Radiative heat transfer in the core of axisymmetric pool fires – I: Evaluation of approximate radiative property models

• Published in: International journal of thermal sciences Vol. 84; no. 84; pp. 104 - 117
• Main Authors: Consalvi, J.L., Liu, F.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Masson SAS 01.10.2014; Elsevier
• Subjects: Absorption coefficient; Applied sciences; Axisymmetric; Combustion of gaseous fuels; Combustion. Flame; Correlation; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fuel rich core; Gas radiative property models; k-Distributions; Line-by-line model; Mathematical analysis; Mathematical models; Methane; Physics; Pool fire; Pool fires; Radiation; Radiative heat transfer; Theoretical studies. Data and constants. Metering; Line-by-line model; Gas radiative property models; Pool fire; Fuel rich core; Radiation; k-Distributions; Methane; Radiative properties; Combustion; Radiative transfer; Modeling; Heat transfer
• DOI: 10.1016/j.ijthermalsci.2014.04.018
• ISSN: 1290-0729

Radiative heat transfer calculations are conducted in two laboratory-scale axisymmetric methane pool fires generated on a burner of 0.38 m diameter with heat release rates (HRR) of 34 and 176 kW by using the ‘exact’ Line-By-Line (LBL) method, the narrow band correlated-k (NBCK) model, the full-spectrum correlated-k (FSCK) model, the multi-scale full-spectrum k-distribution (MSFSK) model, and a grey wide-band model (WBM). For each radiative model the corresponding absorption coefficients for carbon dioxide, water vapor, carbon monoxide and methane are generated from the same high-resolution spectroscopic database. Model results show that the contribution of carbon monoxide can be neglected whereas that of methane increases with HRR. In addition, the grey approximation for soot holds for these weakly sooting flames. Comparisons with LBL solutions show that WBM fails to predict accurately the radiative heat transfer through the fuel rich core. The FSCK model presents the best compromise in terms of accuracy and computational efficiency for the 34 kW pool fire. However, significant discrepancies are observed for the 176 kW pool fire where the strong attenuation of radiation by methane invalidates the ‘correlated’ assumption of the absorption coefficient. MSFSK and NBCK models provide very accurate predictions, with the MSFSK model being more efficient when overlap parameters are tabulated as a function of temperature and composition. •Radiative heat transfer calculations within the rich core of methane pool fires.•Assessment of the contributions of methane and carbon monoxide.•Assessment of the approximation of grey soot in weakly sooting pool fires.•Assessment of NBCK, FSCK, MSFSK and WBM models by comparison with LBL solutions.