Development of a Next-Generation Burner for Testing Thermal Acoustic Insulation Burnthrough Resistance

Presented to: International Aircraft Materials Fire Test Working Group – Sao Jose Dos Campos, Brazil

By: Robert Ian Ochs

Date: Tuesday, March 4, 2008

Federal AviationAdministrationDevelopment of a Next-

Generation Burner for Testing Thermal Acoustic Insulation Burnthrough Resistance

NexGen Burner Development 2Federal AviationAdministrationMarch 4, 2008

Outline

• Background• Next Generation Burner Design• Operational Parameters• Proof of Concept• Construction and Calibration of Multiple

NexGen Burners• Comparative Testing of NexGen Burners at

Various Locations


Background

• Final Rule on thermal acoustic insulation burnthrough was issued in August 2003, but the compliance date was delayed until September 2009– Airframe manufacturers had concerns with the

availability and reliability of the specified test apparatus (Park DPL 3400 oil burner)

• The Park oil burner was found to be out of production• Two different types of DPL 3400 were manufactured over

the years, producing different flames


NexGen Burner Concept• Initial Concept:

– Compressed air metered with a sonic nozzle (critical flow venturi)

– Fuel provided by a pressurized fuel tank

– Utilize the original Park draft tube components

• Stator• Igniters• Nozzle• Turbulator

– By using the same components and matching the air velocity and fuel flow rate, the overall character of the flame is unchanged


NexGen Burner Design

Cone

Turbulator

Fuel Nozzle

Igniters

StatorDraft Tube

Housing

Cradle

Muffler

Sonic Orifice

Pressure Regulator



Solenoid or manual ball valve

Pressure Regulator (in the range of 0-150 psig)

e.g., Bellofram Type 70 Pressure Regulator, 2-150 psig, max 250 psig inlet, approx $79

Fuel

Air/N2 @ ~120 psig

Solenoid or manual ball valve

Compressed gas (from bottled Nitrogen or Air, or air compressor, if it is capable

VentPressurized Air Inlet

Nozzle 5.5 GPH 80 deg-PL

Vent to lab or outdoors

Pressure Vessel (for example, McMaster-Carr p/n 1584K7, ASME-Code Vertical Pressure Tank W/O Top Plate, 15 Gallon Capacity, 12" Dia X 33" L, $278.69) or any suitable pressure vessel that can withstand pressures of around 150 psig.

Fuel Fill

Fuel Outlet This schematic is pretty basic. You can supplement this design with whatever instrumentation you would like to obtain the required data or to make for easier operation. Some examples would be a pressure transducer, remotely operated solenoid valves, fuel flow meter, etc.

Pressurized Fuel SystemSolenoid or manual ball valve

High pressure liquid level sight gauge (We use McMaster Carr p/n: 3706K23)

Needle valve to control venting

Ice Bath

H2O


Air Velocity Observations

Exit Velocity as a Function of Inlet Air Temperature

0

500

1000

1500

2000

2500

0 20 40 60 80 100 120

Inlet Pressure, psig

Exit

Velo

city

, fpm

Air Temp = 50°FAir Temp = 110°F

EXIT VELOCITY AS A FUNCTION OF TEMPERATURE, 60 PSIG

1280130013201340136013801400142014401460

0 20 40 60 80 100 120

TEMPERATURE, DEG. F

VEL

OC

ITY,

FPM


Flowrate as a Function of Temperature, Nozzle "A", 120 psig

5.76

5.65

5.58

5.55

5.6

5.65

5.7

5.75

5.8

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140

Temperature

Flo

wra

te, g

ph

Comparison of Fuel Density

775780785790795800805810815820825

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140

Temperature, °FD

ensi

ty, k

g/m

3

JP8 @ FAATCJet-A @ Boeing

Fuel Temperature Observations


Insulated Beverage Cooler 72 qt. capacity

Air Cooling

Water in/out

Fuel Cooling

Fuel in/out

Ice / Water Mixture

Ice Bath


Heat Exchange System

Fuel Tank

Water Pump

Air From Compressor

Condensate Separator

McMaster-Carr p/n 43775K55

BurnerCooler w/ice water

Blue = Water Lines

Orange = Fuel Lines

Black = Air Lines

Heat Exchanger

McMaster-Carr p/n 3865K78


Burner Operational Parameters

• Fuel– Type: JP8, Jet A or equivalent– Nozzle: Monarch 5.5 gph 80°PL– Pressure: 120 psig (±2 psig)– Temperature: 42°F (±10°F)– Flowrate: 6.0 gph (±0.3 gph)

• Air– Pressure: 60 psig (±2 psig)– Temperature: 50°F (±10°F)– Mass Flow Rate: 66 SCFM (dictated by pressure)


Flame Temperature Measurement

18001820184018601880190019201940196019802000

Thermocouple, Left to Right

Tem

pera

ture

, ºF

Measurement 1Measurement 2


Proof of Concept: RRVIII-Mat’l A

0

20

40

60

80

100

120

FAAFlanged

FAASocket

FAASocket 2

NexGen Lab C Lab I Lab J

Bur

nthr

ough

Tim

e, se

c.

