Thermal radiation hazards from LPG-fireballs

Jouni Partanen, Matti Vuorio

Research output: Book/ReportReportProfessional

Abstract

Turbulently burning fuel-rich fireballs cool both by thermal radiation and by mixing with ambient cold air. Both mechanisms have been considered important. In this work we first study their relative effectiveness By re-analyzing published, small scale experimental results and by two simple analytical models, which take into account only one of the cooling mechanisms at a time. The models indicate that mixing dominates over radiation. Detailed analytical calculations of thermal radiation are prohibitively complicated due to the fact that the temperature of the fireball, including its effective surface temperature, can not be determined by averaging in spite of the strong turbulence present. However, using some plausible assumptions we are able to extrapolate the empirical, thermally radiating fraction of the energy from experimentally available firehall sizes to such larger masses that are relevant in industrial accidents. This is done by scaling the relevant parameters (fireball radius, its burning and cooling time) with the released fuel mass Mf. The radiating fraction turns out to be a weakly decreasing function of the mass (~Mf-1/6). In the end we estimate the health hazards from thermal radiation to people at different distances as a function of Mf.
Original languageEnglish
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Number of pages29
ISBN (Print)951-38-2025-4
Publication statusPublished - 1984
MoE publication typeD4 Published development or research report or study

Publication series

NameTutkimuksia / Valtion teknillinen tutkimuskeskus
PublisherVTT
Volume304

Fingerprint

radiation hazards
fireballs
thermal radiation
burning time
cooling
accidents
hazards
surface temperature
health
turbulence
scaling
radii
air
radiation
estimates
temperature
energy

Keywords

  • LPG-fireballs
  • thermal radiation

Cite this

Partanen, J., & Vuorio, M. (1984). Thermal radiation hazards from LPG-fireballs. Espoo: VTT Technical Research Centre of Finland. Valtion teknillinen tutkimuskeskus. Tutkimuksia - Research Reports, No. 304
Partanen, Jouni ; Vuorio, Matti. / Thermal radiation hazards from LPG-fireballs. Espoo : VTT Technical Research Centre of Finland, 1984. 29 p. (Valtion teknillinen tutkimuskeskus. Tutkimuksia - Research Reports; No. 304).
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Partanen, J & Vuorio, M 1984, Thermal radiation hazards from LPG-fireballs. Valtion teknillinen tutkimuskeskus. Tutkimuksia - Research Reports, no. 304, VTT Technical Research Centre of Finland, Espoo.

Thermal radiation hazards from LPG-fireballs. / Partanen, Jouni; Vuorio, Matti.

Espoo : VTT Technical Research Centre of Finland, 1984. 29 p. (Valtion teknillinen tutkimuskeskus. Tutkimuksia - Research Reports; No. 304).

Research output: Book/ReportReportProfessional

TY - BOOK

T1 - Thermal radiation hazards from LPG-fireballs

AU - Partanen, Jouni

AU - Vuorio, Matti

PY - 1984

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N2 - Turbulently burning fuel-rich fireballs cool both by thermal radiation and by mixing with ambient cold air. Both mechanisms have been considered important. In this work we first study their relative effectiveness By re-analyzing published, small scale experimental results and by two simple analytical models, which take into account only one of the cooling mechanisms at a time. The models indicate that mixing dominates over radiation. Detailed analytical calculations of thermal radiation are prohibitively complicated due to the fact that the temperature of the fireball, including its effective surface temperature, can not be determined by averaging in spite of the strong turbulence present. However, using some plausible assumptions we are able to extrapolate the empirical, thermally radiating fraction of the energy from experimentally available firehall sizes to such larger masses that are relevant in industrial accidents. This is done by scaling the relevant parameters (fireball radius, its burning and cooling time) with the released fuel mass Mf. The radiating fraction turns out to be a weakly decreasing function of the mass (~Mf-1/6). In the end we estimate the health hazards from thermal radiation to people at different distances as a function of Mf.

AB - Turbulently burning fuel-rich fireballs cool both by thermal radiation and by mixing with ambient cold air. Both mechanisms have been considered important. In this work we first study their relative effectiveness By re-analyzing published, small scale experimental results and by two simple analytical models, which take into account only one of the cooling mechanisms at a time. The models indicate that mixing dominates over radiation. Detailed analytical calculations of thermal radiation are prohibitively complicated due to the fact that the temperature of the fireball, including its effective surface temperature, can not be determined by averaging in spite of the strong turbulence present. However, using some plausible assumptions we are able to extrapolate the empirical, thermally radiating fraction of the energy from experimentally available firehall sizes to such larger masses that are relevant in industrial accidents. This is done by scaling the relevant parameters (fireball radius, its burning and cooling time) with the released fuel mass Mf. The radiating fraction turns out to be a weakly decreasing function of the mass (~Mf-1/6). In the end we estimate the health hazards from thermal radiation to people at different distances as a function of Mf.

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KW - thermal radiation

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Partanen J, Vuorio M. Thermal radiation hazards from LPG-fireballs. Espoo: VTT Technical Research Centre of Finland, 1984. 29 p. (Valtion teknillinen tutkimuskeskus. Tutkimuksia - Research Reports; No. 304).