radiation in case of fire in tank farms

DIPTEMDIPTEMUniversitUniversitàà di Genovadi Genova

Giornata UIT antincendio, Modena, 26 giugno 2007

Pag. 1 / 40

Radiation evaluation for safety system design in case of fire in tank farms

The solid flame model and some considerations on CFD results

UniversitUniversitàà degli studi di Genovadegli studi di Genova

DIPTEM, Dipartimento di Ingegneria della DIPTEM, Dipartimento di Ingegneria della produzione, produzione, TermoenergeticaTermoenergetica e Modelli e Modelli MatematiciMatematici

M.FossaM.Fossa Giornata UIT dellGiornata UIT dell’’ingegneria antincendioingegneria antincendioModena 26 giugno 2007Modena 26 giugno 2007



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PRESENTATION CONTENTS PRESENTATION CONTENTS

1.1. TheThe Department of Production, Thermal Energy and Department of Production, Thermal Energy and Mathematical Models, Mathematical Models, DiptemDiptem

2.2. Fire in tank farms: hazards, risk control, safety Fire in tank farms: hazards, risk control, safety apparatuses for tank cooling,apparatuses for tank cooling, existing existing standardsstandards

3.3. The evaluation of the thermal radiation from a pool The evaluation of the thermal radiation from a pool fire: the solid flame modelfire: the solid flame model

4.4. The solid flame model: predictions and validation The solid flame model: predictions and validation against experimental resultsagainst experimental results

5.5. Some results from CFD analysis, the FDS code by NISTSome results from CFD analysis, the FDS code by NIST



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11

FactFact and and figuresfigures on the University of on the University of Genova and Genova and DiptemDiptem DepartmentDepartment



Pag. 4 / 40

DiptemDiptem, , Department ofDepartment of Production,Production,

ThermThermal al EngineeringEngineering andand Mathematical ModelsMathematical ModelsDIPTEM arises from the fusion of DIP, DITEC and DIMET departments. As a consequence, the teaching staff is devoted and operates in various fields of research from industrial systems to energyand from environmental control to mathematical modeling. Moreover, these matters are the bases on which many disciplines like mechanical technology and economy, heat transfer and air conditioning, energetics and material technology, production management and applied thermodynamics are founded. These disciplines interact with the area of mathematical models which, therefore, turns out to be both an indispensable cultural element and the sign of the real interdisciplinary character of the department.

The department is articulated in three divisions

ProductionEngineering

Mathematical Methods and Models

Thermoenergetics andEnvironmental Engineering, Tec



Pag. 5 / 40

DiptemDiptem, , Thermoenergetics Thermoenergetics DivisionDivision, TEC, TEC

Energetics and applied thermodynamics:Efficient use of energy in civil and industrial field. Renewableenergy sources, energy conversion processes and refrigeration.Single and multiphase thermofluid-dynamics :Energy and mass transfer phenomena with applications to cryogenics, nanotechnology, space-systems and electronic equipment, optical techniques in heat transfer.Environmental comfort and applied acoustics:Environmental comfort design: air quality, acoustic and visual comfort, optimal thermo hygrometric conditions.Design of air conditionings systems:Thermal behavior of buildings, air conditioning systems management, building-system interaction.Thermophysical properties of materials:Thermophysical properties analysis with references to thermal insulation of materials. Radiant properties of surfaces.www.ditec.unige.it

Research Topics



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Marco Fossa, PhD, A/Professor•Areas of interest: exp. heat transfer, two-phase flow, renewable energies

FireFire modellingmodelling researchresearch groupgroupFrancesco Devia, PhD, Research Professor

•Areas of interest: CFD, modelling, fire dynamics

Giovanni Tanda, PhD, Full Professor•Areas of interest: optical techniques in heattransfer, natural convection and radiationmeasurements

The research is supported by the NationalCompany for Hydrocarbons, ENI Refining and Marketing Division



