Transcript A CFD METHODOLOGY FOR FIRE SPREAD AND RADIATIVE EFFECTS SIMULATION IN LONGITUDINAL VENTILATION TUNNELS: APPLICATION TO THE MEMORIAL TUNNEL D.

A CFD METHODOLOGY FOR FIRE SPREAD
AND RADIATIVE EFFECTS SIMULATION IN
LONGITUDINAL VENTILATION TUNNELS:
APPLICATION TO THE MEMORIAL TUNNEL
D. Borello*, G.Giuli** and F. Rispoli*
*DepartMent of Mechanics and Aeronautics University of Rome ‘La Sapienza’
**ENEA – Italian Agency for the Energy, the New Technologies and the
Environment
International PHOENICS User Conference – 23-27 September, 2002 – Moscow
INDEX
• MOTIVATIONS
• MEMORIAL TUNNEL DESCRIPTION
• FLOW MODELS
• NUMERICAL DETAILS
• NUMERICAL CAMPAIGN
International PHOENICS User Conference – 23-27 September, 2002 – Moscow
MOTIVATIONS
• MAJOR INTEREST IN TUNNEL SAFETY AND POLLUTION CONTROL
• EXPERIMENTAL RESULTS GIVE PARTIAL FLOW INFORMATION
• DEVELOPING A NUMERICAL METHODOLOGY DEVOTED TO
TUNNEL FLOW SIMULATION ABLE TO:
– PREDICT THE FLOW BEHAVIOR IN OPERATING CONDITIONS
– DESCRIBE THE FIRE SPREAD IN ORDER TO:
• PREDICT MAIN FLOW PHENOMENA
BACK-LAYERING AND SMOKE DIFFUSION
• DEFINE THE BEST VENTILATION CONFIGURATION IN
EMERGENCY SITUATIONS
International PHOENICS User Conference – 23-27 September, 2002 – Moscow
MEMORIAL TUNNEL 1/5
Memorial Tunnel Fire Ventilation Program
Massachusetts Highway Department & Bechtel/Parsons
Brinckerhoff, Massachusetts, November 1995
• EXPERIMENTAL CAMPAIGN (1995)
– LONGITUDINAL, TRANSVERSAL, MIXED CONFIGURATIONS
– LONGITUDINAL CONFIGURATION :
15
JET FANS
(in groups of three)
– LENGTH: 853 m, PASSAGE SECTION: 60.4 m2, SLOPE: 3.2 %
– JET FAN:
air velocity: 34.2 m/s, mass flow rate: 43 m3/s
International PHOENICS User Conference – 23-27 September, 2002 – Moscow
MEMORIAL TUNNEL 2/5
• SECTIONS
sect. B
sect. A
NORTH
ROOM
SOUTH
ROOM
811 m
7.86m
y
z
21.3m
4.33 m
sect. B
sect. A
853,7 m
8.76 m
Sect. A
y
7.86m
x
4.33 m
0.91 m
Walkway
Sect. B
0.76 m
0.91 m
8.76 m
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MEMORIAL TUNNEL 3/5
• PLANT
0m
I
N
L
E
T
x
z
95
N
1
o
2
r
t
3
h ON
190 285 379
4
7
474
10
13
5
8
11
14
6
ON
9
12
15
615
Pan
853.7 m
S
o
u
t
h
O
U
T
L
E
T
Jet Fans Flow
Slope 3,2 %
International PHOENICS User Conference – 23-27 September, 2002 – Moscow
MEMORIAL TUNNEL 4/4
• PANS
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MEMORIAL TUNNEL 5/5
• JET FANS
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FLOW MODELS
• 3-DIMENSIONAL, STEADY, TURBULENT REACTING FLOW
• TURBULENCE MODELING
– STANDARD k-e MODEL (Jones and Launder, 1988)
• BUOYANCY MODELING
• COMBUSTION MODELING
– HEAT SOURCE PLACED IN THE FIRE LOCATION
• RADIATION MODELING
– IMMERSOL SYNTHETIC TREATMENT (Spalding, 1991)
– NO RADIATION MODELING (Pucher et al., 2001)
International PHOENICS User Conference – 23-27 September, 2002 – Moscow
NUMERICS
1/2
• COMPUTATIONAL GRID: 31 X 30 X 327 cells
R = 4.33 m
2.44 m
R = 2.1 m
3.48 m
1.575 m
y
x
Walkway
8.76 m
International PHOENICS User Conference – 23-27 September, 2002 – Moscow
NUMERICS
2/2
• BFC GRIDS
• GENERALISED CO-LOCATED SCHEME
• SIMPLE SOLUTION SCHEME
• FALSE TIME STEP RELAXATION FOR V and T
• WALL ROUGHNESS : 3 mm
International PHOENICS User Conference – 23-27 September, 2002 – Moscow
ANALYSED TEST CASES
• COLD FLOW TEST: (T-A)
– 15 JET FANS
• T606A FIRE TEST (10 MW): (T-B, T-C)
–
2 JET FANS
International PHOENICS User Conference – 23-27 September, 2002 – Moscow
NUMERICAL CAMPAIGN
1/10
COLD FLOW SIMULATION
• OPERATING CONDITIONS:
– 15 ACTIVE FANS
– SWIRL NUMBER: 0.5
– CONSTANT PROPERTIES GAS
– WALL LAW FOR VELOCITY INSIDE THE TUNNEL
– FREE BOUNDARY CONDITIONS IN INLET AND OUTLET
• COMPARISONS
TEST
VENTILA
TION
JET
FANS
M. FLOW
Kg/s
ERROR
Exp
Longitud.
