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Investigation of gas and particle radiation modelling in wet oxy-coal combustion atmospheres

Kez, Vitali and Consalvi, Jean-Louis and Liu, Fengshan and Gronarz, Tim and Ströhle, Jochen and Kneer, Reinhold and Epple, Bernd (2019):
Investigation of gas and particle radiation modelling in wet oxy-coal combustion atmospheres.
In: International Journal of Heat and Mass Transfer, pp. 1026-1040, 133, ISSN 00179310, DOI: 10.1016/j.ijheatmasstransfer.2019.01.013, [Online-Edition: https://doi.org/10.1016/j.ijheatmasstransfer.2019.01.013],
[Article]

Abstract

In this study, the impact of various treatments of gas and particle radiative properties on modelling radiative heat transfer in a 2D-squared enclosure with conditions representative to the post-burner region of an oxy-coal furnace with wet flue-gas recirculation is systematically investigated. The benchmark solutions for the radiative source terms and the net wall heat fluxes are computed with a narrow-band correlated-k (NBCK) model to account for the non-gray gas radiation in conjuction with the Mie-theory to compute the particle radiative properties. Comparisons with this benchmark solution show that the use of gray Henyey-Greenstein functions obtained with the Planck-mean values for the asymmetry factors of the coal/char and ash particles is sufficient to model accurately the scattering phase functions. In addition, the use of Planck-mean values for all the particle radiative properties provides predictions within 20% of the reference solutions. On the other hand, model results show that the application of a constant refractive index for ash particles induce large discrepancies, whereas such approximation can be made for coal particles without loss of accuracy. Finally, a significant amount of computational cost can be saved with no significant loss of accuracy by considering a wide-band correlated-k model instead of the NBCK model. The full-spectrum correlated-k (FSCK) scheme proposed by Modest and Riazzi (2005) based on gray scattering coefficients and phase functions improves further the computational saving with higher mean relative errors of about 5% for the radiative source terms and net wall heat fluxes. Thus, it is concluded that the FSCK model is appropriate to model the radiative heat transfer including gas and particle radiation for engineering applications.

Item Type: Article
Erschienen: 2019
Creators: Kez, Vitali and Consalvi, Jean-Louis and Liu, Fengshan and Gronarz, Tim and Ströhle, Jochen and Kneer, Reinhold and Epple, Bernd
Title: Investigation of gas and particle radiation modelling in wet oxy-coal combustion atmospheres
Language: English
Abstract:

In this study, the impact of various treatments of gas and particle radiative properties on modelling radiative heat transfer in a 2D-squared enclosure with conditions representative to the post-burner region of an oxy-coal furnace with wet flue-gas recirculation is systematically investigated. The benchmark solutions for the radiative source terms and the net wall heat fluxes are computed with a narrow-band correlated-k (NBCK) model to account for the non-gray gas radiation in conjuction with the Mie-theory to compute the particle radiative properties. Comparisons with this benchmark solution show that the use of gray Henyey-Greenstein functions obtained with the Planck-mean values for the asymmetry factors of the coal/char and ash particles is sufficient to model accurately the scattering phase functions. In addition, the use of Planck-mean values for all the particle radiative properties provides predictions within 20% of the reference solutions. On the other hand, model results show that the application of a constant refractive index for ash particles induce large discrepancies, whereas such approximation can be made for coal particles without loss of accuracy. Finally, a significant amount of computational cost can be saved with no significant loss of accuracy by considering a wide-band correlated-k model instead of the NBCK model. The full-spectrum correlated-k (FSCK) scheme proposed by Modest and Riazzi (2005) based on gray scattering coefficients and phase functions improves further the computational saving with higher mean relative errors of about 5% for the radiative source terms and net wall heat fluxes. Thus, it is concluded that the FSCK model is appropriate to model the radiative heat transfer including gas and particle radiation for engineering applications.

Journal or Publication Title: International Journal of Heat and Mass Transfer
Volume: 133
Uncontrolled Keywords: Oxy-fuel combustion, Non-gray radiation models, NBCK, WBCK, FSCK, Particle radiation models
Divisions: 16 Department of Mechanical Engineering
16 Department of Mechanical Engineering > Institut für Energiesysteme und Energietechnik (EST)
Profile Areas
Profile Areas > Thermo-Fluids & Interfaces
Date Deposited: 02 Apr 2019 14:12
DOI: 10.1016/j.ijheatmasstransfer.2019.01.013
Official URL: https://doi.org/10.1016/j.ijheatmasstransfer.2019.01.013
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