Advertisement

Modelling paradigms for MILD combustion

  • Y. Minamoto
  • N. Swaminathan
Article

Abstract

Three-dimensional Direct Numerical Simulation (DNS) data of methane-air MILD combustion is analysed to study the behaviour of MILD reaction zones and to identify a suitable modelling paradigm for MILD combustion. The combustion kinetics in the DNS was modelled using a skeletal mechanism including non-unity Lewis number effects. The reaction zones under MILD conditions are highly convoluted and contorted resulting in their frequent interactions. This leads to combustion occurring over a large portion of the computational volume and giving an appearance of distributed combustion. Three paradigms, standard flamelets, mild flame elements (MIFEs) and PSR, along with a presumed PDF model are explored to estimate the mean and filtered reaction rate in MILD combustion. A beta function is used to estimate the presumed PDF shape. The variations of species mass fractions and reaction rate with temperature computed using these models are compared to the DNS results. The PSR-based model is found to be appropriate, since the conditional averages obtained from the DNS agree well with those obtained using the PSR model. The flamelets model with MIFEs gives only a qualitative agreement because it does not include the effects of reaction zone interactions.

Keywords

MILD combustion Flameless combustion Direct numerical simulation (DNS) Perfectly stirred reactor (PSR) Presumed PDF LES RANS Modelling 

Notes

Acknowledgments

YM acknowledges the financial support of Nippon Keidanren and Cambridge Overseas Trust. EPSRC support is acknowledged by NS. This work made use of the facilities of HECToR, the UK’s national high-performance computing service, which is provided by UoE HPCx Ltd at the University of Edinburgh, Cray Inc and NAG Ltd, and funded by the Office of Science and Technology through EPSRCs High End Computing Programme.

