Dokument-ID Dokumenttyp Autoren/innen Persönliche Herausgeber/innen Haupttitel Abstract Auflage Verlagsort Verlag Herausgeber (Institution) Erscheinungsjahr Titel des übergeordneten Werkes Jahrgang/Band ISBN Veranstaltung Veranstaltungsort Beginndatum der Veranstaltung Enddatum der Veranstaltung Ausgabe/Heft Erste Seite Letzte Seite URN DOI Lizenz Datum der Freischaltung OPUS4-28067 Beitrag zu einem Tagungsband Knaust, Christian; Rogge, Andreas Lönnermark, A.; Ingason, H. 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 SP Technical research institute of Sweden 2012 5th International Symposium on tunnel safety and security (Proceedings) 2 978-91-87017-26-1 5th International Symposium on tunnel safety and security New York, USA 2012-03-14 2012-03-16 753 756 2016-02-20 OPUS4-12207 Beitrag zu einem Sammelband Hofmann-Böllinghaus, Anja; Knaust, Christian; Beard, A. Modelling fire scenarios in residential buildings with respect to the benefit of smoke detectors and flame retardants London Interscience Communications 2006 Proceedings of the 12th International Flame Retardants 2006 Conference 0-9541216-7-8 12th International Flame Retardants 2006 Conference London, England, UK 2006-02-14 2006-02-15 195 214 2016-02-19 OPUS4-23159 Beitrag zu einem Tagungsband Knaust, Christian; Krause, Ulrich; Hofmann-Böllinghaus, Anja; Schneider, U. 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 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). Münster Vereinigung zur Förderung des Deutschen Brandschutzes (vfdb) 2010 Proceedings of the 11th international symposium on fire protection 978-3-00-03966-2 11th International Symposium on Fire Protection Leipzig, Germany 08.06.2010 09.06.2010 1 14 2016-02-19 OPUS4-44535 Beitrag zu einem Tagungsband Berchtold, Florian; Knaust, Christian; Rogge, Andreas; Arnold, L.; Thöns, Sebastian Lönnermark, Anders; Ingason, Haukur Risk Analysis for Road Tunnels - A Metamodel to Efficiently Integrate Complex Fire Scenarios 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. RISE Safety 2018 Proceedings from the Eighth International Symposium on Tunnel Safety and Security 8 978-91-88695-48-2 International Symposium on Tunnel Safety and Security Boras, Sweden 14.03.2018 16.03.2018 349 360 2018-03-21 OPUS4-50697 Zeitschriftenartikel Eberwein, Robert; Rogge, Andreas; Behrendt, F.; Knaust, Christian Dispersion Modeling of LNG-Vapor on Land - A CFD-Model Evaluation Study Based on methane from renewable resources, LNG is an alternative fuel for heavy and long-distance traffic in land transport. Contrary to its positive properties, the fuel contains risks from an explosion and extremely low temperatures for personal and infrastructure safety. CFD-models are suitable for doing risk analyses for arbitrary scenarios. For examining how to model for risk research the dispersion of LNG-vapor, this paper contains a model variant study, with an evaluation by experiments. This paper describes the use of the CFD-code ANSYS Fluent for simulating experiments of the 'LNG Safety Program Phase II'. The content of the well-documented experiments was the research of the vaporization rate of LNG on land and the dispersion of LNG-vapor in the air. Based on the comparison to two experiments, overall 12 CFD-model variants with varying thermal and turbulence parameters were examined how they affect the transient LNG-vapor dispersion in air. The definition of turbulence-boundary-condition at the domain borders had the biggest impact on modeling, followed by the turbulence model. The most accurate model variant had been applied for observing the spreading behavior of LNG-vapor in the air after evaporation on land and analyzing the influence of the LNG-composition to the dispersion. The results show that the mixture of LNG-vapor and the air in the free field is cooler than the ambient air and spreads like a heavy gas on the ground. Elsevier Ltd. 2020 Journal of Loss Prevention in the Process Industries 65 104116 10.1016/j.jlp.2020.104116 2020-04-27 OPUS4-39667 Forschungsbericht Knaust, Christian; Amecke-Mönninghoff, Stephan Entwicklung eines Verfahrens zur Brandlastberechnung unter Anwendung der Verbrennungseffektivität und unter Berücksichtigung des Temperatur-Zeit-Verlaufs im Bauteil Nach DIN 18230-1 erfolgt in Deutschland die Brandlastberechnungen unter Anwendung des Abbrandfaktors m. Der Abbrandfaktor m ist ein dimensionsloser Beiwert mit dem die Brandlast aus einem Stoff oder Stoffgemisch bewertet wird. Neben dem Brandverhalten des Stoffes berücksichtigt er das Temperatur-Zeit-Verhalten im Bauteil. Die einzige Prüfapparatur, mit der Abbrandfaktoren bestimmt wurden, ist jedoch nicht mehr existent. Ein Wiederaufbau der abgeschafften Prüfapparatur wurde wegen apparateabhängigen Messunsicherheiten und auch aus wirtschaftlichen Gründen als nicht sinnvoll angesehen. Die Erarbeitung eines äquivalenten Verfahrens zum Abbrandfaktor m unter Verwendung der Verbrennungseffektivität und unter Berücksichtigung der Bauteilerwärmung war daher Gegenstand dieses Forschungsvorhabens. Ziel war es für Brandlastberechnungen nach DIN 18230-1 die Verbrennungseffektivität anzuwenden. Die Verbrennungseffektivität beschreibet jedoch nur den verringerten Energieumsatz von Stoffen im Brandraum. Es wurde daher ein Verfahren erarbeitet, dass ergänzend zur Brandlastberechnung unter Anwendung der Verbrennungseffektivität das Temperatur-Zeit-Verhalten in einem brandbelastenden Bauteil berücksichtigt. Stuttgart Fraunhofer IRB Verlag 2017 F 3001 978-3-8167-9928-3 1 53 2017-04-05 OPUS4-39669 Beitrag zu einem Tagungsband Knaust, Christian; Festag, S.; Brüne, M.; Dietrich, Matthes; Amecke-Mönninghoff, Stephan; Konrath, B.; Arnold, L. Modellierung eines Brandes in einer U-Bahn-Station: Validierung von Rechenmodellen auf der Grundlage von Feldversuchen 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. Magdeburg Otto-von-Guericke-Universität Magdeburg 2017 Magdeburger Brand- und Explosionsschutztage 2017 978-3-00-056201-3 Magdeburger Brand- und Explosionsschutztage 2017 Magdeburg, Germany 23.03.2017 24.03.2017 1 12 urn:nbn:de:kobv:b43-396694 10.978.300/0562013 2017-04-26