TY - JOUR A1 - Bernardy, Christopher A1 - Habib, Abdel Karim A1 - Kluge, Martin A1 - Orchini, A. ED - Fabiano, Bruno ED - Cozzani, Valerio T1 - Heat Radiation Emanating from Hydrogen and Methane Jet Fires N2 - Modelling the heat radiation emanating from jet flames for initial hazard assessment purposes is generally done using simple, steady-state, approaches that give a quick estimation useful for impact analysis. Although nowadays CFD can be used to simulate this phenomenon in detail, it is still very demanding in computational power and time, and generally not all required boundary conditions to achieve a reliable result are known. Therefore, even today simpler empirical approaches are still widely used for consequence analysis. Hydrogen is becoming increasingly important as renewable energy carrier resulting in an increasing demand of “hydrogen-approved” models. Since the aforenamed models were mainly developed based on data from hydrocarbon jet flame experiments, it has to be verified if they also apply to hydrogen jet flames. To this purpose, real-scale tests are carried out at the BAM Test Site Technical Safety (BAM-TTS) with the aim to assess the flame geometry and the emitted thermal radiation of hydrogen and methane jet flames. In particular, the focus is laid on the measurement and modelling of the thermal radiation. Existing heat radiation data from the literature are mostly based on unsteady outflow conditions. The experimental setup used here allows for the generation of a steady-state outflow and thus a direct comparability with existing (steady-state) models. From these data, an assessment of the applicability of jet flame models to hydrogen jet flames is carried out accounting for their accuracy in predicting heat radiation and possible needs of further development. T2 - 18th EFCE International Symposium on Loss Prevention and Safety Promotion in the Process Industries CY - Bologna, Italy DA - 08.06.2025 KW - Jet Fire KW - Hydrogen KW - Methane KW - Heat radiation PY - 2025 DO - https://doi.org/10.3303/CET25116065 SN - 2283-9216 VL - 116 SP - 385 EP - 390 PB - AIDIC Servizi S.r.l. CY - Italy AN - OPUS4-63698 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bernardy, Christopher A1 - Habib, Abdel Karim A1 - Kluge, Martin A1 - Schalau, Bernd A1 - Kant, Hanjo A1 - Schulze, Marcel A1 - Orchini, Alessandro T1 - Large-scale investigations of the thermal radiation of hydrogen jet flames N2 - For industrial applications dealing with hydrogen, the definition of safety distances and the assessment of possible hazards emanating from releases is mandatory. Since hydrogen is usually stored and transported under pressure, one scenario to be considered is the momentum driven release of hydrogen from a leakage with subsequent ignition. In this scenario, the emitted heat radiation from the resulting jet flame to the surroundings has to be determined to define adequate safety distances. For hydrocarbon flames, different jet flame models are available to assess the hazards resulting from an ignited jet release. Since hydrogen flames differ from hydrocarbon flames in their combustion behavior, it has to be checked if these models are also applicable for hydrogen. To evaluate the accuracy of these models for hydrogen jet flames, tests with a horizontal outlet at large-scale are carried out at the BAM Test Site for Technical Safety (BAM-TTS). Herein, the flame geometry and the heat radiation at defined locations in the surroundings are recorded for varying release parameters such as release pressure (currently up to max. 250 bar), mass flow (up to max. 0.175 kg/s) at an outlet diameter of 30 mm (with an upstream nozzle of 7.7 mm). The challenge here is the characterization of the flame geometry in an open environment and its impact on the thermal radiation. Existing heat radiation data from the literature are mostly based on unsteady outflow conditions. For a better comparability with the steady state jet flame models, the experiments presented here are focused on ensuring a constant mass flow over the release duration (currently 120 s) to obtain a stationary jet flame. In