Modelling of car park fires

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Modelling of car park fires

• Jelle Agema

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Modelling of car park fires

• Contents
• Car park ventilation systems
• Parameters for the model
• Results

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Thrust ventilation

• Top view

Side view
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Jet fans
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Typical car park
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Car fire

• Production of
• Heat
• Mass
• Smoke
• Using InForm SOURCE statements

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Fire curve
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Use of the CFDs

• Verification of the system for the fire brigade
• Illustration of the functioning of the system to
  the customer
• Optimisation of the system

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Requirements
Usually visibility of 30 meters 45 minutes after
the fire has started Possible additional
requirements Sight length gt 30 meters in the
direction of the fire Acceptable temperatures for
firemen
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For a worst case scenario

• inlet outlet

openings
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Typical car park data

• Area of 50 x 50 m2 to 200 x 200 m2
• One or two openings (entrances)
• Exhaust
• Inlet
• 8 to 30 jet fans (/- 20 m/s)
• 10 to 30 air changes per hour (Vaverage /- 1.0
  m/s)

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Modelling (assumptions, parameters)

• Phoenics Flair
• Jet fan model
• Cartesian grid,
• 250,000 1 000 000 cells
• Usually /- 150 iterations until convergence
• Hybrid differencing

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Modelling (assumptions, parameters)

• K-e model, buoyancy modified (highly turbulent
  air flow and free air stream)
• No radiation
• Smoke production, according to Smoke potential
  of 400 m-1/(kg/m3)
• Jet fans using air speeds from measurements

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Validation

• Fire Tests TNO Delft 1998Car Park Fleerde
  Amsterdam
• Other CFDs

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Real test case
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Animation
ja_at_novenco.nl

• Jelle Agema