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SC-GS/PI
Computer Fluid Dynamic Simulation of
Fire and Evacuation Scenarios for Large
Experiments of Physics
Fabio Corsanego
SC-GS/PI
5th HEP Technical Safety Forum at SLAC
11-15 Apr 2005
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Topics
•
•
•
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SC-GS/PI
Introduction
CFD Codes
Validation
Applications
• Evacuation Codes
• Validation
• Applications
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How to assess fires
..let’s begin with the answer which we need; we want to know:…
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Gas Temperature slice plot
Gas Velocity vector plot
–
…For structural integrity
Walls and objects Surface
Temperature plot
• Long term wall
temperatures
• Hot gases temperatures
– …For life protection
• Early stage visibility
• Smoke dilution &
composition
• Gas temperatures
• (Radiant heat)
Mixture fraction Iso-surface plot
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How to assess fires (continued)
…a glance at the CFD method…
SC-GS/PI
The idea is :
– To run fully instrumented small scale real fire tests
(record fire power, T, p, soot, chemical species and concentration)
– to obtain results by interpolation of the real fire tests by means of
semi-empirical equation
Bigger precision and extrapolation of the small scale tests are
possible, to a certain extent (*), with Computational Flow Dynamic
(CFD)
(*) CFD growing precision and validation
means chance to downsize real test on materials
and money saved!
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Market Survey CFD Codes
(most referenced)
SC-GS/PI
Here are reported the most referenced &used CFD codes for Smoke transport-diffusion modeling
Dedicated
Gen.Purpose
FDS – (National Institute of Science and Technology –MD-US) (free)
Phoenics (Concentr. Heat and Momentum Ldt, GB) (100-2000eu)
Fluent (Fluent Inc. GB)
(price requested)
Flow3d (Flow Science Inc. NM-US)
Smartfire (University of Greenwich)
(2500eu edu)
Jasmine (Ies Limited GB)
(12000eu )
Sofie (University of Cranfield – GB)
(150eu)
CFX
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Validation
Validation effort at CERN and elsewhere on FDS2
Heiss Dampf Nuclear Reactor
at Karlsrhue
– ~50, fully instrumented oil,
propane, cables fire tests in
the dismantled reactor
vessel (20m large, 50 m high)
– FDS2 was back-validated
against these data at
Maryland University
Large scale test, well representative
of large experiment halls
SC-GS/PI
Memorial Tunnel Fire Test in
US
– ~100 fully instrumented oil fire
and ventilation tests
– FDS2 was back-validated
against these data at CERN
Long tunnel test, well representative
of Accelerator Tunnels
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FDS2
Validation
Heiss-Dampf
Reaktor
Karlsruhe
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Gasoil 2-4 MW
fire
(Test T52)
Propane 1
MW fire
(Test T51)
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HDR Propane
TEST T51
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Data comparison
~5%
~11%
FIRE room ceiling level layer
Doorway ceiling level layer
FIRE room floor level layer
Doorway temperature profile
~15%
~100%
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HDR TEST T52 OIL 2 MW
Data comparison
Fire room temperature
~27%
SC-GS/PI
More on the geometry
O2 ~ 8%
Upper Hatch temperature
Doorway temperature
~45%
~12%
Doorway velocity
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~14%
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FDS2 MEMORIAL TUNNEL FIRE TEST VALIDATION
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8m high
The Memorial tunnel test program has provided a
huge amount of raw data on road tunnel fire
Flight view inside tunnel
Tests
8m large
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CASE T501: 20 MW Natural Ventilation – (Temperature)
16’ from ignition TEMPERATURES
OBSERVED:
SC-GS/PI
~150-300F = 80-150C
FDS2 RESULT
~150-300F = 80-150C
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Validation Overall Judgment
SC-GS/PI
The average results of the FDS2 in different situations(*) is as follows :
– Long term quasi steady Gas temperatures
• errors of the order of 20-30% of the DT
– Gas Concentration
• large errors, of ~ 1 order of magnitude
– Velocity of transients, like smoke layers descent and movement
• errors of the order of 40-60 %.
