TRANSPORT AND DISPERSION OF FIRE EXTINGUISHING AGENTS DOWNSTREAM FROM CLUTTER ELEMENTS OF AIRCRAFT ENGINE NACELLES By Khaled Zbeeb A Thesis Submitted to the Faculty of The College of Engineering and Computer Science in Partial Fulfillment of the Requirements for the Degree of Master of Science Florida Atlantic University Boca Raton, Florida April 2009 ACKNOWLEDGEMENTS I would like to thank Dr. Chaouki Ghenai for his hard work and support in developing the needed resources for this thesis. Also, I would like to express my gratitude to Dr. W. Bober and Dr. D. Moslemian for their advice and contribution. I would like to thank the people who helped me reviewing this thesis. iii ABSTRACT Author: Khaled Zbeeb Title: Transport and Dispersion of Fire Extinguishing Agents Downstream From Clutter Elements of Aircraft Engine Nacelles Institution: Florida Atlantic University Dissertation Advisor: Dr. Chaouki Ghenai Degree: Master of Science Year: 2009 The combination of highly turbulent airflow, flammable fluids, and numerous ignition sources makes aircraft engine nacelles a difficult fire zone to protect. Better understanding of nacelle air flow and how it influences the spread of fires and fire extinguishing agents is needed to improve the efficiency of fire suppression. The first objective was to establish a CFD model for a flow field test section to analyze the transport and dispersion of fire extinguishing agents in the presence of various clutter elements. To validate the use of the CFD model, the simulation results of the CFD model were compared to the experimental data and they show an agreement with the experimental data. The second objective was to present parametric studies to show the effects of the coflow speed, turbulence intensity and agent droplet size on the transport and dispersion of the agent particles downstream from the clutter elements. iv TRANSPORT AND DISPERSION OF FIRE EXTINGUISHING AGENTS DOWNSTREAM FROM CLUTTER ELEMENTS OF AIRCRAFT ENGINE NACELLES LIST OF FIGURES................................................................................................... viii LIST OF TABLES ....................................................................................................... x 1. INTRODUCTION.................................................................................................... 1 1.1 Engine Nacelles Fire Extinguishing Agents ............................................................ 1 1.2 Understanding the Whole Fire Suppression Challenge............................................ 5 1.3 Nomenclature....................................................................................................... 10 1.4 Test Section and Clutter Package.......................................................................... 11 2. GOVERNING EQUATIONS................................................................................. 14 2.1 Continuity and Momentum Equations................................................................... 14 2.2 Continuous Phase Modeling ................................................................................. 16 2.3 Turbulent Flow Equations .................................................................................... 16 2.4 Discrete Phase Modeling ...................................................................................... 18 2.5 Turbulence Dispersion of Particles ....................................................................... 19 2.6 Coupling between the Discrete and Continuous Phases......................................... 19 3. NUMERICAL METHODS .................................................................................... 21 3.1 CFD Numerical Methods................................................................................. 21 3.2 Numerical Methods using Fluent ..................................................................... 24 4. VALIDATION OF THE CFD MODEL RESULTS................................................ 34 v 4.1 Experimental Results............................................................................................ 34 4.2 CFD Simulation Results ....................................................................................... 39 4.3 Validation of the CFD Simulation Results ............................................................ 43 5. FLOW SIMULATION STUDY ............................................................................. 48 5.1 Coflow Speed Effects on Agent Particles Behavior............................................... 48 5.2 Turbulence Intensity Effects on Agent Particles Behavior..................................... 51 5.3 Injected Droplet Size Effects on Agent Particles Behavior.................................... 