THERMAL SCIENCE

International Scientific Journal

Nenad Đ Crnomarković

,

Srđan V. Belošević

,

Ivan D. Tomanović

,

Aleksandar R. Milićević

,

Andrijana D. Stojanović

,

Dragan R. Tucaković

INFLUENCE OF THE TEMPERATURE FLUCTUATIONS ON THE FLAME TEMPERATURE AND RADIATIVE HEAT EXCHANGE INSIDE A PULVERIZED COAL-FIRED FURNACE

ABSTRACT
In this paper, influence of the temperature fluctuations, (as a version of turbulence-radiation interaction), on the flame temperature and radiative heat exchange inside the pulverized coal-fired furnace was investigated. The radiative heat exchange was solved by the Hottel zonal model. The influence of the temperature fluctuation was studied for three values of the extinction coefficient of the flame: 0.3 m–1, 1.0 m–1, and 2.0 m–1. The investigation was conducted for the relative temperature fluctuations obtained by solving the transport equation for the temperature variance, and for four constant values of the relative temperature fluctuations (0.0, 0.1, 0.15, and 0.2). The maximal values of the mean temperature fluctuations and relative temperature fluctuations were obtained in the region close to the burners. The decrease of the flame temperature of about 100 K was obtained in the hottest region, for every extinction coefficient. An increase in the mean wall flux was found to be on the order of several percents, compared to the case without the temperature fluctuations. When the temperature variance was calculated, the mean relative temperature fluctuations were approximately 15%, for every extinction coefficient. The mean wall fluxes increased and flame temperature at the furnace exit plane decreased with the increase in the relative temperature fluctuations. The selected indicators of the furnace operation, such as the mean wall flux and mean flame temperature at the furnace exit plane, obtained for the calculated temperature variance, were close to the values predicted for the constant relative temperature fluctuation of 15%.
KEYWORDS
furnace, pulverized coal, numerical investigation, turbulence radiation interaction, temperature fluctuation, flame temperature, wall flux
PAPER SUBMITTED: 2023-06-09
PAPER REVISED: 2023-07-02
PAPER ACCEPTED: 2023-07-14
PUBLISHED ONLINE: 2023-08-05
DOI REFERENCE: https://doi.org/10.2298/TSCI230609173C
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2023, VOLUME 27, ISSUE Issue 6, PAGES [4539 - 4549]
REFERENCES
  1. Modest, M. F., Mazumder, S., Radiative Heat Transfer, Academic Press, New York, USA, 2023
  2. Coelho, P. J, Numerical Simulation of the Interaction between Turbulence and Radiation in Reactive Flows, Progress in Energy and Combustion Science, 33 (2007), 4, pp. 311-383
  3. Viskanta, R., Radiative Transfer in Combustion Systems: Fundamentals and Applications, Begell House, New York, USA, 2005
  4. Li, G., Modest, M. F., Importance of Turbulence-Radiation Interactions in Turbulent Diffusion Jet Flames, Journal of Heat Transfer, 125 (2003), 5, pp. 831-838
  5. 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), 1-2, pp. 303-320
  6. Coelho, P. J, Evaluation of a Model for Turbulence/Radiation Interaction in Flames Using a Differential Solution Method of the Radiative Transfer Equation, in: Heat Transfer 2000 (Ed. J. Taine) Edition Elsevir, Paris, 2002, Vol 1, pp. 657-662
  7. Yi, Z., et al., Study of the Non-Gray-TRI Effect on the Turbulent Methane Combustion under O2/CO2 Atmosphere, Applied Thermal Engineering, 130 (2018), Feb., pp. 449-457
  8. Centeno, R. R., et al., The Influence of Gas Radiation on the Thermal Behavior of a 2D Axisymmetric Turbulent Non-Premixed Methane-Air Flame, Energy Conversion and Management, 79 (2014), Mar., pp. 405-414
