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Modeling fire scenarios in buildings with CFD

  • In the frame of the European harmonization, new European technical standards (Eurocodes) have been developed in recent years. Classical methods, like tables and simplified analytical procedures, as well as general engineering techniques are allowed by the Eurocodes for the fire protection design. The modeling and calculation of fire scenarios with CFD (Computational Fluid Dynamics) numerical methods is one of the general engineering methods. It is nowadays still difficult to check and evaluate the CFD results for their use as technical documents for fire safety design. Analytical engineering techniques, zone models and CFD-models have been used and compared in the present work for the prediction of the fire development in a building. To solve the conservation equation for the CFD-model, the CFD-program FDS, with the mixture fraction model, and the CFD-program FLUENT, with the one step reaction model as well as with the volumetric source term model, have been used. The combustion ofIn the frame of the European harmonization, new European technical standards (Eurocodes) have been developed in recent years. Classical methods, like tables and simplified analytical procedures, as well as general engineering techniques are allowed by the Eurocodes for the fire protection design. The modeling and calculation of fire scenarios with CFD (Computational Fluid Dynamics) numerical methods is one of the general engineering methods. It is nowadays still difficult to check and evaluate the CFD results for their use as technical documents for fire safety design. Analytical engineering techniques, zone models and CFD-models have been used and compared in the present work for the prediction of the fire development in a building. To solve the conservation equation for the CFD-model, the CFD-program FDS, with the mixture fraction model, and the CFD-program FLUENT, with the one step reaction model as well as with the volumetric source term model, have been used. The combustion of polyurethane is modeled in FDS by specifying the heat release rate and the stoichiometry. For the combustion in volumetric source term model, the heat release rate and the smoke release were specified with respect to the stoichiometry. The input parameter for the one step reaction model is the pyrolysis mass flow. In the one step reaction model, the transport equations for polyurethane, H2O, N2, O2, CO2, CO and C (soot) are solved and the heat of combustion is determined from the standard formation enthalpy of all the components. In volumetric source term model, the transport equation is solved for air and smoke. FDS solves the transport equation for the mixture fraction. To model the fire development, and where no literature data was available, the required material characteristics like specific heat capacity, absorption coefficient and heat of combustion were measured. In all the investigated CFD-models the heat- and species transport equation has been solved and the absorption coefficient of soot has been considered. Furthermore, the fire development has also been investigated using zone models with the programs CFAST and MRFC. Results from analytical engineering techniques (plume calculations), which were design criteria in the past, have been used as plausibility checks for the present work. The calculation results from the investigations were compared to measurements in the same building performed by the National Institute for Standards and Technology (NIST).zeige mehrzeige weniger

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Metadaten
Autoren/innen:Christian Knaust, Ulrich Krause, Anja Hofmann-Böllinghaus, U. Schneider
Dokumenttyp:Beitrag zu einem Sammelband
Veröffentlichungsform:Graue Literatur
Sprache:Englisch
Titel des übergeordneten Werkes (Englisch):11th International symposium on fire protection
Jahr der Erstveröffentlichung:2010
Herausgeber (Institution):German Fire Protection Association
Erste Seite:1
Letzte Seite:14
Freie Schlagwörter:Analytical technique; CFAST; CFD; Combustion; Computational fluid dynamics; FDS; FLUENT; MRFC; Measurements; Soot model; Zone model
Veranstaltung:11th International symposium on fire protection
Veranstaltungsort:Leipzig, Germany
Beginndatum der Veranstaltung:2010-06-08
Enddatum der Veranstaltung:2010-06-09
Verfügbarkeit des Dokuments:Physisches Exemplar in der Bibliothek der BAM vorhanden ("Hardcopy Access")
Bibliotheksstandort:Sonderstandort: Publica-Schrank
Datum der Freischaltung:19.02.2016
Referierte Publikation:Nein