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22

Fire in tank farms: hazards, risk Fire in tank farms: hazards, risk control, safety apparatuses for tank control, safety apparatuses for tank

cooling,cooling, existing normsexisting norms



Pag. 8 / 40

Hazards and risk controlHazards and risk control (I) (I)

Pool Pool firesfires from storage tanks of hydrocarbons from storage tanks of hydrocarbons represent probably the most dangerous situation represent probably the most dangerous situation for surrounding structures and personsfor surrounding structures and personsRadiationRadiation is usually the dominant mode of heat is usually the dominant mode of heat transfer to the surroundingstransfer to the surroundings

In such a situation, the In such a situation, the priority is priority is to preserve the to preserve the facing tanks from ignitionfacing tanks from ignitionby means of water cooling by means of water cooling of irradiated surfacesof irradiated surfaces



Pag. 9 / 40

Hazards and risk controlHazards and risk control (II) (II)

In order to evaluate the In order to evaluate the hazards hazards associated to a pool fire scenarioassociated to a pool fire scenario a a reliable estimation of the reliable estimation of the heat heat radiatedradiated by the flame is mandatory. by the flame is mandatory.

The knowledge of the The knowledge of the power irradiated to the power irradiated to the surroundings is the base surroundings is the base for the design offor the design of fixed fixed safety equipment for safety equipment for tank cooling tank cooling operating in operating in automatic modeautomatic mode

water

ring

watersupply pipe



Pag. 10 / 40

Hazards and risk controlHazards and risk control (III) (III)

••StandarsStandars do not provide congruent valuesdo not provide congruent values••They do not consider the fuel type or tank They do not consider the fuel type or tank interdistanceinterdistance••They only prescribe minimum water flow rates per sq. meter of They only prescribe minimum water flow rates per sq. meter of tank surface (2tank surface (2~8 liters/(min m~8 liters/(min m22) )) )••They allow the They allow the water flow rates to be inferred from energy water flow rates to be inferred from energy balancesbalances based on irradiance knowledgebased on irradiance knowledge

International and Italian International and Italian standards on fire protection standards on fire protection regarding water cooling rates:regarding water cooling rates:

NFPANFPA 15, 15, APIAPI 2510A, 2510A, SHELLSHELL depdep 80.47.10.3080.47.10.30--gen, gen, AGIPAGIP 2024420244

NationalNational lawslaws: DPR 29 luglio 1982 n. 577, : DPR 29 luglio 1982 n. 577, D.D. LgsLgs. 17 agosto 1999 n. 334, D.M. . 17 agosto 1999 n. 334, D.M. 9/5/2001, D.M. 9 Maggio 20079/5/2001, D.M. 9 Maggio 2007



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33

The evaluation of the thermal radiation The evaluation of the thermal radiation from a pool fire: the solid flame from a pool fire: the solid flame

modelmodel



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ApproachesApproaches toto the pool the pool firefire radiationradiationestimationestimation

In order to evaluate the hazards associated to a pool fire scenaIn order to evaluate the hazards associated to a pool fire scenario a rio a reliable estimation of the heat radiated by the flame is mandatoreliable estimation of the heat radiated by the flame is mandatory. ry.

The usual strategy to estimate the radiation from a pool fire isThe usual strategy to estimate the radiation from a pool fire isbased on the assumptions that the flame is a stable surface whosbased on the assumptions that the flame is a stable surface whose e parameters (temperature, parameters (temperature, emissivityemissivity, area) do not vary in space and , area) do not vary in space and time. This is called thetime. This is called the Solid Flame Model,Solid Flame Model, based on a proper set based on a proper set of empirical correlationsof empirical correlations

Another approach is the Another approach is the CFD analysisCFD analysis, taking into account the , taking into account the chemical kinetics and the heat transferred by radiation in a 2 ochemical kinetics and the heat transferred by radiation in a 2 or 3 r 3 dimensional environmentdimensional environment



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The The solidsolid flameflame modelmodel

This method is based on the choice of a This method is based on the choice of a proper set of empirical formulas for flame proper set of empirical formulas for flame parameters (burning rate, emissive power, parameters (burning rate, emissive power, flame dimensions, etc). flame dimensions, etc).

