CBET Award Achievements
Notable Accomplishments from CBET Awards
 

Fire Protection through Modeling and Simulation

Paul DesJardin    University at Buffalo, the State University of New York


Background:  The financial loss to developing nations due to fires is enormous accounting for upwards of 1% of the gross domestic product that easily translates into billions of dollars per year.  It is surprising then that while the existence of fire has been around since the beginning of man, the underlying science of fires has only started to be fully understood.  The basic challenge in controlling these fires is predicting the performance of suppression delivery systems that depends on the understanding of dynamics of flame suppression processes in highly turbulent, strongly radiating, multiphase, combusting flows requiring the knowledge of several material phase states.  The combination of these various processes is a multidisciplinary problem requiring the detailed knowledge of both fluid and solid mechanics.  In recent times with the advent of faster computers and advanced diagnostic tools, this research is starting to unravel the mysteries of this very complex dynamical system that will eventually lead to better engineering practices to protect buildings and other structures from a fire.

The Approach and Results:  The technical approach of our research is to develop advanced modeling and simulation tools for predicting the suppression of large scale fires using water mists and sprays that are commonly used to protect buildings.  Two fundamental challenges have to be overcome for these tools to become reality.  The first is modeling the local turbulent mixing environment.  Our approach is to pursue stochastic processes descriptions for this purpose and have recently pushed the frontier of knowledge in this area by developing the mathematical framework and numerical algorithms for describing turbulent-chemistry interactions for multiphase flows.  The second challenge is predicting the thermal radiation heat transfer.  Radiation is emitted from the formation of soot in the fire and accounts for nearly 60% of the overall energy content in the fuel.  In water spray environments, the thermal radiation is locally attenuated by its absorption into the water droplets is highly wavelength dependent.  A complete description of the thermal radiation field therefore would require, in general, solution of the equation governing radiation each transfer for each wavelength requiring the solution of an enormous number of simultaneous partial differential equations.  This is not feasible even with the largest of super computers.  We are therefore exploring means to efficiently solve the entire thermal radiation field without sacrificing accuracy.  The approach is based on re-ordering the wavelength dependent properties in terms of a frequency distribution.  These developments have lead to unique large scale simulation capability for examining large hydrocarbon pool fires.  Representative results are illustrated in the Figure below and show a snapshot of the soot produced in the fire and the associated radiation heat flux the surrounding enclosure walls.


Paul DesJardin Image
 
Snapshot of a large hydrocarbon pool fire showing an isosurface of soot volume fraction with temperature contours superimposed.  Contours on the walls of the room show the radiation heat flux emitting from the hot soot in the fire.

Credit:  Paul DesJardin University at Buffalo, the State University of New York


This work is notable because, for the first time, turbulence-chemistry-radiation interactions for a multiphase flow are treated in a self-consistent probabilistic format.  It has the potential of a large impact in other applications that include internal combustion engines and gas-turbines.

This work involves multidisciplinary research.  The work requires the knowledge of turbulent multiphase flows, chemistry, radiation heat transfer, solid mechanics and high-performance computing.  Furthermore, mathematical concepts related to stochastic process descriptions are essential for the development of the modeling.


     
Program Officer:   Phillip Westmoreland
     
NSF Award Number:   0348110
     
Award Title:   CAREER: High Fidelity Numerical Modeling and Simulation of Fire Suppression
     
PI Names:   Paul E. DesJardin
     
Institution Name:   University at Buffalo, the State University of New York
     
Program Element:   1407
     
CBET Nugget:   FY 2006
     

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This Nugget was Updated on 25 September 2008.