TY - CONF A1 - Wehrstedt, Klaus-Dieter A1 - Blankenhagel, Paul T1 - Organic peroxide fireballs - Project summary (2016 - 2018) N2 - Final report of research activities at BAM concerning large scale fireballs of organic peroxides (OP). New models for OP fireball diameter, duration, height and Surface Emmissive Power (SEP) are proposed and discussed based on a large number of large-scale and small-scale experiments using Di-tert-butylperoxide (DTBP) as a liquid OP and heptane as a liquid hydrocarbon fuel. Finally, CFD simulations are used to predict the fireball parameters: diameter, duration, height and SEP. Also the impact on the German storage regulations for organic peroxides are discussed. T2 - IGUS EOS Meeting 2019 CY - Brussels, Belgium DA - 21.04.2019 KW - Fireball KW - Organic Peroxide KW - DTBP KW - Thermal Radiation KW - CFD KW - Safety distances PY - 2019 AN - OPUS4-48522 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wehrstedt, Klaus-Dieter A1 - Schmidt, Simon A1 - Mishra, Kirti Bhushan T1 - CFD based reproduction of Amuay refinery accident 2012 N2 - Amuay accident 2012 is one of similar accidents happened in Buncefield (2005), Jaipur and Puerto Rico (2009), respectively. Since experimental reproduction of such accidents is not always possible numerical simulations help a lot to understand the scenarios on qualitative basis. In this work the accident is reproduced with a CFD model which takes into account the heaviness of the gas (LPG), wind and gravity driven spread. The leak was reported to be located near a number of spherical tanks. The ignition source was presumably the running vehicles on a nearby street. A part of the refinery containing the locations of leakage and ignition was considered as computational domain. The road is located at the eastern boarder. The area contains different tanks, whose height was estimated due to a lack of available data. The diameter was extrapolated from the available image data. Further, a grid of walls is located between a number of tanks. The total domain has a size of 750 m x 400 m x 50 m. An unstructured mesh was created using tetrahedral elements with prism layers at the ground to improve mesh quality in the boundary layer. The mesh has a total number of 775 686 cells. T2 - 15th Internation Symposium in Loss Prevention and Safety Promotion in the Process Industries CY - Freiburg, Germany DA - 05.06.2016 KW - CFD PY - 2016 AN - OPUS4-37195 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Schönbucher, A. A1 - Schälike, Stefan A1 - Vela-Wallenschus, Iris A1 - Wehrstedt, Klaus-Dieter ED - Schmidt, J. T1 - CFD simulation of large hydrocarbon and peroxide pool fires KW - Pool fire KW - JP 4 KW - Organic peroxide KW - DTBP KW - CFD KW - Surface emissive power KW - Irradiation KW - Safety distances PY - 2012 SN - 978-3-527-33027-0 N1 - Geburtsname von Vela-Wallenschus, Iris: Vela, I. - Birth name of Vela-Wallenschus, Iris: Vela, I. IS - Chapter 9 SP - 139 EP - 157 PB - Wiley-VCH Verlag GmbH & Co. KGaA AN - OPUS4-25897 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schälike, Stefan A1 - Wehrstedt, Klaus-Dieter A1 - Schönbucher, A. T1 - CFD simulation to predict the thermal radiation of large LNG pool fires N2 - Flame temperature (T), surface emissive power (SEP) of Liquefied Natural Gas (LNG) pool fires (d = 1 m, 6.1 m, 30 m) are investigated by CFD (Computational Fluid Dynamics) simulation and compared with experimental results. Time averaged flame temperatures of T = 1320 K, T = 1298 K and T = 1281 K are obtained. Surface emissive power (SEP) of 55 kW=m2, 130 kW=m2 and 230 kW=m2 are predicted. T2 - 5th European combustion meeting 2011 CY - Cardiff, UK DA - 28.06.2011 KW - Pool fire KW - LNG KW - CFD KW - Thermal radiation KW - Surface emissive power PY - 2011 SP - 1 EP - 6 