The The solid solid flame(SF)flame(SF) is assumed to be a is assumed to be a tilted cylinder, tilted cylinder, due to the action of winddue to the action of wind

The geometry of the flame is defined by the The geometry of the flame is defined by the diameter of the pool D, by the cylinder diameter of the pool D, by the cylinder length L, by the tilt angle. length L, by the tilt angle.

The problem requires a suitable model for The problem requires a suitable model for radiation propagation in terms of air radiation propagation in terms of air trasmissivitytrasmissivity and of and of calculation of the view calculation of the view factorsfactors

Φ

D’

θ

H rib

D

D



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The The solidsolid flameflame model: model: flameflame parametersparameters

A set of empirical correlations are the base A set of empirical correlations are the base of the solid flame model.of the solid flame model.

They derive from measurements on fuel They derive from measurements on fuel burning rate, flame temperature and burning rate, flame temperature and emissive power and on photographic emissive power and on photographic evidences regarding overall flame length, evidences regarding overall flame length, clear flame length, flame tilt in case of windclear flame length, flame tilt in case of wind

The The burning rateburning rate is the most important is the most important parameter, and it depends on fuel type and parameter, and it depends on fuel type and pool dimension. Other flame parameters pool dimension. Other flame parameters (e.g. the flame length) depends on BR(e.g. the flame length) depends on BR

Most of experimental data refer to LNG and Most of experimental data refer to LNG and LPG. Most of data refer to pool diameter LPG. Most of data refer to pool diameter less than 10mless than 10m

D’

θ

H rib

D

D



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LiteratureLiterature experimentalexperimental datadata

0.00

0.04

0.08

0.12

0.16

0.20

0 30 60 90 120 150Entalpy ratio ∆Hc/∆Hv*

max

imum

bur

ning

rat

e [k

g/sm

2 ]benzenebutaneDiesel

EthaneEthanolGasoline/PetrolHeptaneHexane

LNG/CH4LPG/Prop.MethanolNaphtha/PentaneOctaneToluene

XyleneJP4

-30%

+30%

0

10

20

30

40

50

60

70

0-2 2-5 5-10 10-20 20-30 30-40 40-50 50-60

Pool diameter [m]

N. o

f exp

erim

ents

m” = m"max (1 – e-kβ D)

Foglio di lavoro di Microsoft Excel



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RadiationRadiation propagationpropagation toto the the surroundingssurroundings

••NumericalNumerical methodsmethods::NumericalNumerical solutionsolution of the of the elementaryelementaryviewview factorfactor problemproblem, , byby integrationintegrationon on flameflame and target and target surfacesurface

⎥⎦

⎤⎢⎣

⎡⎟⎠⎞

⎜⎝⎛+⎟⎟

⎠

⎞⎜⎜⎝

⎛ −+

⎟⎠⎞

⎜⎝⎛

⎥⎦

⎤⎢⎣

⎡ ⋅+−+++−=

−−

−−

CsinFtan

FCsinFabtan

Ccos

BADtan

AB)sina1(b2)1b(aEDtanEF

12

1

122

1v

θθθ

θπ

•• AnalyticalAnalytical methodsmethods::FormulasFormulas forfor air air transmissivitytransmissivity((WayneWayne, , HottelHottel, , BagsterBagster, , RajRaj))FormulasFormulas forfor viewview factorsfactors of of tiltedtiltedcylinderscylinders FFdA2dA2--A1A1 ((HamiltonHamilton, , MorganMorganReinRein, , SparrowSparrow,, MudanMudan))

