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Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International Fire and Cabin Safety Research Conference Atlantic City, NJ Richard E. Lyon and David Blake FAA William J. Hughes Technical Center November 1, 2007

Federal Aviation Administration Heat Release Rate in Cargo ... · Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International

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Page 1: Federal Aviation Administration Heat Release Rate in Cargo ... · Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International

Federal AviationAdministration

Heat Release Rate in Cargo Fires

Presented to: The Fifth Triennial International Fire and Cabin Safety Research Conference

Atlantic City, NJ

Richard E. Lyon and David Blake

FAA William J. Hughes Technical Center

November 1, 2007

Page 2: Federal Aviation Administration Heat Release Rate in Cargo ... · Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International

Federal AviationAdministration 2Heat Release Rate: Cargo Fires

November 1, 2007

OBJECTIVEOBJECTIVE

Measure release rate of combustion products from object(s) burning in a ventilated cargo compartment.

Use data as source term in CFD modeling of smoke movement in cargo compartment.

Page 3: Federal Aviation Administration Heat Release Rate in Cargo ... · Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International

Federal AviationAdministration 3Heat Release Rate: Cargo Fires

November 1, 2007

MIXED PLASTIC SMOKE GENERATION SOURCEMIXED PLASTIC SMOKE GENERATION SOURCE

100 mm

Flaming ModeIn Cargo

CompartmentSimulates Burning Luggage

Page 4: Federal Aviation Administration Heat Release Rate in Cargo ... · Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International

Federal AviationAdministration 4Heat Release Rate: Cargo Fires

November 1, 2007

APPROACHAPPROACH

Use perfect mixing model to relate exhaust gas concentration to

combustion product release rate in (cargo) compartments.

Page 5: Federal Aviation Administration Heat Release Rate in Cargo ... · Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International

Federal AviationAdministration 5Heat Release Rate: Cargo Fires

November 1, 2007

EXPERIMENTALEXPERIMENTALGenerate known combustion product histories with a premixed propane-air burner.

Apply a perfect mixing model to exhaust gases drawn from cargo compartment.

Compare mixing model to:- oxygen consumption (heat release rate)

history.- temperature history.

Page 6: Federal Aviation Administration Heat Release Rate in Cargo ... · Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International

Federal AviationAdministration 6Heat Release Rate: Cargo Fires

November 1, 2007

PROCEDUREPROCEDURE

• Position premixed propane-air burner at center of B707cargo compartment.

• Attach thermocouple to ceiling directly above burner.

• Measure exhaust gas flow rate (F) and [O2].

• Calculate HRR from F, Δ[O2] using spread-sheet mixingmodel.

• Test effects of forced circulation on results.

Page 7: Federal Aviation Administration Heat Release Rate in Cargo ... · Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International

Federal AviationAdministration 7Heat Release Rate: Cargo Fires

November 1, 2007

TEST CONFIGURATIONTEST CONFIGURATION

Page 8: Federal Aviation Administration Heat Release Rate in Cargo ... · Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International

Federal AviationAdministration 8Heat Release Rate: Cargo Fires

November 1, 2007

B707 CARGOB707 CARGOCOMPARTMENTCOMPARTMENT

ExhaustExhaustDuctDuct

PropaneBurner

Location

ThermocoupleThermocouple

Page 9: Federal Aviation Administration Heat Release Rate in Cargo ... · Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International

Federal AviationAdministration 9Heat Release Rate: Cargo Fires

November 1, 2007

Fin Fout

[O2]in [O2]out

ρFin = ρFout = ρF

[O2]in - [O2]out = Δ[O2] = θ

Propane Burner

CargoCompartment

PERFECT MIXING MODELPERFECT MIXING MODEL

MASS BALANCE:

SPECIESBALANCE:

Page 10: Federal Aviation Administration Heat Release Rate in Cargo ... · Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International

Federal AviationAdministration 10Heat Release Rate: Cargo Fires

November 1, 2007

HRR(t) = ρFE

τ =Compartment Volume (m3)

Flow Rate (m3/s)

MIXING MODEL SOLUTION FOR HRRMIXING MODEL SOLUTION FOR HRR

θ + τ d θd t

Page 11: Federal Aviation Administration Heat Release Rate in Cargo ... · Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International

Federal AviationAdministration 11Heat Release Rate: Cargo Fires

November 1, 2007

TEST PARAMETERSTEST PARAMETERSCargo compartment volume = 26 m3

Exhaust flow rate, F = 0.018 m3/s

Heat of combustion of oxygen, E = 12.78 MJ/kg-O2 (propane)

Ambient temperature, T = 27 °C (81 °F)

Air Density (27 °C), ρ = 1.2 kg/m3

Page 12: Federal Aviation Administration Heat Release Rate in Cargo ... · Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International

Federal AviationAdministration 12Heat Release Rate: Cargo Fires

November 1, 2007

FORCED CIRCULATION

-2

0

2

4

6

8

0 5 10 15 20

Hea

t Rel

ease

Rat

e (k

W)

HRRHRR(propane(propaneburner)burner)

Time (minutes)

Fan

No Fan

• Small improvement in fidelity

• But could spread flames

Page 13: Federal Aviation Administration Heat Release Rate in Cargo ... · Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International

