Experimental and Analytical Studies of the Formation of Fire and Explosive Vapor Clouds in the Atmosphere during Leaks and Spills of Liquid Hydrogen


Annotation:

Experimental and numerical studies of the process of formation of fire-explosive steam-air clouds in the atmosphere during leaks and spills of liquid hydrogen were carried out. Within their framework, the tasks were performed to determine the size and lifetime of a hydrogen-air cloud with a hazardous concentration of hydrogen from the point of view of explosion and fire hazard (including at the boundary of a visible cloud), and the relationship between the temperature and concentration of combustible gas in a gas-air cloud; studying the effect of cloud temperature on its parameters, the role of atmosphere involvement in the convective hydrogen jet; establishing the influence of moisture content in the atmospheric cloud and the mobility of the environment (wind exposure) on the dynamics of changes in the level of its fire and explosion hazard. It is shown that the humidity of the environment affects the concentration of hydrogen at the boundary of the visible cloud, and, consequently, its fire and explosion hazard.

The assessment of the influence of humidity on the parameters of the studied turbulent convective jet indicates that the rate of change in the mass concentration of hydrogen on the axis of the low-temperature jet from the height of ascent depends on the humidity of the medium. The higher the humidity, the sharper the decrease in the mass concentration of hydrogen along the height of the convective jet becomes. 

In accordance with the calculations, the time for dissipation of a cloud to a fireproof hydrogen concentration in the presence of moisture condensate is reduced by 30 %, and the dissipation time to an explosive concentration of hydrogen is reduced by about 20 %.

The coefficient of air involvement α in convective jets of hydrogen-air mixtures with positive buoyancy is 0.12 considering the real enthalpy and absolute humidity of the surrounding air of 15 g/m3 (90 % humidity at 20 °C). This coefficient can be used in the calculations of turbulent convective jets formed during stationary hydrogen evaporation. 

Wind at low speeds leads to an increase in the maximum transverse dimensions of the cloud, regardless of the concentration in the hydrogen jet, and at high speeds, to their decrease. For emergency hydrogen spills, the most dangerous case when a hydrogen-air cloud of large volumes is formed in the atmosphere, is the case with zero humidity and no wind (in a wide range of values of the initial mass flow of hydrogen: 0.1–100 kg/s).

References:
1. Chuguev A.P., Bolodyan I.A., Nekrasov V.P., Fedorinov M.V., Sychev A.N. Explosive Combustion of Hydrogen-Air Mixtures Large Volumes in the Open Atmosphere. Bezopasnost Truda v Promyshlennosti = Occupational Safety in Industry. 2021. № 12. pp. 24–28. (In Russ.). DOI: 10.24000/0409-2961-2021-12-24-28
2. Bolodyan I.A., Vogman L.P., Nekrasov V.P., Mordvinova A.V. Experimental Research of the Combustion of Spherical Hydrogen-Air Mixtures in an Open Space under the Influence of Slowing and Accelerating Factors. Bezopasnost Truda v Promyshlennosti = Occupational Safety in Industry. 2022. № 1. pp. 33–38. (In Russ.). DOI: 10.24000/0409-2961-2022-1-33-38
3. Bolodyan I.A., Vogman L.P. Experimental Studies of Cryogenic Liquids (Fuels) Spills. Bezopasnost Truda v Promyshlennosti = Occupational Safety in Industry. 2022. № 8. pp. 13–18. (In Russ.). DOI: 10.24000/0409-2961-2022-8-13-18
4. Lack A.W., Gaathaug A.V., Vaagsaether K. Pressure peaking phenomena: Unignited hydrogen release in confined spaces — Large scale experiments. International Journal of Hydrogen Energy. 2020. Vol. 45. Iss. 56. pp. 32702–32712. DOI: 10.1016/j.ijhydene.2020.08.221
5. Pitts W.M., Yang J.C., Blais M., Joyce A. Dispersion and burning behavior of hydrogen released in a full-scale residential garage in the presence and absence of conventional automobiles. International Journal of Hydrogen Energy. 2012. Vol. 37. Iss. 22. pp. 17457–17469. DOI: 10.1016/j.ijhydene.2012.03.074
6. Marshall V. Major Chemical Hazards. Moscow: Mir, 1989. 672 p. (In Russ.).
7. One Hundred Largest Losses — A Thirty Year Review of Property Damage Losses in the Hydrocarbon Chemical Industries (OHL-9-86-71). Chicago: Marsh and McLennan, 1986.
8. Wiekema B.J. Vapour cloud explosions — an analysis based on accidents: Part II. Journal of Hazardous Materials. 1984. Vol. 8. Iss. 4. pp. 313–329. DOI: 10.1016/0304-3894(84)87028-4
9. Chepegin I.V. Analysis of the causes of accidents with natural gas explosions. Vestnik Kazanskogo tekhnologicheskogo universiteta = Bulletin of the Technological University. 2014. Vol. 17. № 10. pp. 245–248. (In Russ.).
10. Witcofsky R.D, Chirivella J.E. Experimental and analytical analyses of the mechanisms governing the dispersion of flammable clouds formed by liquid hydrogen spills. International Journal of Hydrogen Energy. 1984. Vol. 9. Iss. 5. pp. 425–435. DOI: 10.1016/0360-3199(84)90064-8
11. Gostintsev Yu.A., Solodovnik A.F., Lazarev V.V., Shatskikh Yu.V. Turbulent thermal in a stratified atmosphere: preprint. Chernogolovka: IKhF AN SSSR, 1985. 46 p. (In Russ.).
12. Kestenboym Kh.S., Makhviladze G.M., Fedotov A.P. Evolution of a cloud of light gas formed during spills of cryogenic fuel. Moscow: IPM, 1989. 48 p. (In Russ.).
13. Makeev V.I., Pleshakov V.F. To the assessment of the potential danger of spills of liquid hydrogen in the room. Pozharnaya profilaktika: sb. nauch. tr. (Fire prevention: collection of scientific papers). Iss. 13. Moscow: VNIIPO, 1977. pp. 3–15. (In Russ.).
14. SP 12.13130.2009. Definition of categories of premises, buildings and outdoor installations for explosion and fire hazard. Available at: https://files.stroyinf.ru/Data2/1/4293830/4293830316.pdf (accessed: July 1, 2022). (In Russ.).
DOI: 10.24000/0409-2961-2022-9-7-13
Year: 2022
Issue num: September
Keywords : fire and explosion hazard combustible gas emergency spillage температура experimental studies hydrogen-air cloud humidity mobility participation factor
Authors:
  • Bolodyan I.A.
    Bolodyan I.A.
    Dr. Sci. (Eng.), Prof., Chief Research Associate, FGBU VNIIPO EMERCOM of Russia, Balashikha, Russian Federation
  • Vogman L.P.
    Vogman L.P.
    Dr. Sci. (Eng.), Chief Research Associate, FGBU VNIIPO EMERCOM of Russia, Balashikha, Russian Federation