School of Civil and Industrial Engineering
Department of Structural and Geotechnical Engineering
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
Candidate:
Tiziano Baroncelli
A.Y. 2013/2014
Rome, 21 May 2014
Advisor:
Prof. Eng. Franco Bontempi
Co-advisor:
Eng. Alessandra Lo Cane
TUNNEL
FIRE
SAFETY
1) Problem
CONCEPTUAL MAP
2) General framework
3) Specific aspects
4) Results
COMPREHENSION
OF FIRE
DYNAMICS
CASE
HISTORY
SPECIFIC
EVENT
(FREJUS
FIRE)
140
EVENTS
STATISTICS
FLOW
CHART OF
THE EVENT
NORMATIVE
ASPECTS
EUROPEAN
NORMS:
Directive
2004/54/EC
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
NUMERICAL
ASPECTS
ITALIAN
NORMS: D.Lgs
264/2006,
ANAS 2009
TUNNEL
CFD
MODELS
EXPLICIT
HGV FIRE
Candidate:
Tiziano Baroncelli
BENCHMARK
OF THE CODE
quantitative
RISK
ANALYSIS
A.Y.:
2013 - 2014
1
2A) FIRE
DYNAMICS
COMPREHENSION OF FIRE DYNAMICS
UNDERSTANDING FIRE DYNAMICS
CLASSIFICATION OF
THE CASE HISTORY
SPECIFIC EVENT:
FREJUS FIRE – 06/04
a1) Typology of tunnel
a2) Length of the tunnel
a3) Cause of ignition
a4) Number of victims
a5) Number of wounded persons
a6) Relevant structural damages
4)
2)
3)
5)
S TRUCTURAL
FATALITIES WOUNDED
LENGHT
D.
N°
0)
EVENT
1)
TYPOLOGY
6)
CAUS E
7)
COUNTRY
1
S. M artino
10/09/2007
R
2
137
YES
A
4.8 km
HF
Collision
ITA
2
Burnley
23/03/2007
R
3
3
NO
A
3.5 km
HF
Collision
AUS
3
Eidsvoll
26/10/2006
R
1
1
NO
B
1.2 km
HF
Collision
NOR
4
Viamala
16/09/2006
R
9
9
NO
C
0.7 km
HF
Collision
SWI
5
M auernried
25/12/2005
R
5
5
NO
D
0.3 km
HF
Collision
GER
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
2
NORMATIVE
ASPECTS
NORMATIVE ASPECTS
Directive 2004/54/EC
CASE HISTORY OF
MAJOR TUNNEL FIRES
2B) NORMS
«on Minimun Requirements for all the Tunnel of the
Trans-European Road Network (TERN)»
executive
D. Lgs. 264/2006
1) DIRECTIVE 2004/54/EC about ‘minimum requirements for all the tunnels of the Trans-European Road
Network’ : gives a whole new approach in the tunnel fire safety, for as regards both new and existing tunnels.
-
Definition of MINIMUM REQUIREMENTS FOR ROAD TUNNELS LONGER THAN 500 m;
-
Introduction of the RISK ANALYSIS as an instrument for RISK ASSESSEMENT and DECISION
MAKING; RISK ANALYSIS is explicitly required in tunnel projecting;
-
Definition of the SAFETY PARAMETERS of road tunnels that SHALL BE TAKEN INTO COUNT
EXPLICITLY IN THE RISK ANALYSIS (length of the tunnels, cross section, lanes, traffic etc).
2) D. Lgs. 264/2006: EXECUTIVE NORM for Italy of the previous Directive 2004/54.
