A database of narrow-band parameters for fuels commonly encountered in fire applications

Abstract

The objective of this paper is to derive narrow band (NB) parameters for the Malkmus statistical narrow band model from the medium resolution transmission measurements carried out at NIST (Wakatsuki et al., Proc. Combust. Inst., vol. 31, 2007, pp. 2573–2580) up to about 1000K for nine fuels commonly encountered in fire applications, namely methane, methanol, ethane, ethylene, propane, propylene, heptane, methyl methacrylate and toluene. These NB parameters can be used to generate a database of NB k-distributions of these fuels in order to apply the k-distribution methods to model their contributions to radiative heat transfer. The accuracy of this NB database, the EM2C NB database for methane (Perrin and Soufiani, JQSRT, vol. 103, 2007, pp. 3–13), and HITRAN 2012 for methane, methanol, ethane, and ethylene is assessed by comparison with the measured medium resolution transmissivities and spectrally-integrated radiative properties. Results show that the EM2C database is the most accurate for methane over the entire range of the temperature and the fuel partial pressure path length considered. The line parameters in HITRAN 2012 are not available for some important bands of methanol, ethane and ethylene and this spectroscopic database cannot be used with confidence above 600K. The Malkmus narrow band database derived in the present study is found to reproduce spectrally-integrated radiative properties with error less than 20%, which suggests that it can be used for engineering applications. Finally, applications to radiation calculations along lines of sight with methane concentrations and temperatures representative of pool fires show that both the present Malkmus narrow band and the NIST databases can predict accurately the radiative intensity for small scale pool fires where as discrepancies of the order of 30% are expected in the case of methane pool fires with a heat release rate of 176kW.