(*)different
situations:
•small room-small fire,
•small room-big fire,
•high bay-small fire,
•high bay-big fire, tunnel fire,
•pre-flashover, post-flashover,
•poor ventilation, rich ventilation,
•etc……!!!!!!
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Evacuation Simulation M. Survey
SC-GS/PI
Evacuation simulation codes:
• Simulex (I.E.S. International)
– License 2500€/yr
• Exodus 3D Greenwich University
(Fire Safety Group)
– License 5000 €/yr
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What we have to assess on fires: (continued)
‘…The construction works must be designed and built in such a way that in the event of an outbreak of fire:..
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–
…(d) occupants can leave the
construction works or be rescued
–
…(e) the safety of rescue teams is
taken into consideration
Will occupants leave the structure before the smoke/fire
produces untenable conditions?
Ship muster point video
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Exodus Validation References
SC-GS/PI
•
The Validation of Evacuation Models. Authors: E Galea. CMS Press, Paper No.
97/IM/22, ISBN 1 899991 22 0, 1997
•
The EXODUS Evacuation Model Applied to Building Evacuation Scenarios. Authors:
M Owen, E Galea, P Lawrence. Journal of Fire Protection Engineering 1996, Vol.8(2),
pp 65-86
•
The Collection and Analysis of Pre-Evacuation Times from Evacuation Trials and their
Application to Evacuation Modelling”. Gwynne S, Galea E.R., Parke J, Hickson J. Fire
Technology, Kluwer Associates, US, pp173-195, vol 39, number 2, 2003.
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SC-GS/PI
APPLICATIONS AT CERN
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The fire
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•Parabolic ramping fire power 0 -> 5MW
then steady
•Two different growth rates ( 5 MW in 700s ,
1500s)
•Located in 3 different position (bottom, top,
side)
•6 different runs per each experimental
cavern
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ATLAS
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SC-GS/PI
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Atlas Fires Locations
SC-GS/PI
In front of one exit
Under Detector
Top of Detector
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ATLAS Videos
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ATLAS THE
CONSTRUCTION OF THE
MODEL2.avi
ATLASLARGE.avi
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ATLAS Slices
(Fire under det. 5Mw 300s)
SC-GS/PI
t=150 s Smoke fills upper level
t=100 s
t=250-300s Smoke at level of upper
exits
t=200 s Smoke starts to descend
on upper gangways
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CMS
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SC-GS/PI
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Smoke development and transport within the
cavern
SC-GS/PI
CMS model showcase
CMS Fire Under Detector 5 MW
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Smoke layer position on the xz plane of the cavern
3rd level gangway flooded by smoke
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t=3’
t=5’
1st level gangway flooded by smoke
t=7’
2rd level gangway flooded by smoke
t=6’
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Evacuation modelling
SC-GS/PI
100 people in CMS
130 people in ATLAS
Snapshots of the CMS Model
Snapshot of the Atlas
Evacuation Simulation
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Results Overview ATLAS
SC-GS/PI
ATLAS:
Smoke propagation to exit level gangways:
300s (medium propagation) to 480s (moderate
propagation)
Evacuation Time: [120s for discovery] + 90to160s=
210s to 280s
Evacuation Validated
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Results Overview CMS
SC-GS/PI
ATLAS:
Smoke propagation to exit level gangways:
250s (medium propagation) to 360s (moderate
propagation)
Evacuation Time: [120s for discovery] +85 to
110s= 205 to 230s
Evacuation Validated
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Conclusions
SC-GS/PI
CFD and evacuation simulation tools allowed simulation
and reasoned validation of complex and non standard
geometries
The findings show that the gap between evacuation and
smoke propagation is not high
Several measures have to be in place in order to minimize
delays and difficulties in case of emergency
…(but this is by itself a different and huge subject)
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