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
3
BENCHMARK OF THE CALCULATION CODE
2C) NUMERICAL ASPECTS
NUMERICAL
ADVANCED METHODS
for the assessment of the
consequence of road
tunnel fires
ISO 13887 (‘Assessment and
verification of Mathematical
Fire Models’)
REFERENCES
NUREG 1824 (‘Validation of
Fire Models for nuclear power
plant applications
BENCHMARK OF THE
CODE: Fire Dynamics
Simulator (FDS), vers. 6.0
PHYSICAL ACCURACY
(representativeness of the
phenomenon)
CRITERIA
MATHEMATICAL
ACCURACY (absence of
large numerical errors)
PHYSICAL
ACCURACY
𝓧
ANALYTICAL TESTS (submodels)
SENSITIVITY TO PHISICAL PARAMETERS
𝓧
𝓧
CODE CHECKING
MATHEMATICAL
ACCURACY
NUMERICAL TESTS (DNS simulations)
INFLUENCE OF THE MESH (‘sensitivity analysis’)
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
4
BENCHMARK OF THE CALCULATION CODE
BENCHMARK OF THE
CODE: Fire Dynamics
Simulator (FDS), vers. 6.0
1) MODEL # 1
2C) NUMERICAL ASPECTS
IGNITION
a) GLOBAL LEVEL
b) INTERMEDIATE LEVEL
c) LOCAL LEVEL
3) MODEL # 2*
Mesh transformations
2) MODEL # 2
4) MODEL # 3
5) MODEL # 4
MAIN ASPECTS OF THE BENCHMARK:
1) A fine grid (namely about 25 cm) should be used to represent adequately the fire source;
2) The use of a fine grid increases significantly calculation times;
3) Possibility to represent the following phenomena:
IGNITION (surface, object)
FLASHOVER
PROPAGATION
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
INFLUENCE OF OXYGEN
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
5
ADVANCED NUMERICAL
METHODS:
Application to a REAL
TUNNEL
2C) REAL TUNNEL
ST. DEMETRIO
Eng. Luigi Carrarini
ANAS
ST. DEMETRIO
ROAD TUNNEL
(SICILY)
Risk Analysis
Quantitative Risk Analysis
(QRA)
GEOGRAPHY
GEOMETRY
SAFETY EQUIPMENTS
Cross section
Qualitative Risk Analysis
(Risk Matrix)
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
Mechanical ventilation
Safety infrastructures
Illumination
Parameters
CATANIA - SYRACUSE
TUNNEL MODELLING
Tunnel schedule
Safety/control systems
Candidate:
Tiziano Baroncelli
Systems for users’
information
A.Y.:
2013 - 2014
6
ADVANCED NUMERICAL
METHODS:
Application to a REAL
TUNNEL
Eng. Luigi Carrarini
ANAS
2C) REAL TUNNEL
ST. DEMETRIO
TUNNEL MODELLING
Tunnel schedule
ST. DEMETRIO
ROAD TUNNEL
(SICILY)
Risk Analysis
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
7
2C) REAL TUNNEL
HGV MODEL
ADVANCED NUMERICAL
METHODS:
Application to a REAL
TUNNEL
LARGE SCALE TESTS
CREATING A SCENARIO
VEHICLE MODEL
SCENARIO
VENTILATION
CONE CALORIMETER
VALIDATED MODELS
LARGE SCALE FIRE TESTS – RUNEHAMAR TESTS (2003)
5.5 ton
81% wood
19% plastic
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
8
2C) REAL TUNNEL
HGV MODEL
TUNNEL MODELLING
ADVANCED NUMERICAL
METHODS:
Application to a REAL
TUNNEL
ST. DEMETRIO
ROAD TUNNEL
(SICILY)
LARGE SCALE TESTS
VEHICLE MODEL
VENTILATION
CONE CALORIMETER
VALIDATED MODELS
VALIDATED MODELS FOR VEHICLES – BUILDING A SIMPLE MODEL