15
498.5
-
T-A
Longitud.
15
556.5
10.4 %
International PHOENICS User Conference – 23-27 September, 2002 – Moscow
NUMERICAL CAMPAIGN
2/10
FIRE SIMULATION
• TEST CASE T606A 10 MW
• OPERATING CONDITIONS:
– 2 ACTIVE FANS
– SWIRL NUMBER: 0.5
– IDEAL GAS
– WALL LAW FOR VELOCITY AND TEMPERATURE
– FREE BOUNDARY CONDITIONS IN INLET AND OUTLET
• SYNTHETIC AND DIRECT RADIATION SIMULATION
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NUMERICAL CAMPAIGN
3/10
FIRE SIMULATION
• CRITICAL VELOCITY: 1.8 m/s
(104 m3/s)
• COMPARISONS
Total Heat
Mass Flow
Jet Ventila Radiat.
Error
Rate
Rate
TEST
Model
Fan
tion
%
(MW)
(kg/s)
Exp
9.10
2
Long.
-
163
-
T-B
6.36
2
Long.
No
147.2
-9.8
T-C
9.10
2
Long.
Yes
137.2
-15.8
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NUMERICAL CAMPAIGN
4/10
FIRE SIMULATION
• COMPARISONS ( V and T PROFILES)
– MEASUREMENT POSITIONS
LOOP NAME
DISTANCE from
NORTH PORTAL
L214
18 m
L209
321 m
L305
604 m
L302
681 m
L202
833 m
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NUMERICAL CAMPAIGN
5/10
FIRE SIMULATION
• COMPARISONS ( T and V PROFILES)
L214 (18 m)
Pan
a)
b)
V (m/s)
T (°C)
Loop 214 – Temperature (a)
and
velocity (b)
profiles
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NUMERICAL CAMPAIGN
6/10
FIRE SIMULATION
• COMPARISONS ( T and V PROFILES)
L209 (321 m)
Pan
a)
b)
T (°C)
V (m/s)
Loop 209 – Temperature (a)
and
velocity (b)
profiles
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NUMERICAL CAMPAIGN
7/10
FIRE SIMULATION
• COMPARISONS ( T and V PROFILES)
L305 (604 m)
Pan
a)
b)
T (°C)
Loop 305 – Temperature (a)
V (m/s)
and
velocity (b)
profiles
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NUMERICAL CAMPAIGN
8/10
FIRE SIMULATION
• COMPARISONS ( T and V PROFILES)
L302 (681 m)
Pan
a)
b)
V (m/s)
T (°C)
Loop 302 – Temperature (a)
and
velocity (b)
profiles
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NUMERICAL CAMPAIGN
9/10
FIRE SIMULATION
• COMPARISONS ( T and V PROFILES)
L202 (833 m)
Pan
a)
b)
V (m/s)
T (°C)
Loop 202 – Temperature (a)
and
velocity (b)
profiles
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NUMERICAL CAMPAIGN
10/10
FIRE SIMULATION
• T contours
TEMPERATURE
4
PANS
VECTOR
T
(°C)
V
(m/s)
3
25
47
69
91
113
135
157
179
201
223
245
267
290
312
,0
,4
,8
1,2
1,6
2,0
2,4
2,7
3,1
3,5
3,9
4,3
4,7
5,1
5,5
International PHOENICS User Conference – 23-27 September, 2002 – Moscow
CONCLUSIONS
•
AN ACCURATE METHODOLOGY FOR FIRE SIMULATION IN
TUNNELS HAS BEEN DESCRIBED
•
THE PREDICTION CAPABILITIES HAVE BEEN DEMONSTRATED
IN CRITICAL FLOW CONDITIONS
•
SUCCESSFUL SIMULATION OF RADIATION PHENOMENA
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24.10.2001
International PHOENICS User Conference – 23-27 September, 2002 – Moscow