Modeling laser-induced incandescence of soot
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Date
2007
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Springer-Verlag
Abstract
We have performed a comparison of ten models
that predict the temporal behavior of laser-induced incandescence
(LII) of soot. In this paper we present a summary of the
models and comparisons of calculated temperatures, diameters,
signals, and energy-balance terms. The models were run assuming
laser heating at 532 nm at fluences of 0.05 and 0.70 J/cm2
with a laser temporal profile provided. Calculations were performed
for a single primary particle with a diameter of 30 nm at
an ambient temperature of 1800 K and a pressure of 1 bar. Preliminary
calculations were performed with a fully constrained
model. The comparison of unconstrained models demonstrates
a wide spread in calculated LII signals. Many of the differences
can be attributed to the values of a few important parameters,
such as the refractive-index function E(m) and thermal and
mass accommodation coefficients. Constraining these parameters
brings most of the models into much better agreement
with each other, particularly for the low-fluence case. Agreement
among models is not as good for the high-fluence case,
even when selected parameters are constrained. The reason for
greater variability in model results at high fluence appears to
be related to solution approaches to mass and heat loss by
sublimation.