addition, stationary outflow tests with hydrocarbons (methane) were also carried out, which are intended to serve as reference tests for checking flame models based on hydrocarbon data. The comparison of the flame geometry shows that hydrogen jet flames with the same outlet mass flow have a greater flame length (average deviation of 15 %) but a smaller flame diameter than methane jet flames (average deviation of 17 %). Conclusions regarding thermal radiation show that the proportion of total combustion energy emitted as thermal radiation is lower for hydrogen (x_rad= 0.04–0.09) than for methane (x_rad = 0.06–0.1). A comparison of the surface emissive power (SEP) of the jet flame shows a SEP range of 7 kW/m2-15 kW/m2 for hydrogen and 3 kW/m2 - 9,5 kW/m2 for methane. KW - Hydrogen KW - Release KW - Thermal radiation KW - Jet flame KW - Radiant heat fraction PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-622891 DO - https://doi.org/10.1016/j.jlp.2024.105491 SN - 1873-3352 VL - 94 SP - 1 EP - 6 PB - Elsevier B.V. AN - OPUS4-62289 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bernardy, Christopher A1 - Habib, Abdel Karim A1 - Kluge, Martin A1 - Schalau, Bernd A1 - Kant, Hanjo A1 - Schulze, Marcel A1 - Orchini, Alessandro ED - Nabizada, A. ED - Dechany, A. ED - B. Carré, B. ED - Stendardo, E. ED - Lappa, F. ED - Vanlaere, J. ED - Mendoza, M.J. ED - Dejonghe, M. ED - Daese, M. ED - Namazifard, N. ED - Jacops, R. ED - Jottrand, S. ED - Pahlavan, S. T1 - Real scale safety investigations of hydrogen jet flames at high pressure N2 - In order to reduce the human footprint of CO2 emissions and limit global warming effects hydrogen combustion is becoming increasingly important. To enable fuel cells and gas turbines to operates this carbon free fuel, unprecedently large amounts of hydrogen need to be produced and safely transported and stored. The investigation of the effects of accidents involving hydrogen is therefore becoming of outmost importance. Since hydrogen is usually stored and transported under pressure, one scenario to be considered is the release of hydrogen from a leakage with subsequent ignition. The resulting jet flame must be characterized with respect to the thermal radiation emitted into the environment to define safety regulations. Various models that characterize the resulting flame shape and radiation already exist in the literature, but these are mainly based on empirical data from hydrocarbon jet flames.[1-4] To verify these models, a H2 Jet Flame project conducted at BAM, is investigating the safety of momentum driven hydrogen jet flames. For this purpose, large-scale tests are carried out at the Test Site Technical Safety (BAM-TTS). The object of the investigations is to assess the effects of real scale release scenarios regarding flame geometry and the thermal radiation emitted. Parameters such as release angle, leakage diameter (currently 1 mm to 10 mm), pressure (currently up to max. 250 bar) and mass flow (up to max. 0.5 kg/s) are varied. In addition, influences such as the type of ignition, ignition location as well as delayed ignition can also be investigated. The gained knowledge will be compared with existing jet flame models, to validate these and identify a possible need for further development. In particular, the focus will be laid on the thermal radiation of hydrogen flames. The challenge here is the visualization and characterization of the flame geometry in an open environment. Visualization is performed using infrared (IR) camera systems from at least two viewing angles. Measurements of the heat radiation of jet flames, which can be found in the literature, are mostly based on unsteady outflow conditions. The experimental setup used here allows for the generation of a steady-state outflow for several minutes and thus a direct comparability with existing (steady-state) models. Furthermore, the tests can be carried out for comparative measurements with hydrocarbons (methane, etc.) as well as mixtures of hydrogen and hydrocarbons. T2 - European PhD Hydrogen Conference 2024 (EPHyC2024) CY - Gent, Belgium DA - 20.03.2024 KW - Thermal radiation