Engine Nacelle Halon Replacement, FAA, WJ Hughes Technical Center - PowerPoint PPT Presentation

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Engine Nacelle Halon Replacement, FAA, WJ Hughes Technical Center

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1 thermocouple mounted on door exterior, sta 514, 11:30 ... summed all areas for thermocouples affected by fire (sta's 510, 514, 518, 532, 551) ... – PowerPoint PPT presentation

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Title: Engine Nacelle Halon Replacement, FAA, WJ Hughes Technical Center


1
Engine Nacelle Halon Replacement,FAA, WJ Hughes
Technical Center
  • Point of Contact Doug Ingerson
  • Department of Transportation
  • Federal Aviation Administration
  • WJ Hughes Technical Center
  • Fire Safety Branch, AAR-440
  • Bldg 205
  • Atlantic City Int'l Airport, NJ 08405 USA
  • tel 609-485-4945
  • fax 609-485-7074
  • email Douglas.A.Ingerson_at_faa.gov
  • web page http//www.fire.tc.faa.gov/

2
  • Major Topics for Review
  • brief overview
  • revision to minimum performance standard for
    engine/apu (mpse)
  • foundation test plans and results
  • near term plans

3
  • BRIEF OVERVIEW
  • April - July 2002, Testing
  • Encountered difficulty with hot surface ignition
    (HSI) during initial MPSE tests
  • Ran series of tests and observed HSI behavior -
    determined phenomena is unreliable
  • Reviewed a sample of reported HSI behaviors
  • Results indicated current version of the MPSE was
    faulted by HSI unreliability
  • Ran 100 plus tests to find a way to circumvent
    HSI unreliability
  • 23 24 July 2002, Task Group Meeting
  • Convened and discussed issues involving MPSE and
    HSI
  • Agreed MPSE required revision
  • Conceived method to track Halon 1301 suppression
    performance using HSI reliably
  • Formulated rough revision of MPSE (revision 3)
  • Planned foundation testing to resolve potentially
    complicating issues
  • August 2002 - Present
  • Produced a crude flowchart of MPSE revision 3
  • Partially completed the foundation testing

4
  • REVISION OF THE MPSE
  • Evaluating the Basis for the Agent Comparison in
    the MPSE
  • MPSE process will have error in results due to
    environmental behaviors observed to date -
    conservatism is required, yet error must be
    minimized where possible
  • Experienced/reported difficulty with reliable HSI
    behavior would lead to greater expected error in
    final results
  • Equivalence method must represent the associated
    application in a reliable manner
  • Equivalence method relies on the occurrence of
    HSI as it is a threat in this application
  • Testing during
  • April - June 2002 the continually operating
    electrodes (COE) or a tube array of particular
    geometry reliably reignited JP-8
  • June - July 2002 primary ignition difficulty
    with low volatility fuel (oil) in the spray fire
    scenario - suspected impact on HSI behavior using
    the COE alone
  • July - August 2002 a combination of the COE and
    the tube array provided reliable HSI behavior for
    any fuel type evaluated

5
  • REVISION OF THE MPSE
  • The Significant Change to the MPSE
  • Former version of the MPSE
  • reliance upon the definition of a robust fire
  • equivalence process required finding a minimum of
    3 robust fires
  • the robust fire was a mixture of test conditions
    that would be extinguished by Halon 1301 for a
    portion of a fixed number of duplicate tests
    (80-90)
  • a successful quantity of the replacement
    candidate was to repeat Halon 1301 behavior
    against the same conditions
  • HSI in this geometry is an imprecise behavior and
    was buried in the robust fire
  • Version 3 of the MPSE
  • robust fire eliminated
  • changed performance measure to Reignition Time
    Delay - the time between fire extinguishment and
    reignition which is based on a video review of
    the test
  • Reignition Time Delay (RTD) is based on a
    minimum of 5 tests at like condition
  • a successful quantity of a replacement candidate
    will be required to repeat or exceed the RTD for
    Halon 1301 at the same test conditions
  • HSI is provided for with intentional secondary
    ignition sources

