A new weighted-sum-of-gray-gases model for oxy-combustion scenarios

Abstract

SUMMARY A new weighted‐sum‐of‐gray gases (WSGG) model that is based on the statistical narrow band model (SNB) RADCAL is proposed for use in computational fluid dynamic (CFD) simulations of air and oxy‐combustion. When employed in conjunction with the discrete ordinates (DO) method, the model predictions compare well against line‐by‐line benchmark data that have been made available recently that are based on the latest spectroscopic databases. Furthermore, the model compares well against the EM2C SNB model calculations that have served as benchmark data in three‐dimensional geometries. Radiative transfer calculations in these prototypical problems therefore confirm recent experimental observations that SNB RADCAL and EM2C SNB serve as good model databases to develop approximate radiative property models. To achieve an optimum balance of speed and accuracy in computationally intensive CFD simulations, non‐gray formulations of the WSGG model are also employed with the P1 model and solutions are compared against those generated by the DO model. While the P1 model gave favorable comparisons when cold, black walls were present, the errors in the surface incident radiative flux predictions increased in the presence of hot, reflecting walls. Finally, in fully coupled simulations of natural gas combustion under air‐firing and oxy‐firing modes, the predicted incident radiative flux profiles were distinctly different between the gray and non‐gray calculations at regions of high temperature gradients, while the centerline temperature predictions were comparatively unaffected. The effects of turbulence radiation interactions were also accounted for through the temperature self‐correlation term. However, the magnitudes of the temperature fluctuations were small and localized within this furnace and did not significantly alter our predictions. Copyright © 2012 John Wiley & Sons, Ltd.

Effects of total pressure on non-grey gas radiation transfer in oxy-fuel combustion using the LBL, SNB, SNBCK, WSGG, and FSCK methods

“…Later, Johansson et al improved the WSGG model for gas radiation in oxyfuel combustion by allowing the weight factors to depend on both temperature and the molar ratio of H 2 O to CO 2 and the absorption coefficients to vary with the molar ratio [14]. Krishnamoorthy proposed another set of WSGG model parameters for oxy-fuel applications [15] based on the total emissivity from RADCAL [16], which is also a SNB model but using different parameters. Kangwanpongpan et al proposed another set of WSGG model parameters for oxy-fuel combustion applications [17] by fitting the total gas emissivity from LBL calculations using the HITEMP2010 spectral database [18].…”

A full spectrum k-distribution based weighted-sum-of-gray-gases model for oxy-fuel combustion

“…These parameters were computed from the emissivity based on correlations in the Perry's Chemical Engineering Handbook [20]. In a second paper, Krishnamoorthy et al [21] improved the WSGG model based on the SNB model RADCAL. Rehfeldt et al [22] obtained the new parameters of WSGG model based on the EWB model.…”

Combustion and heat transfer characteristics of co-firing biomass and coal under oxy-fuel condition

“…The kinetic parameters of reactions (11) to (15) could be found in Andersen et al 13 4 | RESULTS AND DISCUSSION…”

“…Some modeling strategies were refined for oxy‐fuel combustion because the combustion atmosphere has been changed. For instance, several researchers proposed modified models to simulate the radiative heat transfer process . For gas phase combustion, Westbrook and Dryer 2‐step mechanism and Jones and Lindstedt 4‐step mechanism were improved and investigated by Andersen et al Char combustion and gasification processes were also studied .…”

“…For instance, several researchers proposed modified models to simulate the radiative heat transfer process. [10][11][12] For gas phase combustion, Westbrook and Dryer 2-step mechanism and Jones and Lindstedt 4-step mechanism were improved and investigated by Andersen et al 13 Char combustion and gasification processes were also studied. [14][15][16] Comparatively, the combustion atmosphere has little influence on devolatilization process.…”