THERMAL SCIENCE

International Scientific Journal

Thermal Science - Online First

online first only

Numerical assessment of the effect of inflow turbulators on the thermal behavior of a combustion chamber

ABSTRACT
This work numerically investigates the effects of turbulators at the air and fuel (methane) inlets on the thermal behavior of a combustion chamber. Conservation equations for mass, momentum, energy, gaseous chemical species, soot, and temperature fluctuation variance in cylindrical axysimmetric coordinates were solved using the finite volume method. Chemical reaction rates were computed through the Arrhenius-Magnussen model, with two-step combustion reaction. The turbulence closure model, to compute the turbulent viscosity, was the standard κ-ε. The modeling of turbulence-radiation interactions (TRI) considered the absorption coefficient-temperature correlation and the temperature self-correlation. The radiative heat source was calculated using the discrete ordinates method, considering the weighted-sum-of-gray-gases (WSGG) model with the superposition method to compute the radiation from the gaseous species and soot. The effect of inlet turbulators was studied by varying the turbulence intensity of both inlet streams (air and fuel), encompassing mild to severe turbulators (TI = 3%, 6%, 15%, 20%). The results showed that temperature and radiative heat source fields, and heat transfer rates on the chamber wall and radiative fraction were importantly affected by the different turbulators intensities (e.g. radiative fraction was increased from 20.6% to 32.8% when the turbulence intensity was varied from 3% to 20%). Comparisons of results obtained when TRI modeling was neglected in relation to results obtained when TRI modeling was computed showed that TRI influenced the thermal field (temperature and radiative exchange) in a similar way independently of the turbulator intensity (e.g. radiative fraction decreased 20% when TRI modeling was neglected, for both turbulators intensities).
KEYWORDS
PAPER SUBMITTED: 2018-11-19
PAPER REVISED: 2019-07-24
PAPER ACCEPTED: 2019-08-02
PUBLISHED ONLINE: 2019-09-15
DOI REFERENCE: https://doi.org/10.2298/TSCI181119323B
REFERENCES
  1. Coelho, P. J., Numerical simulation of the interaction between turbulence and radiation in reactive flows, Progress in Energy and Combustion Science, 33 (2007), pp. 311-383
  2. Darbandi, M., Ghafourizadeh, M., Numerical study of inlet turbulators effect on the thermal characteristics of a jet propulsion-fueled combustor and its hazardous pollutants emission, ASME Journal of Heat Transfer, 139 (2017), pp. 061201-1-061201-12
  3. Saqr, K. M., et al., Effect of free stream turbulence on NOx and soot formation in turbulent diffusion CH4-air flames, Internat Communic in Heat and Mass Transfer, 37 (2010), pp. 611-617
  4. Ilbas, M., The effect of thermal radiation and radiation models on hydrogen-hydrocarbon combustion modeling, International Journal of Hydrogen Energy, 30 (2005), pp. 1113-1126
  5. Sadiki, A., et al., Modeling and simulation of effects of turbulence on vaporization, mixing and combustion of liquid-fuel sprays, Flow, Turbulence and Combustion, 75 (2005), pp. 105-130
  6. Garréton, D., Simonin, O., Final results. In: Proceedings of the 1th workshop of aerodynamics of steady state combustion chambers and furnaces, 25 (1994), pp. 29-35
  7. Centeno, F. R., et al., The influence of gas radiation on the thermal behavior of a 2D axisymmetric turbulent non-premixed methane-air flame, Energy Conv and Managem, 79 (2014), pp. 405-414
  8. Magel, H. C., et al., Modeling of hydrocarbon and nitrogen chemistry in turbulent combustor flows using detailed reaction mechanisms, In: Proceedings of the 3rd workshop on modeling of chemical reaction systems, 1996.
  9. Silva, C. V., et al., Analysis of the turbulent, non-premixed combustion of natural gas in a cylindrical chamber with and without thermal radiation, Combustion Science and Technology, 179 (2007), pp. 1605-1630
  10. Centeno, F. R., et al., Application of the WSGG model for the calculation of gas-soot radiation in a turbulent non-premixed methane-air flame inside a cylindrical combustion chamber, International Journal of Heat and Mass Transfer, 93 (2016), pp. 742-753