KW - Release KW - Hydrogen KW - Jet flame PY - 2024 SP - 551 EP - 556 AN - OPUS4-59910 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bernardy, Christopher A1 - Habib, Abdel Karim A1 - Kluge, Martin A1 - Schalau, Bernd A1 - Kant, Hanjo A1 - Schulze, Marcel A1 - Orchini, Alessandro T1 - Sicherheitstechnische Untersuchungen von Wasserstoff Freistrahlflammen bei Hochdruck im Realmaßstab N2 - Wasserstoff als Energieträger gewinnt zunehmend an Bedeutung. Die Untersuchung von Störfallauswirkungen mit Wasserstoff rückt somit stärker in den Fokus. Da Wasserstoff meist unter Druck gelagert und transportiert wird, ist ein zu betrachtendes Szenario die Freisetzung aus einer Leckage mit anschließender Zündung. Die daraus resultierende Freistrahlflamme (Jet Flame) muss hinsichtlich der in die Umgebung emittierten Wärmestrahlung charakterisiert werden. In der Literatur existieren bereits verschiedene Modelle, welche jedoch vermehrt auf Daten aus Kohlenwasserstoffflammen mit geringem Impuls basieren. Zur Überprüfung dieser Modelle wird im Zuge des BAM internen H2 Jet Flame Projektes die sicherheitstechnische Untersuchung von impulsbehafteten Wasserstoff Freistrahlflammen vorgenommen. Hierfür finden Versuche im Realmaßstab auf dem Testgelände Technische Sicherheit der BAM (BAM-TTS) statt. Gegenstand der Untersuchungen ist die Beurteilung der Auswirkungen von realistischen Freisetzungsszenarien hinsichtlich der Flammengeometrie und der freigesetzten Wärmestrahlung. Dabei werden Parameter wie Freisetzungswinkel, Leckagedurchmesser (z.Zt. 1 mm bis 10 mm), Druck (z.Zt. bis max. 250 bar) und Massenstrom (bis max. 0,5 kg/s) variiert. Zusätzlich können auch Einflüsse wie Art der Zündung, Zündort sowie Zündung mit zeitlichem Verzug untersucht werden. Gewonnene Erkenntnisse werden mit den Ergebnissen bereits vorhandener Modelle verglichen und diese im Bedarfsfall weiterentwickelt. Insbesondere wird der Fokus auf die Modellierung der freigesetzten Wärmestrahlung von Wasserstoffflammen gelegt. Herausforderung dabei stellt die IR-Vermessung und Modellierung von Sichtmodellen der Flammen dar. Die Visualisierung der Flammengeometrie wird mit Hilfe mehrerer Infrarot Kamerasystemen (aus mindestens zwei Blickwinkeln) vorgenommen. Bisherige Messungen, die in der Literatur zu finden sind, basieren meist auf instationären Auströmbedingungen. Der hier verwendete Versuchsaufbau ermöglicht ein stationäres Ausströmen für mehrere Minuten und somit eine direkte Vergleichbarkeit mit den existierenden (stationären) Modellen. Weiterhin ist der Versuchsstand umrüstbar für Vergleichsmessungen mit Kohlenwasserstoffen (Methan etc.) sowie Mischungen aus Wasserstoff und Kohlenwasserstoffen. T2 - Magdeburg-Köthener Brandschutz- und Sicherheitstagung 2024 CY - Magdeburg, Germany DA - 14.03.2024 KW - Wärmestrahlung KW - Wassersoff KW - Freistrahlflamme PY - 2024 SN - 978-3-948749-42-2 SP - 137 EP - 146 CY - Magdeburg AN - OPUS4-59912 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bernardy, Christopher A1 - Habib, Abdel Karim A1 - Kluge, Martin A1 - Schalau, Bernd A1 - Kant, Hanjo A1 - Schulze, Marcel A1 - Orchini, Alessandro T1 - Experimental Investigation of Large-Scale Hydrogen Diffusion Jet Flames N2 - Hydrogen is a promising alternative to natural gas in industrial energy applications to limit global warming. However, wide application of hydrogen requires specific safety considerations taking into account that hydrogen is stored and transported under much higher pressure than natural gas. Thus, one scenario to be considered for hazard assessment is a sudden release of hydrogen from a leakage or safety valve and its subsequent ignition. For hydrocarbon flames, various jet flame models are available. However, hydrogen flames significantly differ from hydrocarbon flames in their combustion behavior, so that the applicability of these models to hydrogen has to be investigated. For that purpose, reals scale tests were carried out at the BAM Test Site Technical Safety. In these tests, the flame geometry and the thermal heat radiation were investigated for a release angle of 90°, for different release pressures (up to 