AN - OPUS4-24687 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schälike, Stefan A1 - Vela-Wallenschus, Iris A1 - Wehrstedt, Klaus-Dieter A1 - Schönbucher, A. T1 - Vorhersage der thermischen Strahlung von KW-Poolfeuern mit CFD-Simulation T2 - Workshop Brandschutzforschung CY - Magdeburg, Deutschland DA - 2010-10-04 KW - Pool fire KW - Organic peroxides KW - TBPB KW - TBPEH KW - CFD KW - Safety distances PY - 2011 UR - http://www.vfdb.de/download/MagdeburgWorkshop2010/Schaelike_vfdb2010.pdf N1 - Geburtsname von Vela-Wallenschus, Iris: Vela, I. - Birth name of Vela-Wallenschus, Iris: Vela, I. SP - 1 EP - 25 AN - OPUS4-23352 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mishra, Kirti Bhushan A1 - Wehrstedt, Klaus-Dieter A1 - Schönbucher, A. T1 - Interpretations of temperature measurements in organic peroxide pool fires N2 - Most of the measurements of temperatures in large pool fires are indirect and present a number of complexities due to the interactions of convection, radiation and soot blockage. In the present work these influences for two organic peroxide [tert-butyl peroxybenzoate (TBPB) and tert-butyl peroxy-2-ethylhexanoate (TBPEH)] pool fires are analysed. Thermocouple measured temperature in the clear flame zone i.e. combustion zone are found to be 250-400 K lower than from the thermographic measurements. The convective and radiative heat flux contributions from the fire on temperature measurements are discussed. CFD (Computational Fluid Dynamics) simulations have been performed for large pool fires and the predicted time averaged flame temperatures were found to be in qualitative agreement with measurements due to the stoichiometric combustion model used in the present simulations. T2 - 5th European combustion meeting 2011 CY - Cardiff, UK DA - 28.06.2011 KW - Pool fire KW - Organic peroxides KW - TBPB KW - TBPEH KW - CFD KW - Temperature measurement PY - 2011 UR - http://www.uni-due.de/tchem/as/skripte/paper_mishra_et_al_cardiff_2011.pdf SP - 1 EP - 5 AN - OPUS4-24686 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mishra, Kirti Bhushan A1 - Wehrstedt, Klaus-Dieter A1 - Schönbucher, A. T1 - Radiative characteristics of large pool fires of organic peroxides T2 - 4th European Combustion Meeting (Proceedings) CY - Vienna, Austria DA - 2009-04-14 KW - Pool fire KW - TBPB KW - TBPEH KW - CFD KW - Temperature KW - Surface emissive power KW - Irradiance PY - 2009 SN - 978-3-902655-06-6 SP - 1 EP - 6(?) PB - ProcessEng Engineering GmbH CY - Vienna AN - OPUS4-19400 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mishra, Kirti Bhushan A1 - Wehrstedt, Klaus-Dieter A1 - Schönbucher, A. T1 - Safety aspects of organic peroxide pool fires T2 - COMBURA 2010 - Combustion research and application CY - Maastricht, The Netherlands DA - 2010-10-12 KW - Pool fire KW - Organic peroxides KW - TBPB KW - TBPEH KW - CFD KW - Safety distances PY - 2010 SP - 11 EP - 12 AN - OPUS4-22484 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mishra, Kirti Bhushan A1 - Wehrstedt, Klaus-Dieter T1 - CFD simulation of hybrid fuel combustion T2 - NCFMFP 2012 - 39th National conference on fluid mechanics and fluid power CY - Surat, Gujarat, India DA - 2012-12-13 KW - CFD KW - Hybrid fuel KW - Hydrocarbon KW - Peroxy-fuel KW - Combustion PY - 2012 SN - 978-81-925-494-0-8 IS - FMFP2012 - 209 SP - 1 EP - 7(?) AN - OPUS4-27587 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mishra, Kirti Bhushan A1 - Wehrstedt, Klaus-Dieter T1 - Spill-over characteristics of peroxy-fuels: Two-phase CFD investigations N2 - Two-phase CFD (Computational Fluid Dynamics) model for characterising the spill-over/dispersion of peroxy-fuels is presented. The model is independent of type and burning rate of the spilled/dispersed fuel and considers only overflow Reynolds