WSGG correlations based on HITEMP2010 for computation of thermal radiation in non-isothermal, non-homogeneous H 2 O/CO 2 mixtures Leonardo J. Dorigon a , Gustavo Duciak a , Rogério Brittes a , Fabiano Cassol a , Marcelo Galarça b , Francis H.R. França a,⇑ a Department of Mechanical Engineering, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil b Federal Institute of Rio Grande do Sul, Rio Grande, RS, Brazil article info Article history: Received 8 February 2013 Received in revised form 7 April 2013 Accepted 5 May 2013 Keywords: Radiation heat transfer Gas model WSGG LBL HITEMP2010 abstract In this study, new coefficients for the weighted-sum-of-gray-gas (WSGG) model are proposed based on the up-to-date HITEMP2010 database. The coefficients are determined for gas mixtures of water vapor and carbon dioxide with partial pressure (or molar concentration) ratios equal to 1.0 and 2.0, represent- ing typical products of the combustion of fuel oil and methane. The correlations are valid for pressure path-lengths ranging from 0.001 atm m to 10 atm m, and for temperatures varying between 400 K and 2500 K. The WSGG model with the new coefficients are applied to the solution of the radiation heat trans- fer in non-isothermal, non-homogeneous gas mixtures, which are then compared with benchmark line- by-line solutions to access the accuracy of the model for a few illustrative test cases. Results show that, in spite of its simplicity in comparison to modern gas models, the WSGG model is still a competitive alter- native to provide fast but reliable solutions of radiation heat transfer in non-uniform media. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Radiation in participating medium continues to receive con- stant attention due to its importance in a variety of phenomena, from characterization of stars and atmospheric radiation to indus- trial applications. Particularly in combustion processes, radiation is generally the dominant heat transfer mode. However, reliable computation of gas radiation in combustion modeling is still a challenging task, since it involves strong variations in the temper- ature and concentrations of the absorbing-emitting species. An- other reason is the highly complex behavior of the radiative properties of participating gases, which are represented by dozens or hundreds of thousands of spectral lines that vary strongly, rap- idly over the wavenumber. Not surprisingly, development of accu- rate, efficient models for the spectral integration of the radiative heat transfer is one of the most active areas in the thermal radia- tion field. One important advance in the modeling of radiation in partici- pating gas was the establishment in the past century of high-reso- lution spectral database that provide spectroscopic parameters to generate the transition lines. Perhaps the most widely employed databases are HITRAN, built at a reference temperature of 296 K for atmospheric applications, and HITEMP, which was established for high temperature applications, and includes combustion gases such as H 2 O, CO 2 , CO and OH. These databases are periodically up- dated and expanded. Recently, HITEMP2010 [1] was released as a solid improvement of previous versions, expanding the number of transition lines (111 million transitions for H 2 O with a spectral coverage of 0–30,000 cm 1 , and of 11 million transitions for CO 2 with a spectral coverage of 258–9648 cm 1 ), and also allowing for application in temperatures up to 4000 K. HITEMP2010 has been reported in [2,3] to provide the most accurate results in comparison with the other available databases. This makes HI- TEMP2010 arguably the best source of information to date for the development of spectral models for application in high temper- ature conditions. The simplest spectral model is the gray gas, in which the absorption coefficient is assumed uniform over the spectrum. Mak- ing use of the spectral database, the most common approach is to compute the gray gas absorption as an average of the spectral absorption coefficient weighted by the blackbody emission fraction at the respective wavelength [4]. This approach permits a correct computation of local emission in the gas, but in general fails to cor- rectly evaluate local absorption. For this reason, gray gas is of little reliability in the computation of radiation heat transfer in partici- pating gases [5]. The weighted-sum-of-gray-gas (WSGG) model [6] represents the spectrum with a few gray gases that occupy certain portions of the spectrum plus the transparent windows. Although the model was first proposed for application with the zonal method, it was 0017-9310/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2013.05.010 ⇑ Corresponding author. Tel.: +55 51 3308 3360; fax: +55 51 3308 3355. E-mail address: frfranca@mecanica.ufrgs.br (F.H.R. França). International Journal of Heat and Mass Transfer 64 (2013) 863–873 Contents lists available at SciVerse ScienceDirect International Journal of Heat and Mass Transfer journal homepage: www.elsevier.com/locate/ijhmt