2221

21coscos dAS

dF dd πθθ

=−



Pag. 17 / 40

RadiationRadiation propagationpropagation: : analyticalanalytical methodsmethods

The The viewview factorfactor solutionssolutions are are availableavailable forfortargetstargets at at flameflame base base ((HamiltonHamilton, , MorganMorganReinRein, , SparrowSparrow,, MudanMudan))

At

Af

Af0 Lo

Lf

At

Ft-f = (Ft-(f+f0) - Ft-f0)

Target Target lowerlower thanthanflameflame basebase

Af

Af0 Lo

Lf At At Af*

Ft-f = Ft-f* + Ft-f0

Target Target higherhigherthanthan flameflame basebase

ViewView factorfactor algebra can algebra can bebeemployedemployed toto solve solve otherother simplesimpleviewview factorfactor problemsproblems



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RadiationRadiation : : DiptemDiptem numericalnumerical methodmethodThe The viewview factorfactor problemproblem isis solvedsolved by by meansmeans of a direct of a direct algorithmalgorithm (a (a proprietaryproprietary code code namednamed Fast Fast ViewView FactorFactor Solver). The code Solver). The code subsequentlysubsequently solvessolves the the problemproblem of the of the viewview factorfactor fromfrom differentialdifferentialelementselements of of bothboth flameflame and target and target surfacesurface and and itit performsperforms ananoptimisedoptimised 3D 3D integrationintegration. . BothBoth flameflame and target tank are and target tank are subdividedsubdividedintointo 101033 elementselements (Devia & Fossa, FSJ 2007)(Devia & Fossa, FSJ 2007)

∑ββ

π=−

2N

1i22

i

i2i121d A

rcoscos1F

( ) ( ) ( ) ( ) 1R

tgzzyyR

tgzzxx2

y

00

2

x

00 =⎟⎟⎠

⎞⎜⎜⎝

⎛ θ−−−+⎟⎟

⎠

⎞⎜⎜⎝

⎛ θ−−−

0.001

0.01

0.1

11 10 100

L=2

L=6

Rein et al. (1970)L=l/r X=x/r



Pag. 19 / 40

ExistingExisting solidsolid flameflame modelsmodels (I)(I)((UniformUniform emissionemission flameflame ))

••TNO, TNO, The The NetherlandsNetherlands OrganisationOrganisation of of AppliedAppliedScientificScientific ResearchResearch (Yellow Book, 1992) (Yellow Book, 1992)

••SFPE, SFPE, Soc. Soc. FireFire ProtProt. . EngineersEngineers, (, (MudanMudan, 1995), 1995)

••NRC, NRC, U.S. U.S. NuclearNuclear RegulatoryRegulatory CommissionCommission, , ((ShokriShokri & & BeylerBeyler, 1989), 1989)

••((TwoTwo layerlayer flameflame))

••HSE, HSE, U.K.U.K. HealthHealth and and SafetySafety ExecutiveExecutive ((RewRew & & HulbertHulbert, 1996), 1996)

••((ContinuosContinuos flameflame))

••FayFay, , DeptDept. . MechMech. . EngEng. MIT, 2006 (LNG . MIT, 2006 (LNG onlyonly))



Pag. 20 / 40

ExistingExisting solidsolid flameflame modelsmodels (II)(II)

Air transmissivityis notconsidered. Fuel type effecton SEP is notconsidered

NRC spreadsheet, FDT 1805

NRC Report n. 1805, 2005

Formulas forhorizontal and vertical targets, downwind, at flame base elevation

NO(SEP includestransm.)