number (Re) to characterise the spill/dispersion behaviour. Additional simulations are performed for LNG (Liquified Natural Gas) dispersion and it is found that the model can be used for different fuels within a defined range of Re. Different scenarios with Re = 100 to 3 × 105 are investigated covering a wide range of mass flow rates, opening sizes and viscosities. Depending on Lower Flammability Limits (LFL) of the fuels spill/dispersion (vapour cloud) diameters (DCFD) and heights (hCFD) are predicted. A generalised correlation between DCFD and Re is established to predict the dispersion occurring at varying scales. The model is validated by: (1) conducting an extensive grid independent study; (2) comparing the results with the existing analytical methods and (3) comparing against the standard field test data on LNG dispersions. KW - Spill-over KW - Dispersion KW - Peroxy-fuels KW - CFD KW - Reynolds number KW - Liquefied natural gas PY - 2014 DO - https://doi.org/10.1016/j.jlp.2014.02.014 SN - 0950-4230 SN - 1873-3352 VL - 29 SP - 186 EP - 197 PB - Butterworth CY - Guildford, Surrey AN - OPUS4-30481 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mishra, Kirti Bhushan A1 - Wehrstedt, Klaus-Dieter T1 - Rheinland refinery accident 2014: CFD prediction of atmospheric dispersion of smoke N2 - Industrial fire and explosion hazards are most often also associated with the dispersion of toxic substances. These substances can be gases, liquids, solids or in form of aerosols. The critical toxic exposure limits to People and enviroment from such substances are regulated by the concerned authorities of the countries. In order to comply with the defined regulation estimation of such critical limits must be carried out by different semi-empirical and phenomenological models/methods for risk assessment. Many of such methods provide a qualitative estimation of time and space dependent extrimities of toxicity. The overwhelm development of computational capacity has made it possible to perform Computational Fluid Dynamics (CFD) simulation by solving the three-dimensional transport equations for mass momentum and species in lower and upper atmosphere, respectively. CFD simulation not only provides a detailed 3D distribution of toxic particulates/gases in the neighbourhood of the plant but also helps to study the worst-case sceanrios. In the past several small- and large-scale accidents occured in oil and gas plants in different parts of the world including the recent one in Rheinland refinery near Cologne in Germany. This work deals with this accident and provides a methodology to predict the critical exposure limits of smoke emitted by a toluene tank fire by means of CFD simulation. T2 - COMBURA 2014 - Combustion research and application symposium CY - Soesterberg, The Netherlands DA - 08.10.2014 KW - CFD KW - Retinery incident KW - Smoke dispersion PY - 2014 SP - 56 EP - 57 AN - OPUS4-31721 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mishra, Kirti Bhushan A1 - Wehrstedt, Klaus-Dieter T1 - Underground gas pipeline explosion and fire: CFD based assessment of foreseeability N2 - Scenarios of underground gas pipeline failure, crater formation, dispersion of gas, explosion and subsequent fires are investigated with semi-empirical and with CFD (Computational Fluid Dynamics) modelling. In order to strengthen the accident based learning approaches present investigations are performed in the context of recent GAIL (Gas Authority of India Limited) natural gas pipeline incident occurred in India. The foreseeability of damages to lives of people and assets due to explosion overpressure and thermal radiation are assessed. The released gas is considered as slightly dense-than-air i.e. 1.5 times. Depending on the LFL (Lower Flammability Limit) of gas