References

  1. 1.
    Aminian, J., Galletti, C., Shahhosseini, S., Tognotti, L.: Key modeling issues in prediction of minor species in diluted-preheated combustion conditions. Appl. Thermal Eng. 31, 3287–3300 (2011)CrossRefGoogle Scholar
  2. 2.
    Buschmann, A., Dinkelacker, F., Schäfer, T., Wolfrum, J.: Measurement of the instantaneous detailed flame structure in turbulent premixed combustion. Proc. Combust. Inst. 26, 437–445 (1996)CrossRefGoogle Scholar
  3. 3.
    Cant, R.S.: SENGA2 User Guide. In: Technical Report CUED/A-THERMO/TR67. Cambridge University Engineering Department, Cambridge (2012)Google Scholar
  4. 4.
    Cavaliere, A., de Joannon, M.: Mild combustion. Progr. Energy Combust. Sci. 30, 329–366 (2004)CrossRefGoogle Scholar
  5. 5.
    Chen, J.H., Echekki, T., Kollmann, W.: The mechanism of two-dimensional pocket formation in lean premixed methane-air flames with implications to turbulent combustion. Combust. Flame 116, 15–48 (1999)CrossRefGoogle Scholar
  6. 6.
    Chen, Y.C., Peters, N., Schneemann, G.A., Wruck, N., Renz, U., Mansour, M.S.: The detailed flame structure of highly stretched turbulent premixed methane-air flames. Combust. Flame 107, 223–244 (1996)CrossRefGoogle Scholar
  7. 7.
    Christo, F.C., Dally, B.B.: Modelling turbulent reacting jets issuing into a hot and diluted coflow. Combust. Flame 142, 117–129 (2005)CrossRefGoogle Scholar
  8. 8.
    Coelho, P.J., Peters, N.: Numerical simulation of a mild combustion burner. Combust. Flame 124, 503–518 (2001)CrossRefGoogle Scholar
  9. 9.
    COSILAB: The Combustion Simulation Laboratory Version 2.0.8. Rotexo-Softpredict-Cosilab GmbH & Co. KG, Germany (2007)Google Scholar
  10. 10.
    Dally, B.B., Riesmeier, E., Peters, N.: Effect of fuel mixture on moderate and intense low oxygen dilution combustion. Combust. Flame 137, 418–431 (2004)CrossRefGoogle Scholar
  11. 11.
    Dunstan, T.D., Swaminathan, N., Bray, K.N.C., Kingsbury, N.G.: The effects of non-unity Lewis numbers on turbulent premixed flame interactions in a twin V-flame configuration. Combust. Sci. Technol. 185(6), 874–897 (2013a)CrossRefGoogle Scholar
  12. 12.
    Dunstan, T.D., Swaminathan, N., Bray, K.N.C., Kingsbury, N.G.: Flame interactions in turbulent premixed twin V-flames. Combust. Sci. Technol. 185(1), 134–159 (2013b)CrossRefGoogle Scholar
  13. 13.
    Duwig, C., Li, B., Aldén, M.: High resolution imaging of flameless and distributed turbulent combustion. Combust. Flame 159, 306–316 (2012)CrossRefGoogle Scholar
  14. 14.
    Duwig, C., Stankovic, D., Fuchs, L., Li, G., Gutmark, E.: Experimental and numerical study of flameless combustion in a model gas turbine combustor. Combust. Sci. Technol. 180(2), 279–295 (2008)CrossRefGoogle Scholar
  15. 15.
    Ertesvag, I.S., Magnussen, B.F.: A numerical study of a bluff-body stabilized diffusion flame. part 1. influence of turbulence modeling and boundary conditions. Combust. Sci. Technol. 119(1–6), 171–190 (1996a)Google Scholar
  16. 16.
    Ertesvag, I.S., Magnussen, B.F.: A numerical study of a bluff-body stabilized diffusion flame. Part 2. Influence of combustion modeling and finite-rate chemistry. Combust. Sci. Technol. 119(1–6), 191–217 (1996b)Google Scholar
  17. 17.
    Eswaran, V., Pope, S.B.: Direct numerical simulations of the turbulent mixing of a passive scalar. Phys. Fluids 31(3), 506–520 (1987)CrossRefGoogle Scholar
  18. 18.
    Galletti, C., Parente, A., Tognotti, L.: Numerical and experimental investigation of a mild combustion burner. Combust. Flame 151, 649–664 (2007)CrossRefGoogle Scholar
  19. 19.
    Hayashi, S., Mizobuchi, Y.: Utilization of hot burnt gas for better control of combustion and emissions. In: Swaminathan, N., Bray, K.N.C. (eds.) Turbulent Premixed Flames, pp. 365–378. Cambridge University Press, Cambridge (2011)CrossRefGoogle Scholar
  20. 20.
    Ihme, M., See, Y.C.: Les flamelet modeling of a three-stream mild combustor: analysis of flame sensitivity to scalar inflow conditions. Proc. Combust. Inst. 33, 1309–1317 (2012)CrossRefGoogle Scholar
  21. 21.
    Jenkins, K.W., Cant, R.S.: DNS of turbulent flame kernels. In: Knight & Sakell (eds.) Proc. Second AFOSR Conf. on DNS and LES. Rutgers University, Kluwer Academic Publishers, New Brunswick, pp. 192–202. (1999)Google Scholar
  22. 22.
    de Joannon, M., Saponaro, A., Cavaliere, A.: Zero-dimensional analysis of diluted oxidation of methane in rich conditions. Proc. Combust. Inst. 28, 1639–1646 (2000)CrossRefGoogle Scholar
  23. 23.
    Katsuki, M., Hasegawa, T.: The science and technology of combustion in highly preheated air. Proc. Combust. Inst. 27, 3135–3146 (1998)CrossRefGoogle Scholar
  24. 24.
