1. RESEARCH POSTER PRESENTATION DESIGN © 2012
www.PosterPresentations.com
Our goal for this project is to realistically simulate fire suppression by water using FDS,
and then compare the result obtained with the ones from Openfoam. Firstly, we
simulated a fire being suppressed by water through sprinklers; however, the complexity
of the problem and the fact that fire suppression by water has not been validated
experimentally led us to build simpler models. Therefore, our first assumptions were,
the problem is either on the combustion model or on the droplets evaporation model. We
decided to start by studying the evaporation model With that in mind, we created a
simpler model, which consist of droplets being injected by a nozzle in to a warm
environment, where consequently evaporate.
Abstract
Results
Conclusions
As a summary, droplet size matters to the cooling of the domain. It can be explained by
longer penetration of the jet into the room, by the fact that smaller droplets require
lesser energy to evaporate and the fact that smaller penetration of the jet results in the
steam exiting the room without cooling a big part of it. The exit temperature does not
change much with the droplet diameter. On the other hand, FDS simulations with smaller
droplets lead to unexpected results like local temperature increase. Very high room
temperature also lead to unexpected results like overall temperature increase, which
might be explained by the fact that with higher temperatures there is a lot of energy
transfer to be calculated and thus, higher numercial error.
Objectives
Validate FDS droplet transport and evaporation model.
• Study the droplet evaporation in a closed and open heated environment.
• Study the influence of droplet size on the jet cooling power.
Validate FDS fast chemistry combustion model for water suppression.
Future work
To actually validate the FDS droplet transport and evaporation model some practical
experiments should be made. The flow out of the sprinkler/nozzle should be analyzed in
order to input the best sprinkler/nozzle characteristics into FDS; some attention should
be given to the droplet size distribution so that it can be adjusted to reality. A practical
experiment of a jet of droplets being ejected to a warm environment should be
assembled to compare it’s penetration with the one obtained in FDS. Similar models
should be created with FDS and Openfoam in order to compare the results obtained in
both software. Finally, after we are sure that the droplet model is accurate, the actually
flame suppression should be studied to understand if FDS correctly simulates that
phenomenon.
• Temperature Slice: Flow Configuration: 700 Microns (Left), 500 Microns (Middle), 350
Microns (Right)
João Melo
André Farinha
Characterization of droplet transport and evaporation model in the
CFD Software Fire Dynamics Simulator (FDS)
• Droplet’s Flow configuration: Flow Configuration: 700 Microns (Left), 500 Microns
(Middle), 350 Microns (Right)
• Jet in to a closed environment Temperature
Results
• Flame Temperature Distribution during sprinkler suppression