TY - GEN
T1 - Analysis of Hydrogen Diffusion Ignition in Oxygen-Nitrogen Mixtures
AU - Nassar, Odai
AU - Oruganti, Surya Kaundinya
AU - Alves, Marcel Martins
AU - Kudriakov, Sergey
AU - Studer, Etienne
AU - Ishay, Liel
AU - Kozak, Yoram
N1 - Publisher Copyright:
© 2023 Proceedings of the 20th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2023. All rights reserved.
PY - 2023
Y1 - 2023
N2 - Extreme accidental scenarios in nuclear power plants (NPPs) might involve hydrogen formation and pressurized release into the containment building, which eventually may lead to an unintended explosion. Thus, fundamental understanding of the complex physical mechanisms associated with such accidental explosions is necessary for their prevention and mitigation. In the present study, we analyse the mitigating effect of nitrogen dilution on diffusion ignition of hydrogen in air. In particular, we investigate the self-ignition of a diffusion layer behind a shock wave for the initial pressure ratio of 700 between hydrogen and atmospheric air. Numerical simulations are carried out via the open source code Ember for a 1-D unsteady diffusion-reaction problem. Pure H2 is considered as high-pressure gas and three different gas compositions are considered as low-pressure gas - 21% of O2 with 79% of N2, 12% of O2 with 88% of N2, and 6% of O2 with 94% of N2. For all the cases, it is observed that O2 is converted into OH and H2O around the same location within the diffusion layer. However, the ignition delay time is longer for the cases of 12% of O2 and 6% of O2 than for pure-air case by less than 0.06 µs and 0.50 µs, respectively.
AB - Extreme accidental scenarios in nuclear power plants (NPPs) might involve hydrogen formation and pressurized release into the containment building, which eventually may lead to an unintended explosion. Thus, fundamental understanding of the complex physical mechanisms associated with such accidental explosions is necessary for their prevention and mitigation. In the present study, we analyse the mitigating effect of nitrogen dilution on diffusion ignition of hydrogen in air. In particular, we investigate the self-ignition of a diffusion layer behind a shock wave for the initial pressure ratio of 700 between hydrogen and atmospheric air. Numerical simulations are carried out via the open source code Ember for a 1-D unsteady diffusion-reaction problem. Pure H2 is considered as high-pressure gas and three different gas compositions are considered as low-pressure gas - 21% of O2 with 79% of N2, 12% of O2 with 88% of N2, and 6% of O2 with 94% of N2. For all the cases, it is observed that O2 is converted into OH and H2O around the same location within the diffusion layer. However, the ignition delay time is longer for the cases of 12% of O2 and 6% of O2 than for pure-air case by less than 0.06 µs and 0.50 µs, respectively.
KW - Containment
KW - Diffusion ignition
KW - Hydrogen
KW - Nitrogen dilution
KW - Pressurized jet release
UR - http://www.scopus.com/inward/record.url?scp=85202942231&partnerID=8YFLogxK
U2 - 10.13182/NURETH20-40194
DO - 10.13182/NURETH20-40194
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AN - SCOPUS:85202942231
T3 - Proceedings of the 20th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2023
SP - 3994
EP - 4005
BT - Proceedings of the 20th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2023
PB - American Nuclear Society
T2 - 20th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2023
Y2 - 20 August 2023 through 25 August 2023
ER -