To model the real geometry of the pallets, a
mesh of about 1 cm or less would be required:
this is pratically impossible
SIMPLIFIED APPROACH: materials are
organized in layers
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
9
2C) REAL TUNNEL
HGV MODEL
TUNNEL MODELLING
ADVANCED NUMERICAL
METHODS:
Application to a REAL
TUNNEL
ST. DEMETRIO
ROAD TUNNEL
(SICILY)
LARGE SCALE TESTS
VEHICLE MODEL
VENTILATION
CONE CALORIMETER
VALIDATED MODELS
VALIDATED MODELS FOR VEHICLES – BUILDING A SIMPLE MODEL
To model the real geometry of the pallets, a
mesh of about 1 cm or less would be required:
this is pratically impossible
SIMPLIFIED APPROACH: materials are
organized in layers
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
10
2C) REAL TUNNEL
HGV MODEL
TUNNEL MODELLING
ADVANCED NUMERICAL
METHODS:
Application to a REAL
TUNNEL
LARGE SCALE TESTS
VEHICLE MODEL
ST. DEMETRIO
ROAD TUNNEL
(SICILY)
VENTILATION
OTHER MATERIALS
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
CONE CALORIMETER
VALIDATED MODELS
IGNITION SOURCE
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
11
2C) REAL TUNNEL
HGV MODEL
TUNNEL MODELLING
ADVANCED NUMERICAL
METHODS:
Application to a REAL
TUNNEL
LARGE SCALE TESTS
VEHICLE MODEL
ST. DEMETRIO
ROAD TUNNEL
(SICILY)
VENTILATION
OTHER MATERIALS
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
CONE CALORIMETER
VALIDATED MODELS
IGNITION SOURCE
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
12
2C) REAL TUNNEL
VENTILATION
TUNNEL MODELLING
ADVANCED NUMERICAL
METHODS:
Application to a REAL
TUNNEL
ST. DEMETRIO
ROAD TUNNEL
(SICILY)
VEHICLE MODEL
NATURAL VENTILATION
VENTILATION
MECHANICAL
VENTILATION
NATURAL
VENTILATION
ONLY FOR TUNNELS NO LOGER THAN 500 m
TRANSVERSE: often in BIDIRECTIONAL
TUNNELS (ONE TUBE)
MECHANICAL
VENTILATION
LONGITUDINAL: in MONODIRECTIONAL
TUNNELS (TWO TUBES) – «JET FANS
SYSTEMS»
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
13
2C) REAL TUNNEL
VENTILATION
TUNNEL MODELLING
ADVANCED NUMERICAL
METHODS:
Application to a REAL
TUNNEL
ST. DEMETRIO
ROAD TUNNEL
(SICILY)
VEHICLE MODEL
NATURAL VENTILATION
VENTILATION
MECHANICAL
VENTILATION
NATURAL
VENTILATION
ONLY FOR TUNNELS NO LOGER THAN 500 m
TRANSVERSE: often in BIDIRECTIONAL
TUNNELS (ONE TUBE)
𝓧
MECHANICAL
VENTILATION
LONGITUDINAL: in MONODIRECTIONAL
TUNNELS (TWO TUBES) – «JET FANS
SYSTEMS»
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
13
RESULTS OF THE ANALYSIS
RESULTS OF THE
ANALYSIS
HGV SIMULATIONS
RISK ANALYSIS
Scenario
Fire source
Distance from
the portal
Ventilation
Jet fans
Scenario
Fire source
Distance from
the portal
Ventilation
Jet fans
1
HGV
200 m
No
No
1
2 CARS
200 m
Yes (~ 3 m/s)
Yes
2
HGV
200 m
Yes (1 m/s)
No
2
BUS
200 m
Yes (~ 3 m/s)
Yes
3
HGV
200 m
Yes (2 m/s)
No
4
HGV
200 m
Yes (3 m/s)
No
5
HGV
200 m
Yes (~ 2 m/s)
Yes
The vehicles are not modelled explicitly, but using a specific
ramp (forced combustion at a specific rate).