Babrauskaskerosene, fueloil, gasoline, JP-4, JP-5, LNG

Tilted cylinderwith uniformemission

Largevalidation withexp. results

PoolFire 6HSE report96/1996

Numericalsolution (contourintegrals)

WayneRew & Hulbert

Large fueldatabase

Tilted cylinderwith non uniformemission

The effect of wind is toreduce flamelength

NOSFPE handbook

Formulas forhorizontal and vertical targets, downwind, at flame base elevation

Hottel & Sarofin

BabrauskasLNG e LPGkerosene, gasoline, JP-4 and other sootyfuels


Sep formulasrefer to smalldiameters (3m typically)

EffectsTNO Yellow Book

Formulas forhorizontal, verticaland crosswindtargets,, at flamebase elevation

BagsterBabrauskasLNG, LPG, benzene, methanol


NotesSoftwareReference

View factos and target location

Air transmissivity

Burningrate database

FuelsFlame surface



Pag. 22 / 40

44

The solid flame model: predictions and The solid flame model: predictions and validation against experimental validation against experimental

resultsresults



Pag. 23 / 40

SolidSolid flameflame modelsmodels: : predictionspredictions

-50

-30

-10

10

30

50

70

90

110

0 10 20 30 40 50 60

Diameter [m]

SEP

[kW

/m2]

0

100

200

300

400

500

600

700

800

Qra

d [M

W]

TNOSFPENRCHSE

Gasoline, w = 1 m/s

-50

-30

-10

10

30

50

70

90

110

0 10 20 30 40 50 60

Diameter [m]

SEP

[kW

/m2]

0

100

200

300

400

500

600

700

800

Qra

d [M

W]

TNOSFPENRCHSE

Gasoline, w = 5 m/s



Pag. 24 / 40

SolidSolid flameflame modelsmodels: : availableavailable measurementsmeasurements

1.451010-0.85-2.0351010-1.285-6

2.2357.13Hexane

-1.458.610-0.94-1.8658.610

12002.2256.9610302.8857.13Heptane

-0.2753.3731-0.5753.411-0.33-0.6753.810-0.6753.526.5-0.8153.13Crude oil

13800.4354.76013800.4354.730kerosine

13310.453.5-6.2922.31.757101.70.48-1.045710--5-9.6

10001.15-61360.9454.59-6.495.411001.954.83Gasoline

[°C][kW/m2][mm/min][m]Max tempRad at x/D=5x/DBRDFuel

KosekyKoseky, 1989, 1989



Pag. 25 / 40

SolidSolid flameflame modelsmodels: : predictionspredictions vsvs experimentsexperiments(I)(I)

x

0

2

4

6

8

10

12

4 5 6 7 8

x/D

Irrad

iatio

n on

targ

et [k

W/m

2 ]

Exp.SFPENRCHSE

LNGD=6mw=6.6m/s

0

5

10

15

20

25

30

35

40

0.50 0.75 1.00 1.25 1.50

x/D

Irrad

iatio

n on

targ

et [k

W/m

2 ]

Exp.SFPENRCHSE

JP4, D=10mJP4, D=10m

w=4 m/sw=4 m/s

JonhsonJonhson (1992)(1992)



Pag. 26 / 40

SolidSolid flameflame modelsmodels: : predictionspredictions vsvs experimentsexperiments(II)(II)

x

0

1

2

3

4

0 1 2 3 4

Irradianza misurata [kW/m2]

Irrad

ianz

a ca

lcol

ata

[kW

/m2 ]

Gasoline

kerosine

Crude oil

Heptane

Hexane x/D=5x/D=5

D=3~60mD=3~60m

TNO modelTNO model

0

1

2

3

4

0 1 2 3 4


Irrad

ianz

a ca

lcol

ata

[kW

/m2 ]

Gasoline

kerosine

Crude oil

Heptane

Hexane

x/D=5x/D=5

D=3~60mD=3~60m

NRC modelNRC model

0

1

2

3

4

0 1 2 3 4


Irrad

ianz

a ca

lcol

ata

[kW

/m2 ]

Gasoline

kerosine

Crude oil

Heptane

Hexane

x/D=5x/D=5

D=3~60mD=3~60m

SFPE modelSFPE model

0

1

2

3

4

0 1 2 3 4

Meas. irradiation [kW/m2]

