Ay. Snegirev et al., The effect of particle coagulation and fractal structure on the optical properties and detection of smoke, FIRE SAFE J, 36(1), 2001, pp. 73-95
Numerical simulation and analysis of the effect of coagulation on the optic
al properties of smoke and its detectability are given for a burner fire in
a multi-room environment. The specific extinction coefficients are calcula
ted for smoke composed of polydisperse spherical particles and soot fractal
-like aggregates. Qualitatively different dependencies of specific extincti
on on mean-volume diameter and, due to coagulation, smoke residence time ar
e illustrated for these kinds of smoke by 2-D and 3-D simulations of fire-d
riven smoke flow. The light-scattering and ionisation detector response and
time needed to trigger an alarm are compared in terms of the coagulation e
ffect. Calculations without consideration of coagulation underestimate the
response of the light-scattering detector and overestimate the response of
the ionisation detector. The inclusion of coagulation and the fractal-aggre
gate description reduces the sensitivity of modelling results to uncertaint
y in input data concerning the size of the smoke aerosol particles inside t
he flame zone. (C) 2001 Elsevier Science Ltd. All rights reserved.