Average = 95.3 sec.


Proof of Concept: RRVIII-Mat’l B

0

50

100

150

200

250

300

350

FAAFlanged

FAASocket

FAASocket 2


Bur

nthr

ough

Tim

e, se

c.

Average = 265.9 sec.


Proof of Concept: RRVIII-Mat’l C

0

50

100

150

200

250

FAAFlanged

FAASocket

FAASocket 2


Tim

e to

Exc

eed

2.0

BT

U/ft

2 *s, s

ec.

Average = 100.7 sec.


Repeatability – Relative Standard Deviation

0

5

10

15

20

FAAFlanged

FAASocket

FAASocket 2


Rel

ativ

e St

anda

rd D

evia

tion,

%


Summary of Concept Phase

• A burner can be fabricated from easily obtainable parts and materials

• By replicating the input/output parameters of the Park oil burner, the concept burner could deliver a flame similar in character to that of the Park

• The concept burner’s burnthrough performance was shown to be similar to the FAA Park oil burner, as well as several other “socket” type Park oil burners

• A better method of measuring the burner performance is desired with a higher level of accuracy


Construction and Calibration of Multiple Burners• Objective

– Construct 10 identical burners– Show reliability of performance from test to test (one burner)– Show repeatability of burner performance from burner to burner– Show reproducibility of burner performance at various locations

• Procedure– Assemble and designate a burner (i.e., NG1, NG2, etc.)– Burner components are unique to each designated burner (stator,

turbulator, cone, fuel rail, fuel nozzle, pressure regulator, muffler, sonic orifice)

– Measure burner performance at FAATC lab (fuel flow, air flow, flame temperature, burnthrough times)

– Package burner, ship to participating laboratory– Lab will perform same tests and compare results– If results are similar to those obtained at the FAATC, then burner is

performing properly


NexGen Burner Distribution

• Currently, NexGen burners are located at:– NG1: CEAT, Toulouse, France– NG2: FAATC– NG3: FAATC– NG4: Mexmil, Santa Ana, CA, USA– NG5: AIRBUS, Bremen, Germany– NG6: BOEING, Seattle, WA, USA– NG7: FAATC– NG8: JEHIER, Chemile, France– NG9: FAATC– NG10: FAATC

• Parts for more burners will be ordered soon!


New Blanket Holder

• Lightweight PAN (TexTech) materials have been found to have a high level of consistency with characteristic burnthrough times related to the material density (8579 or 8611)

• These materials were also found to be greatly affected by the original blanket holder, the test rig that simulates the structure of an aircraft fuselage

• A new sample holder was designed to increase the consistency of the burnthrough times in order to isolate the performance of the NexGen burners from all other effects


Picture Frame Blanket HolderINNER FRAME

OUTER FRAME

SUPPORTS


Picture Frame Blanket Holder


Frame Alignment

Centerline of picture frame (9.125”) is aligned with centerline of cone

CL

CL

4” from cone face to blanket surface


Material will typically shrink within 20 sec. from the top and the sides. The center portion, where the burnthrough is occurring, will not be affected by this.

Testing


Picture Frame Initial Results• High level of repeatability was

observed– Identical results observed with

the FAA Park and the NexGen– Much higher level of

repeatability– Relative Standard Deviation

decreased by a factor of 10

229 229

0

50

100

150

200

250

FAA Flanged Park NexGen

Bur

nthr

ough

Tim

e, se

c.

