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Dispersion from strongly buoyant sources

Objective

A simple mathematical model of a plume designed for conditions of a very high buoyancy, as are found in toxic plumes from fires.

A carefully designed set of experimental data for the high buoyancy, near field, region, covering appropriate ranges of the important source variables.

A PC-based computer program to solve the model equations in a way which is readily accessible to hazard analysts.

Validation of the model against this and other existing data.


Integral models which predict the downstream evolution of steady plumes have been developed, and applied successfully in hazard analysis, for a number of different physical situations. These include passive plumes, plumes from stacks, high momentum jets, and steady continuous releases of a heavy gas cloud.

The success of such models is based largely on their simplicity, which makes them readily available to the hazard analyst. Their derivation, however, relies heavily on insight gained from the experiment, and their accuracy and credibility rests very heavily on validation through comparison with good quality, comprehensive experimental data.

Stongly buoyant plumes, including fire plumes, have in the past received rather less attention than the other flows mentioned, both from the theoretical and experimental viewpoints.

All of the flow models discussed above share a number of common features with that proposed here, mainly in the overall framework for the description of the mlume.

However, the physics of dispersion involves quite different features in each case. This arises from the overall buoyancy of the flow and the very different turbulence properties which are strongly dependent on stratification, buoyancy, and momentum.

The innovative areas in understanding stronly buoyant fire plumes will include addressing questions relating to

the features of the flow development in the very near field;

the transverse radial structure of the plume;

consequences of the plume reaching an inversion layer;

the formation, transformation, and deposition of particulate matter formed in the fire.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

AEA TECHNOLOGY PLC
Address
329,Harwell 329
OX11 0QJ Didcot,harwell,chilton
United Kingdom

Participants (2)

FINNISH METEOROLOGICAL INSTITUTE
Finland
Address
20 E,sahaajankatu 20 E
00810 Helsinki
UNIVERSITY OF HAMBURG
Germany
Address
Bundesstrasse 55
20146 Hamburg