220 bar) and mass flows (up to 0.175 kg/s). Most existing data on thermal radiation are based on unsteady flow conditions and/or still air, whereas the experiments carried out here ensure a constant mass flow under realistic free-field conditions (with wind influence). This allows a better comparability with the stationary jet flame models and assessment of wind influence on model predictions. A number of parameters such as the surface emissive power and the radiant heat fraction were determined. A detailed comparison of the obtained experimental results with literature radiation models was performed. Based on the investigations, empirical equations for modelling jet flames could be derived. T2 - Proceedings of ASME Turbo Expo 2025 Turbomachinery Technical Conference and Exposition CY - Memphis, Tennessee, USA DA - 16.06.2025 KW - Hydrogen release KW - Radiant heat fraction KW - Thermal radiation KW - Jet flame PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643401 DO - https://doi.org/10.1115/1.4070012 SN - 0742-4795 VL - 148 IS - 5 SP - 51008-1 EP - 51008-8 PB - ASME International AN - OPUS4-64340 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bernardy, Christopher A1 - Habib, Abdel Karim A1 - Kluge, Martin A1 - Schalau, Bernd A1 - Schulze, Marcel A1 - Kant, Hanjo A1 - Orchini, Alessandro ED - Di Benedetto, Almerinda ED - Portarapillo, Maria T1 - Investigation of the thermal radiation from hydrogen jet flames N2 - For industrial applications dealing with hydrogen, the definition of safety distances and the assessment of possible hazards emanating from releases is mandatory. Since hydrogen is usually stored and transported under pressure, one scenario to be considered is the momentum driven release of hydrogen from a leakage with subsequent ignition. In this scenario, the emitted heat radiation from the resulting jet flame to the surroundings has to be determined to define adequate safety distances. For hydrocarbon flames, different jet flame models are available to assess the hazards resulting from an ignited jet release. Since hydrogen flames differ from hydrocarbon flames in their combustion behavior, it has to be checked if these models are also applicable for hydrogen. To evaluate the accuracy of these models for hydrogen jet flames, tests at real-scale are carried out at the BAM Test Site for Technical Safety (BAM-TTS). Herein, the flame geometry and the heat radiation at defined locations in the surroundings are recorded for varying release parameters such as leakage diameter (currently up to 30 mm), release pressure (currently up to max. 250 bar) and mass flow (up to max. 0.5 kg/s). The challenge here is the characterization of the flame geometry in an open environment and its impact on the thermal radiation. Existing heat radiation data from the literature are mostly based on unsteady outflow conditions. For a better comparability with the steady state jet flame models, the experiments presented here are focused on ensuring a constant mass flow over the release duration to obtain a (quasi) stationary jet flame. In addition, stationary outflow tests with hydrocarbons (methane) were also carried out, which are intended to serve as reference tests for checking flame models based on hydrocarbon data. T2 - 15th International Symposium on Hazards, Prevention and Mitigation of Industrial Explosions (ISHPMIE) CY - Neaples, Italy DA - 10.06.2024 KW - Hydrogen KW - Release KW - Jet flame KW - Thermal radiation PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605107 DO - https://doi.org/10.5281/zenodo.12515710 VL - 2024 SP - 1322 EP - 1333 PB - Zenodo CY - Geneva AN - OPUS4-60510 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bernardy, Christopher A1 - Habib, Abdel Karim A1 - Kluge, Martin A1 - Schalau, Bernd A1 - Schulze, Marcel A1 - Kant, Hanjo A1 - Orchini, Alessandro ED - Ruggiero, Eric J. T1 - Experimental investigation of large-scale hydrogen diffusion jet flames N2 - Hydrogen is a promising alternative to natural gas in industrial energy applications which would serve the goal of limiting global warming. However, wide application of hydrogen requires