Combustion Limits in Fire and Explosion Hazards

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Combustion Limits in Fire and Explosion Hazards
CONFIDENTIAL

• Geoff Chamberlain and Jonathan Puttock, Major
  Hazards Management Team,
• Shell Global solutions UK, Chester.

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Early Experiments G. Kalghatgi, 1981

• Determined the blow out limits for subsonic
  gases.
• Established universal stability curve.

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Experimental results Mach No. v burner diameter
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Flame stability in still air natural gas
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Experiments in crosswinds lifted flames

• Sheffield University wind tunnel at Buxton
• Burners 2-20 mm, crosswinds up to 8m/s
• Methane, propane, Butagas (propane/butane mix),
  ethylene
• Results non-dimensionalised using the grouping
• Flames are less stable when burner tilted away
  from wind

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Flame stability lifted flames in crosswind
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VideoWake stabilised flames
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The Universal Flame Stability Map
CONFIDENTIAL
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Wake stabilised flames effect of burner tilt

• Burner tilted away from flame, flame is more
  stable opposite effect with lifted flames.

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Bradley et al simulation heat release contours
MW/m3. Jet mean velocity 20m/s, crosswind 5.5
m/s. 10mm diam.CMC flamelet combustion model.
HPCx Daresbury.
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Bradley et al simulation heat release contours
and velocity vectors close to burner tip.
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Flammability Limits Fuel/air/water vapour
system. Flame extinction and oscillatory flames
in compartments.
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