Pre

dict

ed ir

radi

atio

n [k

W/m

2 ]

Gasoline

kerosine

Crude oil

Heptane

Hexane

x/D=5x/D=5

D=3~60mD=3~60m

HSE modelHSE model

0.9290.8940.7370.689Correlation coeff. of fitting line

0.9921.0700.8970.448

Slope of fitting line: y = a xy = Q”rad, calcx = Q”rad, mis

HSESFPENRCTNOKoseki data (1989). Model predictions



Pag. 27 / 40

ApplicationsApplications toto the the coolingcooling problemproblem (I)(I)

0

400

800

1200

1600

2000

0 4 8 12 16Dimensionless distance x/R

Rad

iativ

e he

at tr

ansf

er ra

te [k

W]

-20

-15

-10

-5

0

5

10

15

20

Max

imum

hea

t flu

x [k

W/m

2 ]tank top

tank side

Overall

Φ=50Φ=50°°ϑ =0ϑ =0°°

0

500

1000

1500

2000

0 10 20 30 40 50Flame tilt angle [°]

Rad

iativ

e he

at tr

ansf

er ra

te [k

W]

top, x/R = 2top, x/R = 4side x/R = 2side, x/R=4

overall, x/R = 2overall x/R = 4

ϑ ϑ =0=0°°

ϑϑ

yy

XXBBAAΦΦ

wind



Pag. 28 / 40

The The overalloverall water water flowflow raterate can can bebe inferredinferred fromfromenergyenergy balancesbalances, , givengiven the the heatheat fluxflux on on tanktank side side and on and on tanktank top,top, asas a a functionfunction of a of a maximummaximum liquidliquidtemperature temperature toto bebe providedprovided..

The water The water heatheat of of vaporisationvaporisation isis notnot consideredconsidered in in heatheat balancesbalances

∆z

H

mm’’liqliq cpcp, , liqliq ((TTliqliq, , maxmax –– TTliqliq) = ) = ∑∑ ((∆∆zizi QQ””radrad, i, i )) CylindricalCylindrical tankstanks

∑∑∆∆zzii = H= H

mm””liqliq cpcp, , liqliq ((TliqTliq, , maxmax –– TliqTliq) = Q) = Q””radrad, , maxmax vhvh SphericalSpherical tankstanks

QQ””radrad, max , max vhvh = MAX (= MAX (QQ””radrad, v, v , , QQ””radrad, h, h ))

ApplicationsApplications toto the the coolingcooling problemproblem (II)(II)

LocalLocal heatheat transfer transfer coefficientcoefficient and and surfacesurface temperaturestemperatures??



Pag. 29 / 40

55

Some Some resultsresults from CFD analysis, the from CFD analysis, the FDS code by NISTFDS code by NIST



Pag. 30 / 40

The FDS code The FDS code byby NIST (I)NIST (I)

FDSFDS isis a a computationalcomputational fluidfluid dynamicsdynamics (CFD) (CFD) model of model of firefire--drivendriven fluidfluid flowflow, , usingusing the LES the LES ((SmagorinskySmagorinsky) ) approachapproach. The software . The software solvessolvesnumericallynumerically a a formform of the of the NavierNavier--StokesStokesequationsequations appropriate appropriate forfor lowlow--speedspeed, , thermallythermally--drivendriven flowflow withwith anan emphasisemphasis on on smokesmoke and and heatheattransporttransport fromfrom firesfires

The The partialpartial derivativesderivatives of the of the conservationconservationequationsequations are are approximatedapproximated asas finite finite differencesdifferences, , and the and the solutionsolution isis updatedupdated in time on a in time on a threethree--dimensionaldimensional, , rectilinearrectilinear gridgrid. . ThermalThermal radiationradiation isiscomputedcomputed usingusing a finite volume a finite volume techniquetechnique on the on the samesame gridgrid asas the the flowflow solver.solver.