specific safety considerations taking into account that hydrogen is stored and transported under much higher pressure than natural gas. Thus, one scenario to be considered for hazard assessment is a sudden release of hydrogen from a leakage or safety valve and its subsequent ignition. For hydrocarbon flames, various jet flame models are available. However, hydrogen flames significantly differ from hydrocarbon flames in their combustion behavior, so that the applicability of these models to hydrogen has to be investigated. For that purpose, reals scale tests were carried out at the BAM Test Site Technical Safety. In addition, hydrocarbon jet flames (methane) were investigated. In these tests, the flame geometry and the thermal heat radiation were investigated for a release angle of 90°, for different release pressures (up to 220 bar) and mass flows (up to 0.175 kg/s). While existing heat radiation data from the literature are mostly based on unsteady outflow conditions and/or releases in still air, the experiments presented here are focused on ensuring a constant mass flow over the release duration under realistic free field conditions (with wind influence). This allows a better comparability with the stationary jet flame models and assessment of wind influence on model predictions. A number of parameters such as the surface emissive power of the jet flame and the radiant heat fraction were determined. A detailed comparison of the obtained experimental results with literature radiation models was performed. Good agreement between experimental and literature data was found for hydrogen whereas significant differences were identified for methane. Based on the investigations, empirical equations for modelling jet flames could be derived. T2 - American Society of Mechanical Engineers - Turbomachinery Technical Conference & Exposition GT2025 CY - Memphis, TN, USA DA - 16.06.2025 KW - Hydrogen release KW - Jet flame KW - Radiant heat fraction KW - Thermal radiation PY - 2025 SN - 978-0-7918-8877-3 DO - https://doi.org/10.1115/GT2025-FM2 SP - 1 EP - 11 PB - The American Society of Mechanical Engineers CY - Livingston AN - OPUS4-64098 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bernardy, Christopher A1 - Habib, Abdel Karim A1 - zur Nedden, Philipp Maximilian A1 - von Saldern, Jakob Georg Raimund A1 - Beuth, Jan Paul A1 - Orchini, Alessandro T1 - Thermal Radiation Of Inclined Large Scale Hydrogen Jet Flames N2 - In order to assess the thermal radiation emanating from hydrogen jet flames, experiments under real scale conditions were carried out at the Test Site Technical Safety of BAM. Herein, the behavior of inclined hydrogen jet flames was investigated. The aim of the work is to determine the Surface Emissive Power (SEP) and radiant heat fraction of these flames and to provide a reliable dataset for model evaluation purposes. Since the aforementioned values are not directly measurable, the incident heat radiation was measured at defined distances from the flame, as well as the flame’s shape and size. The required values were then derived from these measurements. The hydrogen releases ranged from 0.0125 kg/s to 0.175 kg/s with a 30 mm orifice. The mass flows were held constant during the releases, nevertheless a transient behavior of the flame could be observed since the experiments were carried out under open field conditions, with unsteady wind fields. In the literature, the flame lengths are often determined using visible light imaging, either by injecting coloring substances in the low light emitting hydrogen jet flame or by carrying out the measurements in darkness. In this work the jet flames were visualized using infrared (IR) and OH* imaging. The recorded flame shapes and resulting flame lengths are compared. Results from this showed that the flame lengths determined with OH* and IR recordings differ greatly. A flame length ratio lf OH*/lf IR in the range of 0.47–0.62 can be found. In addition, the SEP differ also in the range of 10 kW/m2–16 kW/m2 (IR) and 40 kW/m2–80 kW/m2 (OH*) for hydrogen jet flames due to differences in the determined flame surface. Conclusions