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Models for gaseous radiative heat transfer applied to oxy-fuel conditions in boilers

Robert Johansson (Institutionen för energi och miljö, Energiteknik) ; Klas Andersson (Institutionen för energi och miljö, Energiteknik) ; Bo Leckner (Institutionen för energi och miljö, Energiteknik) ; Henrik Thunman (Institutionen för energi och miljö, Energiteknik)
International Journal of Heat and Mass Transfer (0017-9310). Vol. 53 (2010), 1-3, p. 220-230.
[Artikel, refereegranskad vetenskaplig]

Models of gas radiation properties have been evaluated for conditions relevant to oxy-fired boilers, characterized by larger pressure path-lengths and possibly different ratios of H2O/CO2 compared to air-fired boilers. Statistical narrow band (SNB) models serve as reference. The other radiation models tested are the weighted-sum-of-grey-gases model, the spectral line-based weighted-sum-of-grey-gases model and two grey-gas approximations. The range of validity of the existing coefficients of the weighted-sum-of-grey-gases model is limited, and new coefficients have therefore been determined to cover the conditions of interest. Several assumed test cases, involving both uniform and non-uniform paths, have been studied to evaluate the accuracy of the models. Comparisons with experimental data are also included. The results show that a grey approximation can give accurate wall fluxes, but at the expense of errors in the radiative source term. The weighted-sum-of-grey-gases model with the new coefficients yields predictions within 20% of those of the reference model in most cases, while the spectral line-based weighted-sum-of-grey-gases model usually gives results within 10%. There are, however, discrepancies between the SNB models at high temperatures. The weighted-sum-of-grey-gases model with its low computational cost is recommended for computationally demanding applications where predictions of both wall fluxes and the radiative source term are important.

Nyckelord: Gas radiation, Modelling, CFD, Oxy-fuel

Denna post skapades 2009-12-22. Senast ändrad 2016-08-15.
CPL Pubid: 104749


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Institutioner (Chalmers)

Institutionen för energi och miljö, Energiteknik (2005-2017)


Annan kemiteknik

Chalmers infrastruktur