1	Fire Suppression Modeling Applied to Shipboard Design Session 3
2	Introduction Purpose of fire suppression modeling Assist in optimizing the suppression design Eliminate unsuitable suppression design prior to testing Reduce the number of tests required to validate suppression design Goals of fire suppression modeling: Predict shipboard compartment temperature conditions Predict suppression impact on fire
3	Fire Suppression System Model FDS – Fire Dynamics Simulator Version 3.0 Resolution of fluid flows expected to provide suppression system insight CFD model developed by NIST for low speed, thermally driven fluid flow Large Eddy Simulation method Simulates water droplet trajectories, evaporation, and radiation attenuation Droplets transfer momentum to space
4	Methodology Validate that FDS can predict the compartment temperature when fire is not suppressed Validate that FDS can simulate a water mist system Validate that FDS can predict the compartment temperature when fire is suppressed with mist
5	Other Research Results FDS has been compared with test data involving sprinkler systems [McGrattan et al., NISTIR 6196, 1998] 37-m by 37-m by 15-m test space Heptane spray fire nominally 4 – 6 MW FDS found to predict the number of sprinklers actuated and the compartment temperature FDS was not able to predict when the fire was extinguished by sprinklers
6	NISTIR Sprinkler Suppression Results
7	Compartment Fire Simulations – No Fire Suppression FDS validated using indirect cooling fire tests conducted in June, 02. [Luers et al., NRL Letter Report Serial 6180/0563, 2002] Space 25-ft by 34-ft by 11-ft high Single opening 7.5-ft by 6-ft tall Steel bulkhead and deck Heptane spray-pool fire
8	Results - Fire Simulations without Fire Suppression Average thermocouple tree data – measured versus calculated
9	Results – Fire Simulations without Fire Suppression
10	Mist Fire Suppression System Simulations – No Fire Nozzles: Nozzle A – High pressure (1,000-psi) Nozzle B – High pressure (1,000-psi) Nozzle C – Low pressure (150-psi) Key parameters: Drop mass distribution – Rossin-Rammler Operating pressure/K-factor Spray angle
11	Results (Mist Fire Suppression System Simulations – No Fire Nozzles tested in 30-ft by 30-ft by 9-ft space Drop distribution measured Conditions in space qualitatively assessed Mist transit time across room Spray distance Mist-air flow pattern
12	Results (Mist Fire Suppression System Simulations – No Fire)
13	Results (Mist Fire Suppression System Simulations – No Fire)
14	Mist Fire Suppression System - Modeling Validation Indirect cooling fire tests using a water mist fire suppression system conducted 6/02 [Luers et al., NRL Letter Report Serial 6180/0563, 2002] Mist nozzles types included high and low pressure Nozzle location and number were varied Fire size and location was varied Ventilation configuration was constant for the tests used in this validation
15	FDS Simulation – Compartment Geometry
16	Indirect Cooling Fire Test Simulations – Results Compartment Temperature Predictions with Mist Fire Suppression System: Thermocouple Trees
17	Indirect Cooling Fire Test Simulations – Results Compartment Temperature Predictions with Mist Fire Suppression System: Average Temperature
18	Indirect Cooling Fire Test Simulations – Results Compartment Temperature Predictions with Mist Fire Suppression System: Upper Layer Temperature (18-inches Beneath OH Deck)
19	Indirect Cooling Fire Test Simulations – Results Calculated Mist Fire Suppression System Impact in Space – Transient Average Temperature
20	Indirect Cooling Fire Test Simulations – Results Calculated Suppression System Impact in Space – Transient Average Temperature
21	Indirect Cooling Fire Test Simulations – Fire Extinguishment Prediction
22	Conclusions Temperature calculations FDS predicted the compartment temperature well in some cases FDS did not predict the compartment temperature well in other cases FDS was fair at predicted the average temperature FDS bulkhead temperature predictions were in general agreement with test data
23	Conclusions Suppression System Impact on Fire FDS was not able to predict fire extinguishment or suppression Modifications to combustion model may be necessary