Pag. 31 / 40

The FDS code The FDS code byby NIST (II)NIST (II)

FDS FDS isis largelylargely employedemployed toto studystudycompartmentcompartment firesfires (in (in roomsrooms, , tunnelstunnels etcetc).).

A A reviewreview of of McGrattanMcGrattan (2005) on FDS (2005) on FDS literatureliterature studiesstudies ((aboutabout 170) 170) revealedrevealed thatthatthe majority of the majority of worksworks refersrefers toto firesfires in in enclosuresenclosures and and onlyonly veryvery few of few of themthemconsiderconsider open pool open pool firesfires..

The The reasonreason isis mainlymainly relatedrelated toto the the importanceimportance toto evaluateevaluate the the firefire hazardshazards in in spacesspaces occupiedoccupied byby personspersons..



Pag. 32 / 40

The FDS code The FDS code byby NIST (III)NIST (III)

Some Some paperspapers on FDS on FDS appliedapplied toto tanktank firesfires::

••H.R.H.R. BaumBaum, , K.B.K.B. McGrattanMcGrattan, , SimulationSimulation of Oil of Oil TankTankFiresFires, , IterflamIterflam ConfConf., 1999., 1999

••S. S. HostikkaHostikka, K. B. , K. B. McGrattanMcGrattan and A. and A. HaminsHamins, , Numerical Modeling of Pool Fires Using LES and Finite Numerical Modeling of Pool Fires Using LES and Finite Volume Method for RadiationVolume Method for Radiation, 7th Fire Safety Science , 7th Fire Safety Science Int.Int. SympSymp., 2003., 2003

••F.F. Devia, M. Fossa, Devia, M. Fossa, R. R. Sala*Sala*, , Radiation to the Radiation to the Surroundings from Large Pool Fires over Storage Surroundings from Large Pool Fires over Storage Tanks, Tanks, 6th Int. 6th Int. SympSymp. on Heat Transfer, Beijing, 2004. on Heat Transfer, Beijing, 2004

* Major* Major contributor to contributor to cfdcfd analysisanalysis



Pag. 33 / 40

FDS FDS applicationsapplications at at DiptemDiptem (I)(I)computational grid: 128000 equal computational grid: 128000 equal cells in a computational domain of cells in a computational domain of 320320××2020××200200 m (x, y, z)m (x, y, z)

cell size = 0.25x0.5x1 m;cell size = 0.25x0.5x1 m;

HRRPA=1000kW/ mHRRPA=1000kW/ m22

Soot_yieldSoot_yield= 0.042kg/kg= 0.042kg/kg

MW_FUEL=198.0 (KEROSINE)MW_FUEL=198.0 (KEROSINE)((Ideal stoichiometric coefficients for the reactionNU_O2=21.5NU_O2=21.5NU_CO2=14.0NU_CO2=14.0NU_H2O=15.0NU_H2O=15.0EPUMO2=12700.EPUMO2=12700.CO_YIELD=0.012CO_YIELD=0.012

30m30m

D=24mD=24mh=15mh=15m

D=15mD=15mh=15mh=15m

zz

xx

φ



Pag. 34 / 40

FDS FDS applicationsapplications at at DiptemDiptem (II)(II)

8665.25/2624526.37/24.436600.8461292064211876017.28

HRRPA=2475, rad. Fract.=0.15, Soot=0.10

half domain 320x20x200=12800009

7986.32/34.229508.6/34.849400.8631620144386726016.92

HRRPA=2475, no rad. Fract., Soot=0.10

half domain 320x20x200=12800008

7481.64/9.967643.47/15.820000.859675941915136012.85

HRRPA=1000, no rad.fract.,halfdomain

320x20x200=12800007

8008.38/43.5391010.6/41.860700.7781552964067216016.47

HRRPA=2475, RAD._FRACT.=0.35, half

domain 320x20x200=12800006

7958.53/44.4399010.67/42.261390.7451430124376386016.4half domain

320x20x200=12800005

7807.42/31.534708.72/31.850130.646110146407556606.65half domain

160x20x240=7680004

7287.33/32.434308.29/3147600.663129244428884303.42half domain

160x20x240=7680003

3849.47/33.844207.61/26.243700.30299450442726302.2280x40x150=4800002

17314.44/54.672209.41/33.335300.138983304422116001.1440x32x60=768001

Tmax gas (time ave) (°C)