54 6. CONCLUSION...................................................................................................... 60 6.1 CFD Model Verification....................................................................................... 60 6.2 Flow Simulation Study......................................................................................... 60 6.3 Future Work......................................................................................................... 62 7. APPENDIX............................................................................................................ 64 7.1 Phase Doppler Anemometry System (Experiment) ............................................... 64 7.2 Experimental Strategy .......................................................................................... 64 7.3 Experimental General Strategy ............................................................................. 65 7.4 Experimental Data Analysis Strategy.................................................................... 66 7.5 Suppressant Transport Experimental Results and Discussion................................ 67 BIBLIOGRAPHY...................................................................................................... 72 vi LIST OF FIGURES Fig. 1.2.1 (PhostrEx Agent Flame Poisoning Chemistry [11]).......................................7 Fig. 1.2.2 (Front view of the test Section where new fire agents were tested on the F-15 engine nacelle[12])...............................................................................8 Fig. 1.2.3 (Side view of the test Section where new fire agents were tested on the F-15 engine nacelle[12])...............................................................................9 Fig. 1.2.4 (Back view of the test Section where new fire agents were tested on the F-15 engine nacelle[12]).............................................................................10 Fig. 1.4.1 (Test Section and Clutter Package)..............................................................12 Fig. 1.4.2 (3D view of the Test section and clutter package) .......................................12 Fig. 1.4.3 (Top view of the Test section and clutter package)......................................13 Fig. 3.1.1 (HTF7000 Nacelle Ventilation Design Intent [13])......................................21 Fig. 3.1.2 (Surfaces modeled (pylon side) and the nozzle surfaces used for injection of Halon 1301 into the nacelle [13]) ...........................................................22 Fig. 3.1.3 (Comparison of Halon concentrations between CFD and test Data for Probe1 [13])...............................................................................................23 Fig. 3.2.1 (3D View of the mesh created for the test section) ......................................31 Fig. 3.2.2 (Side view of the mesh created for the test section) .....................................31 Fig. 3.2.3 (Side view schematic of SF2 test section) ....................................................31 Fig. 4.1.1 ((SF)2 Zone A Test Section)[4]....................................................................34 vii Fig. 4.1.2 (U Velocity Data at 2.0 D Downstream for Various UC, CS)[4] ..................35 Fig. 4.1.3 (V Velocity Data at 2.0 D Downstream for Various UC, CS)[4] ..................35 Fig. 4.1.4 (Sauter Diameter Data at 2.0 D Downstream for Various UC, CS)[4] ..........36 Fig. 4.1.5 (U Velocity Data at 5.5 D Downstream for Various UC, CS)[4] ..................36 Fig. 4.1.6 (V Velocity Data at 5.5 D Downstream for Various UC, CS)[4] ..................37 Fig. 4.1.7 (Sauter Diameter Data at 5.5 D Downstream for Various UC, CS)[4] ..........37 Fig. 4.2.1 (Particle Traces colord by Particle X-Velocity (m/s)) ..................................38 Fig. 4.2.2 (Particle Traces colord by Particle Y-Velocity (m/s)) ..................................39 Fig. 4.2.3 (Particle Traces colord by Particle Z-Velocity (m/s)) ..................................39 Fig. 4.2.4 (Particle Traces colord by Particle Diameter (m))........................................40 Fig. 4.2.5 (3D Air X-Velocity Distribution along the Centerline (m/s)).......................40 Fig. 4.2.6 (Air X-Velocity Distribution At Z=0 (Centerline) (ms/s)) ...........................41 Fig. 4.2.7 (Air X-velocity Distribution at 2D Downstream the Clutter (m/s)) ..............41 Fig. 4.3.1 (Droplet X-Velocity Comparison 2D Downstream the Clutter) ...................43 Fig. 4.3.2 (Droplet Y-Velocity Comparison 2D Downstream the Clutter) ...................44 Fig. 4.3.3 (Droplet Diameter Comparison 2D Downstream the Clutter) ......................45 Fig. 4.3.4 (Percentage Error of the Droplet Results by using Fluent)...........................46 Fig. 5.1.1 (Comparison of Particle Traces Colored by Particle X-velocity