05-ATA28&47-Fuel&Inerting_2012

8/12/2019 05-ATA28&47-Fuel&Inerting_2012

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Aviation Systems Design

Frederic ABADIE

[email protected]
mailto:[email protected]:[email protected]


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Frederic ABADIE

[email protected]


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Principle & Architecture

Engine fuel feed System

Refuel / Defuel System

Jettison System

Components : Fuel pumps & sensors

Cockpit Display

2012-2013 3Aviation Systems Design


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Jettison System


Cockpit Display



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Fuel Systemensures :

Fuel feed toengines and APU among all flight phases

Fuel tanks filling and emptying

Computation of fuel quantity(volume & weight) in each tank

Coolingof Aircraft elements : Hydraulic circuits, Engine Electrical

Generators...

Monitoringof the system and reporting to the pilot

Participation to Aircraft weight balancing (A/C equipped with trim tanks)

Fuel quantity is given in kilogramsor pounds(1 lb = 0.453 kg)

Fuel density ~0.785 kg/l

Jet A/A1 is the most common fuel used in aviation industry



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Example of architecture 3 tanks


Fuel feedgallery


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Jettison System


Cockpit Display



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Engine fuel feed



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Refuel / Defuel system controls : Automatic or Manual refuel

Manual defuel

Manual ground transfer between the tanks


An external Fuel Control Panel allows tolaunch manualand auto refuel / defueland ground transfer

Fuel Control Computer manages the refuel /defuel / ground transfer and monitors

fuel quantity andquality


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Aircraft Refuelling


Refuel couplingsare connected tothe refuel gallery

through anisolation valve

Defuel / Jettison valves are usedfor pressure defuel or ground transferby connecting Engine feed gallery to Refuel gallery

Refuel gallery isconnected to each tank

through inlet valves


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12/322012-2013 12Aviation Systems Design


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Jettison System


Cockpit Display



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Fuel Pumps

At least 2 fuel pumps are installed in each tank (for redundancy). They areconstantly fed with fuel to avoid air ingestion.

Fuel pumps are the only equipment within the tanksrequiring high electrical power.To prevent ignition :

Pumps are installed in self-contained explosive canisters

All electrical harnesses are EXTERNAL to fuel tanks

Override pumps are usually installed in centre tankto forcecentre tank to be emptied first for flight

performanceand ETOPS / LROPS(*)considerations

Engines can be fed by gravity fuel feed from outer tanks when pumps fail

Fuel pumps allow to re-circulate fuel to avoid freezing and to reachhomogeneous fuel quality in all tanks


(*)Extended range Twin-engine Operation Performance StandardLong Range Operational Performance Standard


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Fuel sensors

Fuel sensors are powered at low voltage (< 5V) and installed as far aspossible from elements connected to electrical ground

Capacitive fuel gauges

Used for fuel level indication

Up to 150 gauges per Aircraft

Densitometers

Allow to calculate the weightcorresponding to the measuredvolume

Vibrating device : resonance frequency varies with fuel density

Temperature sensors

Standard thermal resistance

Temperature = f (resistance)


R R: Radius of gauge cylinders

r: permittivity of Air

0 : permittivity of Fuel


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Jettison System


Cockpit Display



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Example of ECAM Fuel page


1 Trim Tank

4 Wing Tanks

1 Centre Tank

Valve normallyopen

Valve normallyclosed

Pump normally inStand by

Pump normallyrunning


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Frederic ABADIE

[email protected]


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Why inerting ?

Regulation

System Architecture

Components :

Air Separation Module

Ozone converter Inerting Control Computer



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Why inerting ?

Regulation

System Architecture

Components :





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Fuel tank explosion is possible when 3 elements get together :

Fuel vapour

Oxygen

Ignition source

Historical approach (starting 60s):

To reduce fuel flammability, Airworthiness Authorities used to request toprevent thepresence of possible ignition sources in fuel tanks

But accidents have shown that empty centre tanks are exposed to explosion risk


Fuel

Fire O2

Jet A flammability


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5 accidents caused by fuel vapour explosion


2 Lightning strikes :

B707 1963

B747 1976

2 on ground :

B737-400 2001B737-300 1990

B747-100 19961 in flight
http://c/Users/to13443/My%20Documents/Dropbox/Lectures/Videos/TWA_Flug_800.avi


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Why inerting ?

