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Laser-induced incandescence measurements of soot in turbulent pool fires

Journal Article · · Applied Optics
DOI:https://doi.org/10.1364/AO.50.000A49· OSTI ID:22036576

We present what we believe to be the first application of the laser-induced incandescence (LII) technique to large-scale fire testing. The construction of an LII instrument for fire measurements is presented in detail. Soot volume fraction imaging from 2 m diameter pool fires burning blended toluene/methanol liquid fuels is demonstrated along with a detailed report of measurement uncertainty in the challenging pool fire environment. Our LII instrument relies upon remotely located laser, optical, and detection systems and the insertion of water-cooled, fiber-bundle-coupled collection optics into the fire plume. Calibration of the instrument was performed using an ethylene/air laminar diffusion flame produced by a Santoro-type burner, which allowed for the extraction of absolute soot volume fractions from the LII images. Single-laser-shot two-dimensional images of the soot layer structure are presented with very high volumetric spatial resolution of the order of 10{sup -5} cm{sup 3}. Probability density functions of the soot volume fraction fluctuations are constructed from the large LII image ensembles. The results illustrate a highly intermittent soot fluctuation field with potentially large macroscale soot structures and clipped soot probability densities.

OSTI ID:
22036576
Journal Information:
Applied Optics, Journal Name: Applied Optics Journal Issue: 4 Vol. 50; ISSN 0003-6935; ISSN APOPAI
Country of Publication:
United States
Language:
English