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December 11th-12th, 2000 International Aircraft Systems Fire Protection Working Group

NEA Ullage Washing Testing With a Vented Fuel Tank. December 11th-12th, 2000 International Aircraft Systems Fire Protection Working Group. Outline. Background Ullage Washing Data Model Validation Hydrocarbon Effects Data Temperature Effects Data. Background.

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December 11th-12th, 2000 International Aircraft Systems Fire Protection Working Group

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  1. NEA Ullage Washing Testing With a Vented Fuel Tank December 11th-12th, 2000International Aircraft Systems FireProtection Working Group AAR-422 Fire Safety R&D

  2. Outline • Background • Ullage Washing Data • Model Validation • Hydrocarbon Effects Data • Temperature Effects Data AAR-422 Fire Safety R&D

  3. Background • Obtained Nitrogen Supply System from Air Liquide to Examine Fuel Tank Ullage Washing • Utilized Existing Test Article • Primary Task is to Characterize the Ability of Nitrogen to Inert an Empty Fuel Tank • Effective of Nitrogen Purity, Flow Rate • Effective Ullage Temperature / Hydrocarbon Concentration • Develop Empirical Relationships and Varify Existing Models AAR-422 Fire Safety R&D

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  6. Nondimensional Time • Want to Express Time in Terms of Volume Delivered • Volumetric Tank Exchange = Time * Volume Flow Rate / Total Tank Volume • Should Allow for Comparison of Data with Different Parameters, Regardless of Volume Flow Rate AAR-422 Fire Safety R&D

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  9. Nondimensional Oxygen Concentration • Want to Express [O2] in Terms of Purity Delivered. Consider that Gas is Slowly Changing the Ullage to Gas Purity • Tank Inertion Ratio = Air[O2] - Tank[O2] / Air[O2] - NEA[O2] • Should Allow for Comparison of Data with Different Parameters, Regardless of Purity AAR-422 Fire Safety R&D

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  11. Comparison of Data with Solutions • Empirical Equation (fourth order polynomial) Based on Previous Graph • ANM-100 Model (Ivor Thomas) • Based on O2 Volume Exchange • Gives One Nondimensional Solution • Exact Solution Based on Perfect Mixing Model (y = 1 - e-λt ) • Results Compare Well AAR-422 Fire Safety R&D

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  14. Effects of Ullage Temperature / [THC] • Performed Several Tests Varying Tank Ullage Temperature and Total Hydrocarbon Concentration • Used Hot Plate Element, Kerosene Heater, and Liquid CO2 • Final Results Show Little Effect on Time to Inert AAR-422 Fire Safety R&D

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  17. Future Work • Continue with Re-circulate and Replace Work and Quantify Benefit • Extrapolate Requirements for an On-Aircraft System and Determine Preliminary Cost/Ben • Work with Manufacturers to Develop Innovative Designs to Cut Cost/Weight/Size AAR-422 Fire Safety R&D

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