NIST Time|NIST Home|About NIST|Contact NIST

HomeAll Years:AuthorKeywordTitle2005-2010:AuthorKeywordTitle

Coagulation of Aerosols With Broad Initial Size Distributions.

pdf icon Coagulation of Aerosols With Broad Initial Size Distributions. (14397 K)
Mulholland, G. W.; Lee, T. G.; Baum, H. R.

U.S./Japan Government Cooperative Program on Natural Resources (UJNR). Panel on Fire Research and Safety. Volume 6. Fire Detection. October 19-22, 1976, Tokyo, Japan, 1-49 pp, 1976.

Journal of Colloid and Interface Science, Vol. 62, No. 3, 406-420, 1977.


fire detection; fire research; fire safety; size distributions; aerosols; coagulation; particle size; smoke; smoldering


The effect of coagulation on an aerosol with a broad initial size distribution was calculated analytically for large and small particle sizes for arbitrary time with the assumption of a constant coagulation collision frequency. It was found for the class of algebraic initial distributions that in general there is no self-preserving size distribution though for the special case of a Junge like algebraic size distribution there is a quasi self-preserving form. The calculation also demonstrates that coagulation alone leads to dynamic equilibrium for large particle size without the need of additional physical processes such as particle sedimentation. The relevance of the calculations to real aerosols was tested by measuring the size distribution of smoke generated from smoldering "punk" and flaming alpha-cellulose. The size distributions of both smoke aerosols are not only self-preserving but also are very similar. there is quantitative agreement between the measured size distributions and the calculated quasi self-preserving form.