Federal AviationAdministration 13Heat Release Rate: Cargo Fires

November 1, 2007

HRR STEP CHANGEHRR STEP CHANGE

30

40

50

60

70

80

90

0 10 20 30 40 50 60 70 80

.003

.004

.005Propane Flow Rate

Oxy

gen

Con

cent

ratio

n(v

/v)

Ceiling Temperature

[O2] (v/v)

.185

.190

.195

.200

.205

.210

Time (minutes)

Temperature (°C

)m

3 /min

Page 14: Federal Aviation Administration Heat Release Rate in Cargo ... · Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International

Federal AviationAdministration 14Heat Release Rate: Cargo Fires

November 1, 2007

HRR MODEL CALIBRATIONHRR MODEL CALIBRATION

0.185

0.190

0.195

0.200

0.205

0.210

0.215

0 10 20 30 40 50 60 70 80

Experimental Data

Best Fit of Model

Time (minutes)

Oxy

gen

Con

cent

ratio

n (v

/v)

Δ[O2] for Step Change HRR

Page 15: Federal Aviation Administration Heat Release Rate in Cargo ... · Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International

Federal AviationAdministration 15Heat Release Rate: Cargo Fires

November 1, 2007

CALIBRATION RESULTSCALIBRATION RESULTS(Propane Burner Step Change HRR)(Propane Burner Step Change HRR)

Parameter

ρFE (kW)

τ (min)

Measured(Best Fit)Calculated

276 270 ± 10

24 28

Page 16: Federal Aviation Administration Heat Release Rate in Cargo ... · Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International

Federal AviationAdministration 16Heat Release Rate: Cargo Fires

November 1, 2007

0

2

4

6

8

10

0 10 20 30 40 50 60 70 80

Hea

t Rel

ease

Rat

e, k

W

Time (minutes)

Model HRR (τ = 0)

Model HRR (τ = 28 min)HRR (Propane burner)

HRR STEP CHANGE HRR STEP CHANGE

Page 17: Federal Aviation Administration Heat Release Rate in Cargo ... · Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International

Federal AviationAdministration 17Heat Release Rate: Cargo Fires

November 1, 2007

HRR SQUARE WAVEHRR SQUARE WAVE

-1

0

1

2

3

4

5

6

7

0 5 10 15 20

Hea

t Rel

ease

Rat

e, k

W

Time (minutes)

Model HRR(τ = 0)

Model HRR(τ = 28 min)

HRR (Propane burner)

Page 18: Federal Aviation Administration Heat Release Rate in Cargo ... · Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International

Federal AviationAdministration 18Heat Release Rate: Cargo Fires

November 1, 2007

6 kW

4 kW

3 kW

2 kW

Propane Burner Flame Heights

MULTIMULTI--STEP HRR STEP HRR HISTORIESHISTORIES

Page 19: Federal Aviation Administration Heat Release Rate in Cargo ... · Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International

Federal AviationAdministration 19Heat Release Rate: Cargo Fires

November 1, 2007

-1

0

1

2

3

4

5

6

7

20

30

40

50

60

70

80

0 5 10 15 20 25 30 35 40

hrrun8

Time (minutes)

HR

R (k

W)

Temperature (°C

)HRR

(propaneburner)

Temperature

HRR(model)

MULTIMULTI--STEP HRR 1STEP HRR 1

Page 20: Federal Aviation Administration Heat Release Rate in Cargo ... · Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International

Federal AviationAdministration 20Heat Release Rate: Cargo Fires

November 1, 2007

MULTIMULTI--STEP HRR 2STEP HRR 2

-1

0

1

2

3

4

5

6

7

20

30

40

50

60

70

80

0 5 10 15 20 25 30 35 40

hrrun3H

RR

(kW

)

Time (minutes)

Temperature (°C

)

HRR (PropaneBurner)

Temperature

HRR (model)

Page 21: Federal Aviation Administration Heat Release Rate in Cargo ... · Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International

Federal AviationAdministration 21Heat Release Rate: Cargo Fires

November 1, 2007

Temperature versus HRR for MultiTemperature versus HRR for Multi--Step Step HistoriesHistoriesTe

mpe

ratu

re (°

C)

Heat Release Rate (kW)

20

30

40

50

60

70

80

-1 0 1 2 3 4 5 6 7

HRR IncreasingHRR Decreasing

Page 22: Federal Aviation Administration Heat Release Rate in Cargo ... · Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International

Federal AviationAdministration 22Heat Release Rate: Cargo Fires

November 1, 2007

DISCUSSIONDISCUSSIONMixing Model and Temperature Provide Comparable (R = 0.8) Resolution of Combustion Histories for Objects Burning in Compartments.

Advantage of Combustion Model is:• Measures Heat Release Rate• Easily Calibrated• Independent of Size and Position of

Burning Object(s) with good mixing.

Page 23: Federal Aviation Administration Heat Release Rate in Cargo ... · Federal Aviation Administration Heat Release Rate in Cargo Fires Presented to: The Fifth Triennial International

Federal AviationAdministration 23Heat Release Rate: Cargo Fires

November 1, 2007

CONCLUSIONSCONCLUSIONS

Mixing Model Provides Reasonable Combustion Product Release Rates and Histories for Objects in Compartments When-

Burning Time ≤ τ ≈Compartment Volume

Exhaust Flow Rate