    Krishnamurthy, N., Paul, P.J., Blasiak, W.: Studies on low-intensity oxy-fuel burner. Proc. Combust. Inst. 32, 3139–3146 (2009)CrossRefGoogle Scholar
  25. 25.
    Li, P., Mi, J.: Influence of inlet dilution of reactants on premixed combustion in a recuperative furnace. Flow Turbulence Combust. 33, 1599–1607 (2011). doi: 10.1007/s10494-011-9348-x Google Scholar
  26. 26.
    Magnussen, B.F.: On the structure of turbulence and a generalized eddy dissipation concept for chemical reaction in turbulent flow. In: 19th American Institute of Aeronautics and Astronautics Aerospace Science Meeting, pp. 1–6 (1981)Google Scholar
  27. 27.
    Medwell, P.R., Kalt, P.A.M., Dally, B.B.: Simultaneous imaging of OH, formaldehyde, and temperature of turbulent nonpremixed jet flames in a heated and diluted coflow. Combust. Flame 148, 48–61 (2007)CrossRefGoogle Scholar
  28. 28.
    Minamoto, Y.: Physical aspects and modelling of turbulent MILD combustion. PhD thesis, Department of Engineering, University of Cambridge, Cambridge. (2013)Google Scholar
  29. 29.
    Minamoto, Y., Dunstan, T.D., Swaminathan, N., Cant, R.S.: DNS of EGR-type turbulent flame in MILD condition. Proc. Combust. Inst. 34, 3231–3238 (2013a)CrossRefGoogle Scholar
  30. 30.
    Minamoto, Y., Swaminathan, N.: Scalar gradient behaviour in MILD combustion. Combust. Flame 161, 1063–1075 (2014). doi: 10.1016/j.combustflame.2013.10.005
  31. 31.
    Minamoto, Y., Swaminathan, N., Cant, R. S., Leung, T.: Morphology of reaction zones in mild and premixed combustion. Combust. Flame (2013b) (submitted)Google Scholar
  32. 32.
    Oldenhof, E., Tummers, M.J., van Veen, E.H., Roekaerts, D.J.E.M.: Role of entrainment in the stabilisation of jet-in-hot-coflow flames. Combust. Flame 158, 1553–1563 (2011)CrossRefGoogle Scholar
  33. 33.
    Orsino, S., Webber, R., Bollettini, U.: Numerical simulation of combustion of natural gas with high-temperature air. Comb. Sci. Technol. 170(1), 1–34 (2001)CrossRefGoogle Scholar
  34. 34.
    Özdemir, Í.B., Peters, N.: Characteristics of the reaction zone in a combustor operating at MILD combustion. Exp. Fluids 30, 683–695 (2001)CrossRefGoogle Scholar
  35. 35.
    Parente, A., Galletti, C., Tognotti, L.: A simplified approach for predicting NO formation in MILD combustion of \(\text{ CH }_{4}-{\text{ H }}_{2}\) mixtures. Proc. Combust. Inst. 33, 3343–3350 (2011)CrossRefGoogle Scholar
  36. 36.
    Peters, N.: Turbulent Combustion. Cambridge University Press, Cambridge (2000)CrossRefzbMATHGoogle Scholar
  37. 37.
    Pfadler, S., Leipertz, A., Dinkelacker, F.: Systematic experiments on turbulent premixed Bunsen flame including turbulent flux measurement. Combust. Flame 152, 616–631 (2008)CrossRefGoogle Scholar
  38. 38.
    Plessing, T., Peters, T., Wünning, J.G.: Laseroptical investigation of highly preheated combustion with strong exhaust gas recirculation. Proc. Combust. Inst. 27, 3197–3204 (1998)CrossRefGoogle Scholar
  39. 39.
    Poinsot, T., Lele, S.: Boundary conditions for direct simulations of compressible viscos flows. J. Comput. Phys. 101, 104–129 (1992)CrossRefzbMATHMathSciNetGoogle Scholar
  40. 40.
    Rogallo, R.S.: Numerical experiments in homogeneous turbulence. NASA TM, p. 81315 (1981)Google Scholar
  41. 41.
    Smooke, M.D., Giovangigli, V.: Formulation of the Premixed and Nonpremixed Test Problems. In: Smooke, M.D. (ed.) Reduced Kinetic Mechanisms and Asymptotic Approximations for Methane-Air Flames, vol. 384, pp. 1–28. Springer, New York (1991)CrossRefGoogle Scholar
  42. 42.
    Suzukawa, Y., Sugiyama, S., Hino, Y., Ishioka, M., Mori, I.: Heat transfer improvement and NOx reduction by highly preheated air combustion. Energy Convers. Manag 38(10–13), 1061–1071 (1997)CrossRefGoogle Scholar
  43. 43.
    Swaminathan, N., Bilger, R.W., Cuenot, B.: Relationship between turbulent scalar flux and conditional dilatation in premixed flames with complex chemistry. Combust. Flame 126, 1764–1779 (2001)CrossRefGoogle Scholar
  44. 44.
    Trouvé, A., Poinsot, T.: The evolution equation for the flame surface density in turbulent premixed combustion. J. Fluid Mech. 278, 1–31 (1994)CrossRefzbMATHMathSciNetGoogle Scholar
  45. 45.
    Weber, R., Orsino, S., Lallemant, N., Verlaan, A.: Combustion of natural gas with high-temperature air and large quantities of flue gas. Proc. Combust. Inst. 28, 1315–1321 (2000)CrossRefGoogle Scholar
  46. 46.
    Wünning, J.A., Wünning, J.G.: Flameless oxidation to reduce thermal NO-formation. Prog. Energy Combust. Sci. 23, 81–94 (1997)CrossRefGoogle Scholar

Copyright information

© Indian Institute of Technology Madras 2014

Authors and Affiliations

  1. 1.Department of EngineeringCambridge UniversityCambridgeUK

Personalised recommendations