10

12

0.7

2.6

0

2

4

6

8

10

12

14

FAA Park NexGen

Burner

RSD

%

Original Blanket HolderPicture Frame


NexGen Comparative Test Results

0

50

100

150

200

250

19394-8611R 19395-8611R 19391-8579R 19391A-8579R 19392A-8579R

MATERIAL

AV

ER

AG

E B

T TI

ME

, SE

C

FAA PARK

FAA NG1

FAA NG4

FAA NG5

FAA NG7

FAA NG8

Boeing NG6

CEAT NG1

Mexmil NG4


NexGen Repeatability

0.00

1.00

2.00

3.00

4.00

5.00

6.00

19394-8611R 19395-8611R 19391-8579R 19391A-8579R 19392A-8579R

MATERIAL

% S

TD D

EV

FAA PARK

FAA NG1

FAA NG4

FAA NG5

FAA NG7

FAA NG8

Boeing NG6

CEAT NG1

Mexmil NG4


Material Averages216.4 224.2

180.7 182.5172.7

0.0

50.0

100.0

150.0

200.0

250.0

19394-8611R 19395-8611R 19391-8579R 19391A-8579R 19392A-8579R

MATERIAL

AV

ER

AG

E B

T TI

ME

, SE

C


Material Repeatability

4.4

3.7

4.8

3.6

4.7

0.0

1.0

2.0

3.0

4.0

5.0

6.0

19394-8611R 19395-8611R 19391-8579R 19391A-8579R 19392A-8579R

MATERIAL

% S

TD D

EV


Overall Averages220.01

180.96

0.00

50.00

100.00

150.00

200.00

250.00

8611 8579

MATERIAL

AV

ER

AG

E B

T TI

ME

, SE

C


Overall Reproducibility

4.41 4.41

0.0

1.0

2.0

3.0

4.0

5.0

6.0

8611 8579

MATERIAL

% S

TD D

EV


Summary of Results

• Overall, the picture frame test method was useful in determining if burners are performing properly at different locations

• The test method was found to be more repeatable and reproducible than when testing the same materials on the original blanket holder

• Although this test method provides highly accurate results, it is in no means intended to replace the original test method

• This testing method will not be required for calibrating NexGen burners; rather it can be used to ensure that a burner is not deviating from it’s original performance


Near-Future Work

• Set up and administer a picture frame round robin test with all NexGen burner labs– Tight control

• Burner input settings• Samples sent from FAA Tech Center• Conditioning of samples prior to testing• Lab test forms and data collection

– Analyze data


Muffled Muffler• During seat burner trial and error

testing, some reticulated foam was jammed into the muffler to see if it had an effect on creating a more uniform air stream

• To our amazement it muted the sound of the sonic choke to almost as quiet as a Park burner

• We then re-measured the burner exit velocity in the same manner as before with the Omega HH30 vane anemometer

• The exit velocity was unchanged

• Comparative picture frame testing is planned in order to verify the equivalence

0

500

1000

1500

2000

0 20 40 60 80 100

Inlet Pressure, psig

Exi

t Vel

ocity

, FP

M

NO FOAMFOAM


Muffled Muffler


Thermal Acoustic Insulation Blanket Comparative Testing• Boeing created 3 types of thermal acoustic

insulation specimen samples: Material A, B, and C

• Three tests worth of each material were created for each burner; therefore, each burner would run 9 tests total

• Tests were run initially at Boeing then at the tech center on the FAA Park and FAA NG4 with Boeing personnel witnessing testing


Burner Input Parameters and Backside Heat Flux - Material A - FAA Park

0

20

40

60

80

100

120

140

0 100 200 300 400 500

Time, sec.

Tem

pera

ture

, °F

0.0

0.2

0.4

0.6

0.8

1.0

1.2

Bac

ksid

e H

eat F

lux,

B

TU/ft

2s

AirTemp

FuelTempCal1

Cal2

Test Start at 2 min.

Results – FAA Park, Material A


Results – FAA NG4, Material ABurner Input Parameters and Backside Heat Flux - Material A - FAA NG4

0

20

40

60

80

100

120

140

0 100 200 300 400 500

Time, sec

Pres

sure

, psi

g, a

nd

Tem

pera

ture

, °F.

0.0

0.2

0.4

0.6

0.8

1.0

1.2

Bac

ksid

e H

eat

Flux

,BTU

/FT2

-s

AirPres

FuelPres

AirTemp

FuelTemp

Cal1

Cal2



Results – Boeing NG6, Material ABurner Input Parameters and Backside Heat Flux - Material A - Boeing NG6

0

20

40

60

80

100

120

140

0 100 200 300 400 500

Time, sec.

Pres

sure

, psi

g an

d Te

mpe

ratu

re °F

0.0

0.2

0.4

0.6

0.8

1.0

1.2

Bac

ksid

e H

eat F

lux

BTU

/FT2

-s

AirPres

FuelPres

AirTemp

FuelTemp

Cal1

Cal2



Summary

• A next-generation burner was developed for testing the burnthrough resistance of thermal acoustic insulation– The burner was constructed from readily available parts and materials– The burner performance was proven to be similar to that of the FAA

Park– The burner was shown to perform similarly when moved from one

laboratory to another– Multiple burners were constructed, and all were found to be in good

agreement with each other and the FAA Park• A method was developed for quantifying the burnthrough

performance of the NexGen burners• When testing thermal acoustic insulation blankets, the

NexGen burners provided very similar results to that of the FAA Park



Questions, Comments, Suggestions, Input?

Development of a Next-Generation Burner for Testing Thermal Acoustic Insulation Burnthrough Resistance

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