Ground Based Fuel Tank Inerting

1
An Overview of FAA Fuel Inerting Research
March 12th-13th, 2002International Systems Fire
Protection Working GroupSeattle, Washington
2
Vertical Mixing / Temperature Effects

• Quiescent Full-Scale Testing has Indicated that
  Inerting of the B-747 SP in the Optimal Deposit
  Method Developed with the Plywood Model can be
  Problematic
• Inerting Efficiency Different from Test to Test
• Measured Strong Vertical Effects in one Full
  Length Bay
• Bottom of Bay Lags Behind Top of Bay on Most
  Tests
• Complicated by the Fact that Sample System only
  Samples from Top
• Observed Stratification of Inert Gas at Least
  Once with No Temperature Variation Between the
  Inert Gas and the Ullage
• Developed Deposit Gas Heat Exchanger to Study
  Temperature Effects
• Developed Inerting Efficiency Coefficient to
  Compare Tests
• Back Calculate VTEs between 1.2 and 2.0 to reach
  8 O2 with 95

3
Full-Scale B-747 SP Inerting Data
4
Inerting Efficiency

• Due to Sample Lag Dont have a Good Picture of
  Inerting in the Tank During Test
• Sample Biased Due to Location of Sample Ports
• Know Beginning Point (20.9) and End Point After
  Run ACMs
• Want to Approximate the Progression of Tank
  Oxygen Concentration During the Testing
• Use Generic Inerting Equation to Develop
  Efficiency Factor K
• Solve for K and Redimensionalize to Get a Curve
  for Each Test Result
• Did Several Tests with Different Temperature NEA

5
Full-Scale B-747 SP Inerting Data
6
Ancillary Equipment Development

• Cross-Flow Reduction Device
• Wrote and Distributed RFQ to Qualified
  Contractors for Developing a Cross-Flow Reduction
  Device for a B-747 SP
• Three Phase Development to Optimize One of Three
  Proposed Concepts, then Design and Fabricate a
  Part for Kit Installation
• OBGI Deposit System
• FAA Developing a Method for Distributing the OBGI
  System Gas by Using Scale Plywood Tank Testing
• RFQ for Development and Prototype in mid March

7
Flammability Survey of B-747 SP

• Measured Heating and Flammability Parameters in
  CWT of Full-Scale Test Article During Typical
  Ground Operation with Low Fuel
• Inert Tank Before Each Ground Sit (During Test)
• Target Different Temperature Days (Relatively
  Constant Ambient Temperature) with Mild Weather
• Run ACMs for 3 Hours to Make Cabin Comfortable
• Thermocouples in Pack Bay, Ullage, and Fuel (and
  Sump) as well as On Walls, Floor, and Ceiling
• All Data Obtained on Cool and Warm Days
• Need Heat of Summer and Cold of Winter Data

8
B-747 SP Flammability Data