qave/qmaxtop (kW/m2)

flux radtop (kW)

qave/qmaxside (kW/m2)

flux rad side (kW)

Fire resolution

index

rad loss at the

boundary (kW)

total heat release

(kW)

simulation time (sec)

execution time

(h)GridRun

Parametric analysis



Pag. 35 / 40

FDS FDS applicationsapplications at at DiptemDiptem: : resultsresults

SolidSolid flameflame

0

100

200

300

400

500

600

700

800

-10 0 10 20 30

Distance from tank 1 axis, x (m)Ti

me

aver

age

gas

tem

pera

ture

(°C

)

z'=1 mz'=5 mz'=10 mz'=15 m

z'

x

1 2

•• GGmaxmax, side, side, max irradiation [kW/m, max irradiation [kW/m²²]]1616 (at tank side)(at tank side)

•• overall heat transfer rate [kW]overall heat transfer rate [kW]1950 1950 (tank side)(tank side)850850 (tank top) (tank top)

•• BR, Burning rate [kg/s mBR, Burning rate [kg/s m²²]]0.0230.023

SolidSolid flameflame resultsresults::

0.0550.05511.011.0HSEHSE

0.0670.06713.213.2SFPESFPE

BRBR

[kg/s m[kg/s m²²]]

GGmaxmax, side, side

[[kWkW/m/m22]]



Pag. 36 / 40

Open Open issuesissues and and possiblepossible workwork

CFD SIDECFD SIDESimulatingSimulating the the literatureliterature casescases and compare and compare experimentalexperimental irradiationirradiationand and burningburning rate rate valuesvalues

SimulatingSimulating the the flameflame sagsag

SimulatingSimulating the emissive power the emissive power distributiondistribution on on flameflame extext. . surfacesurface

AssessAssess the FDS the FDS sensitivitysensitivity toto simulationsimulation input input parametersparameters

WallWall temperaturestemperatures on the on the tanktank on on firefire ((tootoo difficultdifficult?)?)

ConclusionsConclusions



Pag. 37 / 40

OpenOpen Issues (SF and cooling)Issues (SF and cooling)FlameFlame temperature temperature alongalong the the flameflame heigthheigthThe The windwind strenghtstrenght and direction and direction toto bebeconsideredconsideredFuelFuel temperature temperature toto bebe consideredconsideredHeatHeat diffusiondiffusion inside inside tanktank and and boilingboiling onsetonsetand/or and/or evaporationevaporation strengthstrengthWater film Water film behaviourbehaviour, , locallocal heatheat transftransf. . coeff. and coeff. and wallwall temperaturestemperatures duringduring liquidliquidcoolingcoolingThe The properproper liquidliquid distributiondistribution alongalong the the tanktanksidesideMistMist vsvs film film coolingcooling toto enhanceenhance radiationradiationprotectionprotection??ShieldsShields toto radiationradiation??

GenovaGenova



Pag. 38 / 40

Fine della presentazioneFine della presentazione

GrazieGrazie delldell’’attentioneattentione



Pag. 39 / 40

... vedrai una città regale, addossata ad una collina alpestre, superba per uomini e mura, il cui solo aspetto la indica signora del mare.(Francesco Petrarca)



Pag. 40 / 40

radiation in case of fire in tank farms

Documents

thermal energy

solid flame modelfire

solid flame model4

tank cooling

thermal radiation

production management

mathematical modeling

area of mathematical