6
  • REVISION OF THE MPSE
  • Items of Concern for MPSE revision 3
  • Concerns are included for consideration in MPSE
    revision 3 to improve on the body of work to date
  • Concerns are reasoned as impacts on the
    credibility of the final results
  • compartment ventilation conditions
  • agent storage, release, and distribution
  • sufficient severity of the fire threat
  • variation in the RTD must be observed and
    understood
  • Concerns will be addressed with foundation
    testing and review of others work
  • Retain portions of previous MPSE revision to
    minimize loss of time

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8
  • REVISION OF THE MPSE
  • Spray Fire Zone Configuration, MPSE revision 3

ELECTRODES
CORE
TUBE ARRAY
FUEL NOZZLES
2 TALL FLAME STABILIZATION RIB
sta 502
sta 510
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12
  • REVISION OF THE MPSE
  • Process Overview
  • Parameter for comparing agent suppression
    performances is RTD not robust fire
  • RTD is the duration of time between fire
    extinguishment and reignition
  • RTD requires a test fixture which includes
    RELIABLE secondary ignition sources
  • Primarily, a single RTD will represent a group
    of duplicate agent suppression tests
  • Basis for success RTD Halon 1301 ? RTD
    Candidate replacement
  • Testing will account for representative
  • ventilation conditions
  • agent storage and discharge considerations
  • fuels types in a nacelle/APU
  • fire scenarios
  • Process will allow for rational test planning
  • test against the most challenging condition(s)
  • run verification tests against conditions not
    explicitly evaluated
  • attempting to separate fire suppression and agent
    distribution performances

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14
  • FOUNDATION TESTING
  • Test Results - Purpose and General Comments
  • Testing to
  • answer questions conceived during initial
    discussions of MPSE revision 3
  • provide data to observe behaviors and uncover
    issues not initially recognized
  • Focused on previously stated concerns
  • List of issues to be addressed by this testing
  • verify the fire threats are sufficiently severe
  • minimize/understand varying RTD behavior
  • fuel type - observe/compare combustion behaviors
  • agent discharge - consistent preburn or tube
    array temperature
  • material changes in the tube array - determine
    its life span
  • explore residual fire scenario - determine
  • which fuel types can burn in this configuration
  • the significance of HSI phenomena
  • the effect of the orientation of the pan geometry
    on fire intensity

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17
  • FOUNDATION TESTING
  • Test Results (continued) - Varying RTD/Decision
    to Release Agent
  • Run a series of spray fire tests and evaluate
    resulting RTDs
  • Purposes
  • determine if RTD variation can be better
    controlled by releasing the agent after
  • a consistent preburn duration expires
  • a consistent temperature in the tube array is
    attained
  • use results to refine MPSE version 3
  • Current test procedure relies on preburn duration
  • Control of the test article changed for the
    trials involving tube array temperature
  • Conditions
  • air flow ? 2.2 lbm/s _at_ 100F
  • JP-8 ? 0.25 gpm
  • agent ? HFC-125 _at_ 5.2 lbm
  • Fixed preburn duration ? 45 seconds
  • Fixed tube array temperature ? 1440F

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19
  • FOUNDATION TESTING
  • Test Results (continued) - Varying RTD/Fuel-Spray
    Fire Intensity
  • Ran spray fire tests and recorded temperature
    profiles
  • Purposes
  • observe fire behaviors
  • compare energy signature for each fuel
    type/ventilation condition
  • use data in refining MPSE revision 3
  • Thermocouples spaced longitudinally in the flame
    path to provide representative picture of
    combustion behavior
  • Each individual test condition was repeated 3
    times
  • Fixture cooled down to near ambient condition
    between tests
  • Test conditions
  • fuels JP-8, oil (Mobil Jet Oil II), hydraulic
    fluid (Skydrol LD-4)
  • fuel flow rates 0.25 gpm /- 0.03gpm
  • ventilation conditions 2.2 lbm/s_at_100F 1.0
    lbm/s_at_300F
  • no fire suppression agent released

