Modeling Smoke Transport in Aircraft Cargo Compartments
Jill Suo-Anttila‡, Stefan Domino†, Walt Gill‡, Paul DesJardin‡, and Lou Gritzo‡
‡Fire Science and Technology Department†Thermal/Fluids Computational Engineering Sciences Group
Sandia National LaboratoriesAlbuquerque, NM
David BlakeFire Safety Section
FAA Technical Center
International Aircraft Systems Fire Protection Working Group MeetingMarch 13, 2002
Modeling Smoke Transport in Aircraft Cargo Compartments
Goal: Develop a CFD-based simulation tool to predict smoke transport in cargo compartments
• Improve the certification process– Identify optimum smoke detector locations– Specify sensor alarm levels – Identify worst case fire locations– Reduce the number of flight tests
• Fast running • Suitable for non-expert users • Experimental data for source term
characterization from FAA experiments• Validated using FAA full-scale experiments
Built on firm FAA knowledge base
Validated using FAA experiments
Airlines, Air-Framers, Certifiers
Robust and fast running
Insight into Physical Processes
• FAA experiments helped identify four classes of cargo FAA experiments helped identify four classes of cargo compartment fire scenarioscompartment fire scenarios
• Model capable of assessing these scenarios (curvature Model capable of assessing these scenarios (curvature and packing issues addressed)and packing issues addressed)
Buoyant Plume Attached Flow
Diffuse Source Containerized
Smoke Transport Code Features• Curvature of compartment is resolved on
grid
• Arbitrary ventilation inlets and outlets can be specified
• Location and type of fire can be selected
• HRR, MLR are time varying inputs (as measured in FAA experiments)
• Species tracking: presently soot, CO, and CO2 but addition of more or different species possible
• Simulation time on the order of hours
• Validated using FAA full-scale experiments
computational computational grid cell on wallgrid cell on wall
cellmass VMS /
cellener VQS /
180 240120600
12
10
8
6
4
2
0
Con
cent
ratio
n C
O 2, C
O, H
Cl,
H2O
(p
arts
per
thou
sand
)
Time (seconds)
Concentration A
ll Other G
ases (parts per m
illion)120
100
80
60
40
20
0
CO2
CO
H20
HCl
HCNNOethylene
acteylenemethane
HCl
Smoke Transport Code Demonstration Calculations
Insert most recent movie of temperature distribution
• Buoyant Plume
– 300 sec flaming fire in the center of sealed compartment
– 300 sec flaming fire in sealed compartment with 45o offset gravity
– 300 sec flaming fire with ventilation
• Attached Flow
– 120 sec flaming fire near wall of sealed compartment
gravityinlet
outlet
Flaming Source Characterization
Insert most recent movie of temperature distributionFlaming Source - Mass Loss Rate
0.00E+00
5.00E-05
1.00E-04
1.50E-04
2.00E-04
2.50E-04
0 60 120 180 240 300
Time from Ignition (sec)
MLR
(kg/
sec)
Flaming Source - Heat Release Rate
0
1000
2000
3000
4000
5000
6000
0 60 120 180 240 300
Time from Ignition (sec)
HRR
(J/s
ec)
Flaming Source - Species
0
0.2
0.4
0.6
0.8
1
0 60 120 180 240 300
Time from Ignition (sec)
Mas
s Fr
actio
n (k
g/kg
)
Soot (kg/kg)
CO2 (kg/kg)
CO (kg/kg)
Smoke Transport Code Demonstration CalculationBuoyant Plume
• Flaming fire in the center
• 300 second simulation
• No specified ventilation
• Species concentrations (CO, CO2, soot) - aids in sensor selection and placement
gravity
Smoke Transport Code Demonstration CalculationBuoyant Plume with Varied Orientation
• Flaming fire in center
• Orientation of cargo bay 45o (y, +x gravity)
• 300 second simulation
• No specified ventilation
45o gravity
Smoke Transport Code Demonstration CalculationBuoyant Plume with Ventilation
• Flaming fire in center
• 0.5 m/s inlet in lower forward corner, outlet in upper aft
• 300 second simulation
gravityinlet
outlet
Smoke Transport Code Demonstration CalculationsBuoyant Plume Comparisons
Buoyant Plume
Ventilation Gravity
Smoke Transport Code Demonstration Calculation
• 120 second simulation (~9 hours of compute time for 10K grid points; Sun Ultra2).
• No specified ventilation
• HRR, MLR are time varying as measured in FAA experiments
• Species concentrations (CO, CO2, soot) - aids in sensor selection and placement
Soot Concentration
Temperature CO/CO2
• Plan developed by the FAA and SNL to verify and validate the smoke transport code
• Verification and validation of the code using:– Method of manufactured solutions– FAA full-scale experiments
• Verification using method of manufactured solutions complete• Baseline validation experiments to begin shortly
Model Verification and Validation
Following validation of the smoke transport code:
• Release of alpha version• Selection of approach for user interface • Develop and implement user interface• Documentation and release of code to small user community• Revisions and final release of code
Potential Future Activities