regarding the determined xRAD values for IR and OH* result in approximately the same range of 0.031–0.043. T2 - 11th Iinternational conference on hydrogen safety 2025 CY - Seoul, Republic of Korea DA - 22.09.2025 KW - Hydrogen safety KW - Jet flames KW - Thermal radiation KW - Large scale experiment PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655181 DO - https://doi.org/10.58895/hysafe.27 SN - 2943-5935 VL - 3 IS - 1 SP - 39 EP - 50 PB - Karlsruhe Institute of Technology Library AN - OPUS4-65518 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bernardy, Christopher A1 - Habib, Abdel Karim A1 - zur Nedden, Philipp Maximilian A1 - von Saldern, Jakob Georg Raimund A1 - Beuth, Jan Paul A1 - Orchini, Alessandro ED - Carcassi, Marco T1 - Thermal radiation of inclined large scale hydrogen jet flames N2 - In order to assess the thermal radiation emanating from hydrogen jet flames, experiments under real scale conditions were carried out at the Test Site Technical Safety of BAM. Herein, the behavior of inclined hydrogen jet flames was investigated. The aim of the work is to determine the Surface Emissive Power and radiant heat fraction of these flames and to provide a reliable dataset for model evaluation purposes. Since the aforementioned values are not directly measurable, the incident heat radiation was measured at defined distances from the flame, as well as the flame's shape and size. The required values were then derived from these measurements. The hydrogen releases ranged from 0.005 kg/s to 0.175 kg/s with a 30 mm orifice. The mass flows were held constant during the releases, nevertheless a transient behavior of the flame could be observed since the experiments were carried out under open field conditions, with unsteady wind fields. In the literature, the flame lengths are often determined using visible light imaging, either by injecting coloring substances in the low light emitting hydrogen jet flame or by carrying out the measurements in darkness. In this work the jet flames were visualized using infrared (IR) and OH* imaging. The recorded flame shapes and resulting flame lengths are compared. Results from this showed that the flame lengths determined with OH* and IR recordings differ greatly. A flame length ratio l_(f OH*)/l_(f IR) in the range of 0.47-0.62 can be found. In addition, the SEP differ also in the range of 10 kW/m²-16 kW/m² (IR) and 40 kW/m²-80 kW/m² (OH*) for hydrogen jet flames due to differences in the determined flame surface. Conclusions regarding the determined x_(RAD )values for IR and OH* result in approximately the same range of 0.031-0.043. T2 - 11th International conference on hydrogen safety 2025 CY - Seoul, Republic of Korea DA - 22.09.2025 KW - IR and OH* measurement KW - Hydrogen release KW - Inclined jet flame KW - Thermal radiation KW - Radiant heat fraction PY - 2025 SN - 979-12-243-0274-2 SP - 837 EP - 849 AN - OPUS4-65362 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schalau, Bernd A1 - Bernardy, Christopher A1 - Habib, Abdel Karim T1 - Modellierung von Wasserstoff - Freistrahlflammen N2 - Bei der Freisetzung von Wasserstoff aus Ausbläsern kann nicht ausgeschlossen werden, dass es zu einer Selbstentzündung und der Bildung einer Freistrahlflamme kommt. Als Auswirkungen für die Umgebung sind der Explosionsüberdruck bei der Zündung und die Wärmestrahlung im Rahmen einer Gefährdungsbeurteilung zu betrachten. In der Literatur sind verschiedene Ansätze für die Modellierung einer Wasserstoff-Freistrahlflamme zu finden, wobei viele sich mit der Berechnung der Flammenlänge befassen. Experimentelle Freifeld-Untersuchungen unter Windeinfluss und entsprechende Modellierungen der Wärmestrahlung in der Umgebung einer Wasserstoff-Freistrahlflamme liegen nur wenig vor. In der Bundesanstalt für Materialforschung und -prüfung BAM sind solche Experimente durchgeführt worden und die daraus abgeleitete Modellierung wird im Folgenden vorgestellt. KW - Freistrahlflamme KW - Auswirkungsbetrachtung PY - 2025 SN - 2191-007 VL - 15 IS - 05-06 SP - 16 EP - 24 CY - Düsseldorf AN - OPUS4-63709 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -