Wunning, "Laseroptical investigation of highly preheated combustion with strong exhaust gas recirculation", 27 Symp (Int) Combustion, 3197-3204, (1998)
2 J.A. Wuuning and J.G. Wunning, "Flameless oxidation to reduce thermal NO-formation", Prog. Energy Combust.Sci., vol.23, 81-97, (1997)   DOI   ScienceOn
3 M. Katsuki, T.Hasegawa, "The science of technology of combustion in highly preheated air", 27 Symp (Int) Combustion, 3135-3146, (1998)
4 A. Cavaliere, M. De Joannon, R. Ragucci, "Mild combustion of high temperature reactants", 2nd International Symposium on High Temperature Air Combustion, (1999)
5 Frazan, H., Maringo, G. J., Riggs, J. D., Yagiela, A. S. and Newell, R. J., "Reburning with Powder River Basin Coal to Achieve $SO_2\;an\;NO_x$ Compliance", Proc. of the Power - Gen Sixth International Conference, Dallas, 175-187, (1993)
6 Ji Soo Ha, Tae Kwon Kim and Sung Hoon Shim, "A numerical study of the air fuel ratio effect on the combustion characteristics in a MILD combustor", Korean Society of Environmental Engineers, Vol. 32, No. 6, 587-592, (2010)   과학기술학회마을
7 Tae Kwon Kim, Sung Hoon Shim, Hyuk Sang Chang and Ji Soo Ha, "A numerical study of the combustion characteristics in a MILD combustor with the change of the fuel and air nozzle position and air mass flow rate", Korean Society of Environmental Engineers, Vol. 33, No. 5, 325-331, (2011)   과학기술학회마을   DOI
8 Sung Hoon Shim and Ji Soo Ha, "A study on the flow entrainment characteristics of a coaxial nozzle used in a MILD combustor with the change of nozzle position and flow condition", Korean Society of Environmental Engineers, Vol. 34, No. 2, 103-108, (2012)   과학기술학회마을   DOI
9 S.V. Patankar, Numerical Heat Transfer and Fluid Flow, McGraw Hill Book, New York, (1980)