20
  • FOUNDATION TESTING
  • Test Results (continued) - Varying RTD/Fuel-Spray
    Fire Intensity
  • Created averaged temperature profile from data
    for each set of 3 tests
  • 8 thermocouples, sta 453, 4 (102 mm) 8 (204
    mm) above core, 2_at_0130, 0430, 0730, 1030
  • 1 thermocouple buried in tube array,
    approximately sta 510 (515), 1200
  • 1 thermocouple mounted on door exterior, sta 514,
    1130
  • 2 thermocouples, sta 518, 4 8 above core,
    1200
  • 4 thermocouples, sta 532, 4 8 above core,
    2_at_0100, 1100
  • 6 thermocouples, sta 551 upper, 4 8 above
    core, 2_at_0130, 1030, 1200
  • Calculated a relative heat production reference
    to compare combustion intensity
  • calculated areas under the averaged temperature
    traces from 30 to 80 seconds
  • summed all areas for thermocouples affected by
    fire (stas 510, 514, 518, 532, 551)
  • subtracted area for sta 453 thermocouples to
    remove heat present in air stream

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27
  • FOUNDATION TESTING
  • Test Results (continued) - Residual Fire
    Investigation/Fuel Ignition
  • Ran pool fire tests and recorded temperature
    profiles
  • Purposes
  • determine which fuels can be ignited in the
    residual fire scenario
  • use data to refine MPSE revision 3
  • Fixture geometry
  • master fuel pan in the simulator filled to make a
    water bath
  • smaller stainless steel fuel pan located in the
    water bath
  • Test conditions
  • fuels JP-8, oil (Mobil Jet Oil II), hydraulic
    fluid (Skydrol LD-4)
  • fuel quantity 0.47 gallon (1 deep puddle) in
    10.5 x 10.3 x 1.5 deep pan
  • fuel temperature prior to test 150F (by
    thermocouple submerged in fuel)
  • ignition exposure 10 - 30 seconds
    intermittently for 3 minutes
  • ventilation conditions 2.2 lbm/s_at_100F 1.0
    lbm/s_at_300F
  • no fire suppression agent released

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30
  • FOUNDATION TESTING
  • Test Results - Conclusions
  • Fire intensity
  • clean simulator cross section was an insufficient
    threat
  • secondary ignition elements required to maintain
    sufficient threat
  • Varying RTD
  • no significant difference noted between releasing
    agent based on consistent preburn or tube array
    temperature
  • fuel types have varying energy signatures -
    expect impact on RTD to be noticeable
  • JP-8 worst case for 2.2 lbm/s air flow_at_100F
  • oil selected as worst case for 1.0 lbm/s air
    flow_at_300F
  • tube array has a life span of 10 fire tests
  • variation in environmental conditions observed as
    a noticeable impact
  • Residual fire scenario
  • JP8 was the only fuel ignited - oil and hydraulic
    fluid were not
  • remaining tests are incomplete

31
  • NEAR TERM PLANS
  • Complete foundation testing
  • Determine the impact/relevance of HSI on the
    residual fire scenario
  • Determine the impact of altering the fuel surface
    geometry in the residual fire scenario on
    combustion intensity
  • Ultimately, need to bench-mark Halon 1301 in
    this scenario in some manner
  • Finalize MPSE revision 3
  • Discuss/resolve issues
  • incorporate results of foundation testing
    completed to date
  • agent - storage/distribution criteria
  • final process - need to methodically evaluate
    replacement candidates without excessive test
    counts
  • Commit process to paper
  • Complete Testing for the replacement candidates
    by Jun 2003
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