Regulation

System Architecture

Components :





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SFAR(*)88 finalised Dec. 2002, requires to :

Conduct a revalidation of the fuel tank system designs on the existingfleet of transport category airplanes carrying 30 or more passengers or apayload of 7,500 lbs. or more

Develop all design changes required to demonstrate they meet the new

ignition prevention requirements

2012-2013 24Aviation Systems Design(*) Special Federal Aviation Regulation

Fuel

Fire O2

Heat sources

Ullage = air / fuel vapour

Fuel

O2 concentration :

< 12% on ground

(< 15,5% at 40 000 ft)

New requirement : Fuel tank


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Why inerting ?

Regulation

System Architecture

Components :


Ozone converter

Inerting Control Computer



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OZONE converter to

protects ASMs

12

3

4

5

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FTIS : Fuel Tank Inerting

System IGGS : Inert Gas Generation

SystemOBIGGS : On Board IGGS


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Why inerting ?

Regulation

System Architecture

Components :


Ozone converter




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Air Separation Module is the main element with Inerting System

ASMs separate air into Nitrogen Enriched Stream(NEA) & Oxygen Enriched Stream (OEA)

NEAis directed to fuel tanks via 1 or

several injection points

OEAis directed overboard via

dedicated port

Incoming air shall be temperature controlled :

- To optimize ASM performance (60C +/- 10%)

- To ensure ASM cartridges life saving (< 90C)



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Ozone converter Protects ASMs from OZONE which

degrades ASM life

Ozone converter core incorporates precious

metal (manganese oxide) allowing

catalyst reduction of O3 into O2

Effectiveness of catalyst metal degradesover time, due to bleed air contaminants

Typical efficiency :

96% @200C (new)

85% after 600 Flight Hours


Ozone converters are also used

to reduce O3 level in Cabin Air

Ozone concentration above 5 ppm

presents risks for human health

Density of ozone : 2.14 kg/m3Density of air : 1.29 kg/m3Ozone half-life :

3 months @ -50C3 days @+20C


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Commands inerting function depending on flight phase


Source :Flight-testing of the FAAOnboard Inert Gas GenerationSystem on an AIRBUS A320

(June 2004)
http://www.fire.tc.faa.gov/2004Conference/files/fuel/B.Cavage_Flight_testing_inert_gas_generation_system.pdfhttp://www.fire.tc.faa.gov/2004Conference/files/fuel/B.Cavage_Flight_testing_inert_gas_generation_system.pdfhttp://www.fire.tc.faa.gov/2004Conference/files/fuel/B.Cavage_Flight_testing_inert_gas_generation_system.pdfhttp://www.fire.tc.faa.gov/2004Conference/files/fuel/B.Cavage_Flight_testing_inert_gas_generation_system.pdfhttp://www.fire.tc.faa.gov/2004Conference/files/fuel/B.Cavage_Flight_testing_inert_gas_generation_system.pdfhttp://www.fire.tc.faa.gov/2004Conference/files/fuel/B.Cavage_Flight_testing_inert_gas_generation_system.pdfhttp://www.fire.tc.faa.gov/2004Conference/files/fuel/B.Cavage_Flight_testing_inert_gas_generation_system.pdfhttp://www.fire.tc.faa.gov/2004Conference/files/fuel/B.Cavage_Flight_testing_inert_gas_generation_system.pdf


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Drives Inerting systems valves to regulate :

Incoming air flow temperature (~ 60C) through heat exchanger

Incoming air flow pressure and flow through Bleed inlet valve

Switches between Low / Mid / High flow of NEA towards fuel tanks bydriving Dual Flow Shut Off Valve

Allows to isolate the IGGS from the fuel tank

Provides Systemmonitoring information to the crew

Report System status through BITE function



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Questions ?

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