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The Safe EscapeFire & Smoke Simulation for Public Transport
> Erwin Schnell, Peter Bailey
Gruner AG, Basle, Switzerland
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Gruner AG
> One of most important engineering groups in CH
> Founded 1862, 12 subsidiary companies, 600+
people in Austria, Switzerland, Germany
> E. Gruner 1947 had foresight to conceive a
Gotthard Base Tunnel for year 2000
> Work in area of Safety – Fire Protection, Tunnel
Safety
> collaboration in developing F&S Wizard
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Fire & Smoke
> what does Fire & Smoke modelling mean?
> Various models, eg. estimate fire spread, combustion rate/materials
> Variables broken down to most important, generalised and
dimentioned accordingly
> Smoke control
> Volumetric addition of energy (Heat Release Rate, HRR) [W/m3]
> Smoke release, yield, Y [g/g], corresponding to HRR (volumetric)
> Concentration (passive scalar) extinktion (visibility) [/m]
> * Bernhard Rawyler, officer in charge, Biel Fire Brigade
*
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Compartment Fire
> Flow induced by fire in a compartment, Steckler, Quintiere, Rinkinen, National Bureau of Standards,
Washington, DC, 1984
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Fire & Smoke in CCM+
> Dimensioning/fire characteristics(transient) real fire tests define:
> HRR = αt2 , smoke release = Y.HRR/HC . ρ
> Validation : empirical tests, eg. Steckler, chemistry of fire, deduced
from damage caused in real situation + $
> 28MW experiment difficult to set up !
> * vfdb TB 04-01(5/2009) pg 85
> + Eureka-Project EU 499 : FIRETUN, Nov. 1995. Fires in Transport Tunnels, Report on Full-Scale Tests.
Editor : Studiengesellschaft Stahlanwendung e.V., Düsseldorf
> $ Memorial Tunnel Fire Ventilation Test Program, Test Report, Massachusetts Highway Dept. and Fed.
Highway Admin, Nov. 1995
*
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Fire & Smoke in CCM+
> Important parameter is heat content
> Dynamics of the smoke containing air hugely effected by heat,
and temperature differences – expansion/buoyancy
> Heat addition/loss from system is key!
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Tunnel Flow with Heat Source
> Thermal effects now alter entry length, "backlayering"
> Fire = addition of energy/temperature, decrease in pressure at fire,
blockage/pressure increase, due to plume/buoyancy
> New dynamics, "ceiling jet"
> conservation of mass/momentum/energy addition of heat source
> as with any numerical model important to appreciate limits of validity and
conclusions possible to be drawn
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Typical Rail Tunnel Scenarios
> Modern longest road/rail/metro tunnels, of order ~20-50km
length
> Gotthard Base tunnel, 2017, 57km
> Twin bore tunnels, having connecting tunnels every ~500m
> Longest tunnels have emergency stations
> (50km @ 230km/h ~ 13mins)
> Expect differing atmospheric conditions at portals
> 1D tools provide boundary conditions
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Cross Passage Critical Velocity
> Critical Velocities: Tunnel / Cross Passage
> Cross Passage Critical Velocity:
> High enough to avoid upstream flow of smoke
> Low to avoid disruption of smoke stratification
> Minimum Flow Velocity Through Open Cross Passages in Twin Bore Rail Tunnels, Langner,
Bopp, Bailey, Proceedings 5th Int. Conf. Tunnel Safety and Ventilation, Graz 2010, to appear.
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Emergency Station
> Need a safe area, zero smoke/temperature entrance, until
rescue services arrive
> Need continued smoke control for arrival of fire service
> Dimensioned according to critical velocities
> Avoid backlayering
> Avoid smoke beyond escape doors
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Emergency Station
> Extraction / Air feed systems
> lower level : fresh cool air
> upper level : hot gas extraction
> Greater extraction to avoid
backlayering in main tunnel
> Train length ~ 400m
> Main tunnel area ~ 50m2
> Station x,y,z : 500m, 50m, 10m
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Smoke Visualisation
> Iso contours of
extinktion
Burning_carriage
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Smoke Visualisation, fire towards rear of train
> v 4.06 update : 2 passive scalars
> distinguish smoke trail following train and smoke from fire
Platform_view
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Where to sit ?
> Smoke at 2.0m from foot way :
Protection_goal
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