RESULTS
Global level: SMOKE and FLAME DEVELOPMENT
(qualitative); FIELDS OF TEMPERATURES
Intermediate level: HRR and BURNING RATE
Local level: THERMOCOUPLES
RESULTS
Global level: SMOKE DEVELOPMENT (qualitative);
FIELDS OF TEMPERATURES
Local level: TEMPERATURES, CO, SOOT and
OXYGEN CONCENTRATIONS, VISIBILITY, FED
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
14
v = 2 m / s (uniform)
EXIT PORTAL (Syracuse)
+z
BY-PASS
300 m
ENTRANCE PORTAL (Catania)
BY-PASS
RESULTS OF THE ANALYSIS
9.5 Φ
27.3 Φ
36.8 Φ
HGV
TRAFFIC FLOW
195 m
2695 m
2595 m
2295 m
+z
105 m
9.5 Φ
45.9 Φ
2895 m
17.7 Φ
BACKLAYERING after 95 s
GLOBAL LEVEL RESULTS: 1) SMOKE DEVELOPMENT
+y
+Φ
66.7 Φ
TUNNEL FULFILLMENT after 239 s
t = 1 min
t = 2 min
t = 3 min
t = 4 min
t = 5 min
REACHED BY SMOKE after 208 s
REACHED BY SMOKE after 54 s
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
15
HGV / #3
v = 2 m / s (uniform)
EXIT PORTAL (Syracuse)
RESULTS OF THE ANALYSIS
+z
BY-PASS
BY-PASS
300 m
105 m
9.5 Φ
36.8 Φ
27.3 Φ
HGV
195 m
TRAFFIC FLOW
2695 m
2595 m
2295 m
2190 m
+z
ENTRANCE PORTAL (Catania)
9.5 Φ
45.9 Φ
+y
2895 m
17.7 Φ
+Φ
66.7 Φ
LOCAL LEVEL RESULTS: 1) THERMOCOUPLES
PERFORMANCE FIRE
BASED DESIGN
PRESCRIPTIVE FIRE
BASED DESIGN
FIRE SOURCE
Front
Mid1
Mid2
Back
NO DECAY
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
16
INTERMEDIATE LEVEL RESULTS: 1) SMOKE DEVELOPMENT
«FUEL – CONTROLLED» FIRES
UNLESS SEVERAL VEHICLES ARE INVOLVED IN THE FIRE, THE QUANTITY OF AIR IS MUCH
ENOUGH TO ALLOW THE COMPLETE COMBUSTION OF THE MATERIAL: THE VEHICLE
COMPARISON
BURNS AS IN OUTDOOR FIRES, WHERE THE VENTILATION DOESN’T INFLUENCE THE HEAT
RELEASE.
Scenario #2 – v = 1 m/s
Scenario #3 – v = 2 m/s
Scenario #1 – v = 0 m/s
CFD comparison test*
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
TIME SHIFT FOR
THE HRR CURVE
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
17
INTERMEDIATE LEVEL RESULTS: 1) SMOKE DEVELOPMENT
+z
«FUEL – CONTROLLED» FIRES
THE TIME SHIFT IS ASSOCIATED TO
-y
-x
THE DIFFERENT ORIENTATION OF
COMPARISON
THE IGNITION SOURCE IN THE
≠
COMPARED SIMULATIONS.
Scenario #1 – v = 0 m/s
CFD comparison test*
Scenario #2 – v = 1 m/s
Scenario #3 – v = 2 m/s
Scenario #1 – v = 0 m/s
CFD comparison test*
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
TIME SHIFT FOR
THE HRR CURVE
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
17
TUNNEL MODELLING
SIMPLIFIED APPROACH
FOR QUANTITATIVE RISK
ASSESSMENT
CRITERIA FOR
QUANTITATIVE
RISK ASSESSMENT
BURNING SURFACES
ON THE BASIS OF THE
EUREKA TESTS
WHICH ASPECTS OF
THE FIRE THREAT TO
USER’S LIFE?
2C) REAL TUNNEL
VENTILATION
HEAT
SMOKE
RADIATION
2 CARS FIRE
SIMPLIFIED
APPROACHES: based on
simple criteria about the
mentioned aspects
BUS FIRE
COMPLETE
APPROCHES: based on
toxicity criteria with all the
concentrations of toxic
gases and oxygen.
