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Scale Model Inerting Testing ___________________________________ AAR-422 Fire Safety R&D July 17-18, 2001 International Aircraft Systems Fire Protection Working Group Wilson, NC Scale Model InertingTesting with 1/4 Scale Boeing 747 SP Fuel Tank
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Scale Model Inerting Testing ___________________________________ AAR-422 Fire Safety R&D Background Inconsistent Comparisons of Test Data Created Questions of NEA Required to Inert an Aircraft Center Wing Tank Focus of the Testing is to Better Determine the Best Method to Inert a Compartmentalized Fuel Tank Study Equal NEA Distribution and Localized NEA Deposit Study Cross-Vented and Single Vent Configurations Develop Methods to Make Fair Comparisons.
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Scale Model Inerting Testing ___________________________________ AAR-422 Fire Safety R&D Test Article Quarter Scale Model of Boeing 747 SP CWT was Built from Plywood By Scaling Drawings from Shepherd Report –24% length Scale (1.2% Volume) –Scaled all Bay-Bay Penetrations “Variable Manifold” Allows for Depositing NEA in Any and All Bays of the Tank at Different Rates to Support Inerting Times as Low as 10 Minutes Oxygen Sensor in Each Bay and in One Vent Channel
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Scale Model Inerting Testing ___________________________________ AAR-422 Fire Safety R&D Scale Model Bay Convention Dry Bay 1 2 34 56
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Scale Model Inerting Testing ___________________________________ AAR-422 Fire Safety R&D Preliminary Balanced Data Inerted Tank Several Times with NEA 95% and NEA 98% with the Goal of Balancing the Flow into Inert Each Bay “Equally” for Standard Cross-Venting Configuration Acquired Data with a Stop Watch (1 reading per minute) Developed a Volumetric Average to Make Comparisons with Other Inerting Runs Results As Expected and Consistent with Previous Testing but New Numbers Point Toward a VTE of 1.6 for 95% NEA –VTE Very Sensitive to O 2 Concentration at 8% for 95% NEA
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Scale Model Inerting Testing ___________________________________ AAR-422 Fire Safety R&D Preliminary Balanced Inerting Data
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Scale Model Inerting Testing ___________________________________ AAR-422 Fire Safety R&D Preliminary Balanced Weighted Average Data
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Scale Model Inerting Testing ___________________________________ AAR-422 Fire Safety R&D Preliminary Unbalanced Data Inerted Tank Several Times with NEA 95% with the Goal of Minimizing the Volume Required to Inert the Tank with Standard Cross-Venting Configuration Acquired Data with a Stop Watch (1 reading per minute) Used the Volumetric Average Developed to Make Fair Comparisons with Other Inerting Runs Results Illustrated Very Little Improvement in VTE Required, but Allowed for Simpler Manifold Designs –Smart Design as Good or Better then Well Balanced Manifold
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Scale Model Inerting Testing ___________________________________ AAR-422 Fire Safety R&D Preliminary Unbalanced Inerting Data
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Scale Model Inerting Testing ___________________________________ AAR-422 Fire Safety R&D Preliminary Unbalanced Weighted Average Data
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Scale Model Inerting Testing ___________________________________ AAR-422 Fire Safety R&D NEA Minimization Data Inerted Tank Several Times with NEA 95% to Minimizing the NEA Volume Required to Inert the Tank with Half Vent System Blocked (No Cross Venting) Acquired Data with Computer Data Acquisition System at a Rate of 1 Sample per Second (Approximate) First did Balanced Run to Give Baseline; Used the Volumetric Average Developed to Make Fair Comparisons with Other Inerting Methods Results Illustrated Modest Improvement with Simplest Deposit Scheme
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Scale Model Inerting Testing ___________________________________ AAR-422 Fire Safety R&D NEA Minimization Data - Best Data
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Scale Model Inerting Testing ___________________________________ AAR-422 Fire Safety R&D Unbalanced Weighted Average Data
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Scale Model Inerting Testing ___________________________________ AAR-422 Fire Safety R&D Summary Model Results Consistent with Existing Knowledge Base But VTE Slightly Higher in These Experiments –This is Believed to be due to Better Measurement Techniques Developed Depositing in an Efficient Manner Can Greatly Simplify Manifold Design and Even Improve Inerting Efficiency Still Need to Verify Results in Full-Scale Test Article
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