Simplified Model for Soot Formation and Oxidation in CFD Simulation of Non-Premixed Hydrocarbon Flames.
Simplified Model for Soot Formation and Oxidation in CFD
Simulation of Non-Premixed Hydrocarbon Flames.
(1967 K)
Lautenberger, C. W.; deRis, J. L.; Dembsey, N. A.;
Barnett, J. R.; Baum, H. R.
Fire Safety Journal, Vol. 40, No. 2, 141-176, March
2005.
Keywords:
hydrocarbon flames; soot formation; oxidation;
computational fluid dynamics; simulation; soot; smoke;
combustion; diffusion flames; fire dynamics; flame
radiation; equations; smoke points; hydrocarbon fuels;
flame height
Abstract:
A new approach to modeling soot formation and oxidation
in non-premixed hydrocarbon flames has been developed
and subjected to an initial calibration. The model
considers only the phenomena essential for obtaining
sufficiently accurate predictions of soot concentrations
to make CFD calculations of fire radiation feasible in
an engineering context. It is generalized to multiple
fuels by relating the peak soot formation rate to a
fuel's laminar smoke point height, an empirical measure
of relative sooting propensity, and applying simple
scaling relationships to account for differences in fuel
stoichiometry. Soot oxidation is modeled as a surface
area independent process because it is controlled by the
diffusion of molecular oxygen into the zone of active
soot oxidation rather than being limited by reaction of
OHDT radicals with the available soot surface area. The
soot model is embedded within a modified version of
NIST's Fire Dynamics Simulator and used for a comparison
of predicted and measured temperatures, soot volume
fractions, and velocities in laminar ethylene,
propylene, and propane flames. The basic approach,
though promising, is not yet mature and several
suggestions for future work are presented.
