TY - CONF A1 - Knaust, Christian A1 - Krause, Ulrich A1 - Hofmann-Böllinghaus, Anja A1 - Schneider, U. T1 - Modeling fire scenarios in buildings with CFD T2 - Proceedings of the 11th international symposium on fire protection N2 - 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 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). T2 - 11th International Symposium on Fire Protection CY - Leipzig, Germany DA - 08.06.2010 KW - CFD KW - Computational fluid dynamics KW - Zone model KW - Analytical technique KW - Combustion KW - Soot model KW - FLUENT KW - FDS KW - CFAST KW - MRFC KW - Measurements PY - 2010 SN - 978-3-00-03966-2 N1 - Geburtsname von Hofmann-Böllinghaus, Anja: Hofmann, A. - Birth name of Hofmann-Böllinghaus, Anja: Hofmann, A. SP - 1 EP - 14 PB - Vereinigung zur Förderung des Deutschen Brandschutzes (vfdb) CY - Münster AN - OPUS4-23159 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Knaust, Christian A1 - Festag, S. A1 - Brüne, M. A1 - Dietrich, Matthes A1 - Amecke-Mönninghoff, Stephan A1 - Konrath, B. A1 - Arnold, L. T1 - Modellierung eines Brandes in einer U-Bahn-Station: Validierung von Rechenmodellen auf der Grundlage von Feldversuchen T2 - Magdeburger Brand- und Explosionsschutztage 2017 N2 - Mittels Propan-Brennern mit einer Brennerleistung 750 kW wurden in einer U-Bahn-Station Heißgasversuche durchgeführt und die zeitlichen und örtlichen Verteilungen der physikalischen Größen (Stoffkonzentration, Temperatur und Rauchgasdichte) erfasst. Laborversuche sowie die Feldversuche sind Validierungsgrundlage für ANSYS CFX und FDS und die später im Rechenmodell der U-Bahn-Station zur Untersuchung der Grundströmung und Rauchausbreitung verwendeten mathematisch-physikalischen Modelle. Der Aufsatz stellt das Projekt ORPHEUS vor und diskutiert die ersten Ergebnisse. T2 - Magdeburger Brand- und Explosionsschutztage 2017 CY - Magdeburg, Germany DA - 23.03.2017 KW - Rechenmodelle KW - Ansys CFX KW - FDS KW - Computational fluid dynamics KW - CFD KW - Rauchausbreitung KW - Validierung KW - U-Bahn KW - Brandszenarien KW - Modellierung von Bränden PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-396694 SN - 978-3-00-056201-3 DO - https://doi.org/10.978.300/0562013 SP - 1 EP - 12 PB - Otto-von-Guericke-Universität Magdeburg CY - Magdeburg AN - OPUS4-39669 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Knaust, Christian A1 - Rogge, Andreas ED - Lönnermark, A. ED - Ingason, H. T1 - Prediction of the temperature evolution in a tunnel construction in case of fire, by coupling the temperature-dependent heat transfer mechanisms inside the structural components and at their surface T2 - 5th International Symposium on tunnel safety and security (Proceedings) T2 - 5th International Symposium on tunnel safety and security CY - New York, USA DA - 2012-03-14 KW - Fire KW - High tmeperature fire loads KW - Component temperatures KW - Wall temperatures KW - Concrete KW - High temperature behavior KW - Thermal properties KW - Computational Fluid Dynamics KW - CFD PY - 2012 SN - 978-91-87017-26-1 SN - 0284-5172 VL - 2 SP - 753 EP - 756 AN - OPUS4-28067 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Berchtold, Florian A1 - Knaust, Christian A1 - Rogge, Andreas A1 - Arnold, L. A1 - Thöns, Sebastian ED - Lönnermark, Anders ED - Ingason, Haukur T1 - Risk Analysis for Road Tunnels – A Metamodel to Efficiently Integrate Complex Fire Scenarios T2 - Proceedings from the Eighth International Symposium on Tunnel Safety and Security N2 - Fires in road tunnels constitute complex scenarios with interactions between the fire, tunnel users and safety measures. More and more methodologies for risk analysis quantify the consequences of these scenarios with complex models. Examples for complex models are the computational fluid dynamics model Fire Dynamics Simulator (FDS) and the microscopic evacuation model FDS+Evac. However, the high computational effort of complex models often limits the number of scenarios in practice. To balance this drawback, the scenarios are often simplified. Accordingly, there is a challenge to consider complex scenarios in risk analysis. To face this challenge, we improved the metamodel used in the methodology for risk analysis presented on ISTSS 2016. In general, a metamodel quickly interpolates the consequences of few scenarios simulated with the complex models to a large number of arbitrary scenarios used in risk analysis. Now, our metamodel consists of the projection array-based design, the moving least squares method, and the prediction interval to quantify the metamodel uncertainty. Additionally, we adapted the projection array-based design in two ways: the focus of the sequential refinement on regions with high metamodel uncertainties; and the combination of two experimental designs for FDS and FDS+Evac. To scrutinise the metamodel, we analysed the effects of three sequential refinement steps on the metamodel itself and on the results of risk analysis. We observed convergence in both after the second step (ten scenarios in FDS, 192 scenarios in FDS+Evac). In comparison to ISTSS 2016, we then ran 20 scenarios in FDS and 800 scenarios in FDS+Evac. Thus, we reduced the number of scenarios remarkably with the improved metamodel. In conclusion, we can now efficiently integrate complex scenarios in risk analysis. We further emphasise that the metamodel is broadly applicable on various experimental or modelling issues in fire safety engineering. T2 - International Symposium on Tunnel Safety and Security CY - Boras, Sweden DA - 14.03.2018 KW - Risk KW - Metamodel KW - CFD KW - Evacuation KW - Uncertainty PY - 2018 SN - 978-91-88695-48-2 VL - 8 SP - 349 EP - 360 AN - OPUS4-44535 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -