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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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