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
Candidate:
Tiziano Baroncelli
Carbon
dioxide
Carbon
monoxide
A.Y.:
2013 - 2014
Oxygen
18
v,emergency ~ 3 m / s (jet fans)
EXIT PORTAL (Syracuse)
RESULTS OF THE ANALYSIS
+z
BY-PASS
JET FAN
2190 m
2295 m
2375 m
+z
9.5 Φ
300 m
JET FAN
2525 m
28.6 Φ
BY-PASS
2595 m
38.1 Φ
JET FAN
100 m
BUS
ENTRANCE PORTAL (Catania)
TRAFFIC FLOW
200 m
2675 m 2695 m
9.5 Φ
47.6 Φ
2825 m
19 Φ
+y
2895 m
+Φ
66.7 Φ
GLOBAL LEVEL RESULTS: 1) SMOKE DEVELOPMENT – 2 CARS FIRE
t = 4 min
t = 6 min
t = 8 min
t = 10 min
t = 12 min
Controlled Backlayering
t = 14 min
REACHED BY SMOKE after 205 s
𝑉𝑚,2 = 1.92 m/s
REACHED BY SMOKE after 49 s 𝑉𝑚,1 = 2.04 m/s
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
19
v,emergency ~ 3 m / s (jet fans)
EXIT PORTAL (Syracuse)
RESULTS OF THE ANALYSIS
+z
BY-PASS
JET FAN
2190 m
2295 m
2375 m
+z
9.5 Φ
300 m
JET FAN
2525 m
28.6 Φ
BY-PASS
2595 m
38.1 Φ
JET FAN
100 m
ENTRANCE PORTAL (Catania)
BUS
TRAFFIC FLOW
200 m
2675 m 2695 m
9.5 Φ
47.6 Φ
2825 m
19 Φ
+y
2895 m
+Φ
66.7 Φ
GLOBAL LEVEL RESULTS: 1) SMOKE DEVELOPMENT – BUS FIRE
t = 2 min
t = 4 min
t = 6 min
t = 8 min
t = 10 min
Loss of stratification
REACHED BY SMOKE after 154 s
𝑉𝑚,2 = 2.59 m/s
REACHED BY SMOKE after 66 s 𝑉𝑚,1 = 1.51 m/s
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
20
CONCLUSIONS:
- Numerical advanced methods are assuming a crucial role in the Fire Safety
Engineering, with an increasing level of detailing and a fine reprodution of the
phenomenon; the main advantages are the deterministic description of the
CONCLUSIONI
consequences of a fire and the diffusion of validated models for vehicles, extremely
useful both in the Fire Structural Engineering and in the Risk Analysis, and the
possibility to assess different failure scenarios.
- The explicit model of a vehicle can catch very precise (local) aspects that can’t be
reproduced with a different approach;
- Some aspects are well catched by the model of the St. Demetrio Road tunnel
(growing phase, peak of HRR, first phase of decay), while others would need a
finer model, both for the grid and the vehicle;
- The criteria for the assessment of the risk give a very precise description of the
safety conditions inside a tunnel for escaping users.
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
21
THE END
Fig. 6.6 – Summary of the local results (thermocouple temperatures).
Fig. 6.7 – Temperatures above the fire source.
The local analysis of the temperatures (fig. 6.6 and 6.7) show that the temperature above
the fire source is good represented (unless the second phase of the decay mentioned
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
22
TURBULENCE MODELLING
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
23
TURBULENCE MODELLING
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
24
TURBULENCE MODELLING
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
25
TURBULENCE MODELLING
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
26
TURBULENCE MODELLING
“Computational Fluid Dynamics Simulations
for Risk Analysis of Fires in Road Tunnels”
Candidate:
Tiziano Baroncelli
A.Y.:
2013 - 2014
27