  11. Centeno, F.R., et al., Comparison of different WSGG correlations in the computation of thermal radiation in a 2D axisymmetric turbulent non-premixed methane-air flame, Journal of the Brazilian Society of Mechanical Sciences and Engineering, 35(4) (2013), pp. 419-430
  12. Patankar, S. V., Numerical heat transfer and fluid flow, Hemisphere, Washington, DC, 1980
  13. Eaton, A. M., et al., Components, formulations, solutions, evaluations and applications of comprehensive combustion models, Prog in Energy and Comb Science, 25 (1999), pp. 387-436
  14. Turns, S. R., An introduction to combustion: concepts and applications, McGraw-Hill, 2000
  15. Magnussen, B. F., Hjertager, B. H., On mathematical models of turbulent combustion with special emphasis on soot formation and combustion, In: Proceedings of the 16th symposium (international) on combustion - The Combustion Institute, 1977, pp. 719-729
  16. Khan, I. M., Greeves, G., A method for calculating the formation and combustion of soot in diesel engines, In: Afgan and Beer ed, Heat Transfer in Flames, chapt 25. Scripta, Washington DC, 1974
  17. Dorigon, L. J., et al., WSGG correlations based on HITEMP 2010 for computation of thermal radiation in non-isothermal, non-homogeneous H2O/CO2 mixtures, International Journal of Heat and Mass Transfer, 64 (2013), pp. 863-873
  18. Cassol, F., et al., Application of the weighted-sum-of-gray-gases-model for media composed of arbitrary concentrations of H2O, CO2 and soot, Int J of Heat and Mass Transf, 79 (2014), 796-806
  19. Centeno, F.R., et al., Evaluation of the WSGG model against line-by-line calculation of thermal radiation in a non-gray sooting medium representing an axisymmetric laminar jet flame, International Journal of Heat and Mass Transfer, 124 (2018), pp. 475-483
  20. Barve, V.V., Computations of strongly forced laminar cold-flow jets and methane-air diffusion flames, Ph. D. thesis, The University of Texas at Austin, USA, 2006
  21. Harmandar, S., Selçuk, N., The method of lines solution of discrete ordinates method for radiative heat transfer in cylindrical enclosures, Journal of Quantitative Spectroscopy and Radiative Transfer, 84 (2004), pp. 395-407
  22. Paul, S. C., Paul, M. C., Radiative heat transfer during turbulent combustion process, International Communications in Heat and Mass Transfer, 37 (2010), pp 1-6
  23. Snegirev, A. Y., Statistical modeling of thermal radiation transfer in buoyant turbulent diffusion flames, Combustion and Flame, 136 (2004), pp. 51-71
  24. Fraga, G.C., et al., Evaluation and optimization-based modification of a model for the mean radiative emission in a turbulent non-reactive flow, International Journal of Heat and Mass Transfer, 114 (2017), pp. 664-674
  25. Fraga, G.C., et al., On the individual importance of temperature and concentration fluctuations in the turbulence-radiation interaction in pool fires, Fire Safety Journal, 108 (2019), pp. 1079-1089
  26. Kabashnikov, V. P., Kmit, G. I., Influence of turbulent fluctuations on thermal radiation, Journal of Applied Spectroscopy, 31 (1979), pp. 963-967
  27. Li, G., Modest, M.F., Application of composition PDF methods in the investigation of turbulence-radiation interactions, J of Quant Spectr and Radiat Transf, 73 (2002), pp. 461-472
  28. Li, G., Modest, M. F., Importance of turbulence-radiation interactions in turbulent reacting flows, In: ASME International Mechanical Engineering Congress and Exhibition, 2002, Louisiana, USA
  29. Habibi, A., et al., Turbulence radiation interaction in Reynolds-averaged Navier-Stokes simulations of nonpremixed piloted turbulent laboratory-scale flames, Combustion and Flame, 151 (2007), pp. 303-320
  30. Gupta, A., et al., Turbulence-radiation interactions in large-eddy simulations of luminous and nonluminous nonpremixed flames, Proceed. of the Combustion Institute, 34 (2013), pp. 1281-88
  31. Roache, P. J., Perspective: a method for uniform reporting of grid refinement studies, ASME Journal of Fluid Engineering, 116 (1994), pp. 405-413
  32. Celik, I. B., et al., Procedure for estimation and reporting of uncertainty due to discretization in CFD applications, ASME Journal of Fluid Engineering, 130 (2008), pp. 078001-1-078001-4
  33. Caetano, N.R., et al., A comparison of experimental results of soot production in laminar premixed flames, Open Engineering, 5(1) (2015), pp. 213-219