  9. Yang, X., et al., Numerical Analysis of Turbulence Radiation Interaction Effects on Radiative Heat Transfer in a Swirling Oxyfuel Furnace, International Journal of Heat and Mass Transfer, 141 (2019), Oct., pp. 1227-1237
  10. Snegirev, A. Yu., Statistical Modeling of Thermal Radiation Transfer in Buoyant Turbulent Diffusion Flames, Combustion and Flame, 136 (2004), 1-2, pp. 51-71
  11. Lou, C., et al., Measurements of the Flame Emissivity and Radiative Properties of Particulate Medium in Pulverized-Coal-Fired Boiler Furnaces by Image Processing of Visible Radiation, Proceedings of the Combustion Institute, 31 (2007), 2, pp. 2771-2778
  12. Yin, C., On Gas and Particle Radiation in Pulverized Fuel Combustion Furnaces, Applied Energy, 157 (2015), Nov., pp. 554-561
  13. Crnomarkovic, N. Dj, et al., Influence of Application of Hottelʼs Zonal Model and Six-Flux Model of Thermal Radiation on Numerical Simulations Results of Pulverized Coal Fired Furnace, Thermal Science, 16 (2012), 1, pp. 271-282
  14. Crnomarkovic, N., et al., Influence of Forward Scattering on Prediction of Temperature and Radiation Fields inside the Pulverized Coal Furnace, Energy, 45 (2012), 1, pp. 160-168
  15. Crnomarkovic, N., et al., Radiative Heat Exchange inside the Pulverized Lignite Fired Furnace for the Gray Radiative Properties with Thermal Equilibrium Between Phases, International Journal of Thermal Sciences, 85 (2014), Nov., pp. 21-28
  16. Belosevic, S., et al., Numerical Prediction of Pulverized Coal Flame in Utility Boiler Furnaces, Energy & Fuels, 23 (2009), 11, pp. 5401-5412
  17. Versteeg, H. K., Malalasekera, W., An Introduction to Computational Fluid Dynamics, Pearson Education Limited, Harlow, UK, 2007
  18. Crnomarkovic, N., et al., New Application Method of the Zonal Model for Simulations of Pulverized Coal-Fired Furnaces Based on Correction of Total Exchange Areas, International Journal of Heat and Mass Transfer, 149 (2020), 119192
  19. Singer, J. G., Combustion Fossil Power, Combustion Engineering, Stamford, Conn., USA, 1991
  20. Kaye, G. W. C., Laby, T. H., Tables of Physical and Chemical Constants, Longman, London, 1995
  21. Boow, J., Goard, P. R. C., Fireside Deposits and Their Effect on Heat Transfer in a Pulverized-Fuel- Fired Boiler. Part III: The Influence of the Physical Characteristics of the Deposit on Its Radiant Emittance and Effective Thermal Conductance, Journal of the Institute of Fuel, 42 (1969), 346, pp. 412- 419
  22. Crnomarkovic, N. DJ., et al., Numerical Determination of the Impact of the Ash Deposit on the Furnace Walls to the Radiative Heat Exchange inside the Pulverized Coal Fired Furnace, Proceedings, International Conference Power Plants, Zlatibor, Serbia, 2014, pp. 1-12
  23. Sijercic, M., Matematičko Modeliranje Kompleksnih Turbulentnih Transportnih Procesa (Mathematical Modeling of Complex Turbulent Transport Processes - in Serbian), Yugoslav Society of Thermal Engineers, Vinca Institute of Nuclear Sciences, Belgrade, 1998
  24. Tucker, R. J., Direct Exchange Areas for Calculating Radiation Transfer in Rectangular Furnaces, Journal of Heat Transfer, 108 (1986), 3, pp. 707-710
  25. Hottel, H. C., Sarofim, A. F., Radiative Transfer, McGraw-Hill Book Company, New York, USA, 1967
  26. Mechi, R., et al., Extension of the Zonal Method to Inhomogeneous Non-Gray Semi-Transparent Medium, Energy, 35 (2010), 1, pp. 1-15
  27. Boardman, R., Smoot. L. D., Pollutant Formation and Control, in Fundamentals of Coal Combustion, For Clean and Efficient Use, (Ed. L.D. Smoot), Coal Science and Technology 20, Elsevier, New York, USA, 1993, pp. 433-509
PDF VERSION [DOWNLOAD]
Influence of the temperature fluctuations on the flame temperature and radiative heat exchange inside a pulverized coal-fired furnace

© 2024 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International licence