the dispersion diameter and heights are predicted which followed the visual evidences appropriately. The model was furthermore tested with an even denser medium and was found to be worked well there too. The estimated explosion overpressures with the standard methods and also with CFD reproduced the scenario nicely. The effects of congestion VBR (Volume Blockage Ratio) in form of vegetation on stable atmospheric boundary layer flow is analysed and its contribution towards turbulence and hazard enhancement is studied. It is found that the major source of fatalities was higher thermal radiation emitted by pool fires of methane. The estimated thermal safety distances clearly demonstrate the ignorance/under estimation of likelihood and consequence of such hazardous events. For such incidents CFD demonstrated a strong capability to assess the pre or/and post events foreseeabilities within a reasonable amount of time and with an acceptable level of accuracy meeting the industrial needs for risk analysis. KW - Natural gas KW - Underground pipeline KW - Dense gas dispersion KW - Explosion and fire KW - CFD KW - Safety distance PY - 2015 DO - https://doi.org/10.1016/j.jngse.2015.04.010 SN - 1875-5100 VL - 24 SP - 526 EP - 542 PB - Elsevier CY - Amsterdam [u.a.] AN - OPUS4-33671 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Knechtel, Sophie A1 - Schmidt, Simon A1 - Mishra, K. B. A1 - Wehrstedt, Klaus-Dieter T1 - Modellierung der Hauptbrandszenarien von flüssigem Wasserstoff (LH2) mittels CFD N2 - Die sichere Lagerung und der Transport von Flüssigwasserstoff (LH2) verlangen nach verlässlichen Abschätzungen möglicher Risiken durch Feuer oder Explosion. Aufgrund des breiten Explosionsbereichs (4 Vol.-% - 74 Vol.-%) reagiert Wasserstoff sehr schnell und produziert hohe Flammentemperaturen. Da Wasserstoffflammen ruß- bzw. farblos sind, ist Wärmestrahlung im Fernfeld kein Risikofaktor. Allerdings stellen die hohe lokale Wärmestrahlung und die nicht sichtbaren Flammen eine Gefahr für Menschen und Infrastruktur in der Nähe dar. Es ist daher notwendig die Gefahren von LH2-Feuern sorgfältig zu bewerten. Einerseits sind experimentelle Untersuchungen verschiedener Szenarien teuer, andererseits können sie teilweise auch praktisch nicht durchführbar sein. Numerische Simulationen dieser Szenarien können ein Ausweg aus diesem Problem sein. In der vorliegenden Arbeit wird ein solcher Ansatz genutzt, um große Brandszenarien mit LH2 mittels CFD (Computational Fluid Dynamics) zu modellieren und so die notwendigen Sicherheitsabstände abzuschätzen. Der Fokus liegt dabei auf der Simulation von Jet- und Pool-Feuerszenarien mit einem kommerziellen CFD-Code (Ansys CFX). Die benötigten geometrischen Modelle werden für Jet- und Pool-Feuer erstellt und mit den nötigen Randbedingungen implementiert. Wichtige Submodelle für chemische Reaktionen (Einschritt- und detaillierte Modelle), Verbrennung (Eddy-Dissipation- und Flamelet-Modell) und Strahlung (Discrete-Transfer-Modell) werden genutzt. Die maximal simulierten Flammentemperaturen liegen bei ~2100 K für Jet-Feuer und ~2300 K für Pool-Feuer. Um Aussagen zu thermischen Sicherheitsabständen zu treffen, wurden die Spezifischen Ausstrahlungen (SEP) ermittelt und anschließend entsprechende Positionsfaktoren gewählt, um verlässliche Sicherheitsabstände zu berechnen. Je nach Bedarf können CFD-Modelle sowohl für qualitative als auch für quantitative Risikobewertungen von LH2-Großbränden genutzt werden. T2 - 12. Fachtagung Anlagen-, Arbeits- und Umweltsicherheit CY - Köthen, Germany DA - 05.11.2015 KW - Flüssigwasserstoff KW - Großbrand KW - Poolfeuer KW - Jet-Feuer KW - CFD KW - Sicherheitsabstand PY - 2015 SN - 978-3-86011-091-1 SP - Paper P-11, 1 EP - 8 AN - OPUS4-34827 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -