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 Laboratories Albuquerque, NM David Blake Fire Safety Section FAA Technical Center International Aircraft Systems Fire Protection Working Group Meeting March 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 compartment fire scenariosFAA experiments helped identify four classes of cargo compartment fire scenarios Model capable of assessing these scenarios (curvature and packing issues addressed)Model capable of assessing these scenarios (curvature 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 CO 2 but addition of more or different species possible Simulation time on the order of hours Validated using FAA full-scale experiments computational grid cell on wall

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 45 o offset gravity –300 sec flaming fire with ventilation Attached Flow –120 sec flaming fire near wall of sealed compartment gravity inlet outlet

Flaming Source Characterization Insert most recent movie of temperature distribution

Smoke Transport Code Demonstration Calculation Buoyant Plume Flaming fire in the center 300 second simulation No specified ventilation Species concentrations (CO, CO 2, soot) - aids in sensor selection and placement gravity

Smoke Transport Code Demonstration Calculation Buoyant Plume with Varied Orientation Flaming fire in center Orientation of cargo bay 45 o (y, +x gravity) 300 second simulation No specified ventilation 45 o gravity

Smoke Transport Code Demonstration Calculation Buoyant Plume with Ventilation Flaming fire in center 0.5 m/s inlet in lower forward corner, outlet in upper aft 300 second simulation gravity inlet outlet

Smoke Transport Code Demonstration Calculations Buoyant Plume Comparisons Buoyant Plume Ventilation Gravity

Smoke Transport Code Demonstration Calculation 120 second simulation (~9 hours of compute time for 10K grid points; Sun Ultra 2 ). No specified ventilation HRR, MLR are time varying as measured in FAA experiments Species concentrations (CO, CO 2, 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