Characterization of soot properties in two-meter JP-8 pool fires.

Suo-Anttila, Jill Marie ; Jensen, Kirk A. ; Blevins, Linda Gail (Sandia National Laboratories, Livermore, CA)

Sandia National Laboratories

关键词: Optical Properties;    Heat Transfer;    Combustion-Testing.;    02 Petroleum;    Radiative Transfer.;   

DOI  :  10.2172/921745
RP-ID  :  SAND2005-0337
RP-ID  :  AC04-94AL85000
RP-ID  :  921745

美国|英语

来源: UNT Digital Library

【 摘 要 】

The thermal hazard posed by large hydrocarbon fires is dominated by the radiative emission from high temperature soot. Since the optical properties of soot, especially in the infrared region of the electromagnetic spectrum, as well as its morphological properties, are not well known, efforts are underway to characterize these properties. Measurements of these soot properties in large fires are important for heat transfer calculations, for interpretation of laser-based diagnostics, and for developing soot property models for fire field models. This research uses extractive measurement diagnostics to characterize soot optical properties, morphology, and composition in 2 m pool fires. For measurement of the extinction coefficient, soot extracted from the flame zone is transported to a transmission cell where measurements are made using both visible and infrared lasers. Soot morphological properties are obtained by analysis via transmission electron microscopy of soot samples obtained thermophoretically within the flame zone, in the overfire region, and in the transmission cell. Soot composition, including carbon-to-hydrogen ratio and polycyclic aromatic hydrocarbon concentration, is obtained by analysis of soot collected on filters. Average dimensionless extinction coefficients of 8.4 {+-} 1.2 at 635 nm and 8.7 {+-} 1.1 at 1310 nm agree well with recent measurements in the overfire region of JP-8 and other fuels in lab-scale burners and fires. Average soot primary particle diameters, radius of gyration, and fractal dimensions agree with these recent studies. Rayleigh-Debye-Gans theory of scattering applied to the measured fractal parameters shows qualitative agreement with the trends in measured dimensionless extinction coefficients. Results of the density and chemistry are detailed in the report.