fuel tank ignition experiments at reduced oxygen concentrations

Fuel Tank Ignition Experiments at Reduced Oxygen Concentrations

Steve SummerSystems Fire Protection Working GroupWilson, NCJuly 17 – 18, 2001

Objectives

Determine the Lower Oxygen Limit of Flammability (LOLF) at altitudes varying from 0 - 40 kft.– What is the lowest O2 concentration that results in

ignition of the ullage fuel vapors?

Determine the effect of the ullage O2

concentration on the resultant pressure rise.

Test Facility

Apparatus

TH C A nalyzer

R igh t Test Track

Left Test Track

1 0 m P ressu re Vesse l

3 Ana lyze r Byp a ss

Sa m p le Line O A nalyzer

2

H eaterH eater

Spark Source

Fan

= Therm ocouple Feed through

N L ines2

H ouse A ir L ine

Apparatus

R ig h t T /C T re eL e ft T /C T re e

L iq u id J P -8 F u e lF u e l P a n

= T h e rm o c o u p le B e a d

6.0"

6.0"

ApparatusS

T H C A n a ly z e r

P re ss u re Ve s se l

S

O x y g e n A n a ly z e r

H e a te d S a m p le L in e

U n h e a te d S a m p le L in e

SS o le n o id Va lv e

T -F itt in g3 -W a y Va lv e

F lo w m e te r

P re ss u re R e g u la to r

D ia p h ra g m P u m p

B u lk h ea d F ittin g

K EY

C a l. G a s In le t

B y p a ss

T H C In ta k e

O x y g e n In ta k e

O x y g e n R e tu rn

S a m p leO v e r f lo wL o c a tio n s

Ic e -Te m p e ra tu re B a th

Test Program

Methane Validation Tests– Determine LFL of Methane at Sea Level and

compare to numbers cited in literature.– Tests performed at CH4-air concentrations ranging

from 4.35 - 5.5% CH4.

Results: Methane Validation Tests

Test Program

JP-8 LOLF Tests– Determine ullage oxygen concentration needed to

inert the fuel tank at altitudes of 0 - 40 kft.– Determine the effect of the ullage O2 concentration

on the resultant pressure rise.

Results: JP-8 LOLF Tests

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

0 10 20 30 40

Altitude (kft)

Oxy

ge

n C

on

cen

tra

tio

n b

y V

olu

me

Ignition

Non-Ignition

Minimum Oxygen Concentrations for Ignition

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

0 10 20 30 40

Altitude (kft)

Oxy

ge

n C

on

cen

tra

tio

n b

y V

olu

me

Non-Ignition

Ignition

Results: JP-8 LOLF Tests

Future Plans

Pressure measurements– Piezoresistive sensors mounted behind porous

metal discs.– Similar configuration to Joe Shepherd’s work.– Approximately 2 months before testing can begin.