Experimental investigation and CFD simulation of organic peroxide pool fires (TBPB and TBPEH) [Elektronische Ressource] / von Kirti Bhushan Mishra

Description

Experimental investigation and CFDsimulation of organic peroxide pool fires(TBPB and TBPEH)Von der Fakult¨at fur¨ Ingenieurwissenschaften, Abteilung Maschinenbau undVerfahrenstechnik derUniversit¨at Duisburg-Essenzur Erlangung des akademischen GradeseinesDoktors der IngenieurwissenschaftenDr.-Ing.genehmigte DissertationvonM. Tech. Kirti Bhushan Mishraaus Cuttack, IndienGutachter: Univ.-Prof. Dr. rer. nat. Christof Schulz: Univ.-Prof. Dr. rer. nat. Axel Sch¨onbucherVorsitzender: Univ.-Prof. Dr.-Ing. Johannes WortbergTag der mundlic¨ hen Prufung:¨ 12. Mai 2010AcknowledgementsThis PhD thesis has been carried out in the context of a doctoral programme during mywork as a research assistant in the working group on “Explosive Substances of ChemicalIndustries”, at the BAM Federal Institute for Materials Research and Testing.I express my deep sense of gratitude to Prof. Dr. rer. nat. Axel Schon¨ bucher, De-partment of Chemical Engineering I, University of Duisburg-Essen, campus Essen, forenabling this opportunity to work under his kind supervision. I am very thankful forhis continuous technical guidance and scientific discussions. A very sincere thank anddeep appreciation to Prof. Dr. rer. nat. Christof Schulz, Institute for Combustion andGas Dynamics, Department of Mechanical Engineering, University of Duisburg- Essenfor his expert suggestions and comments on different topics of interest.I would like to thank especially Prof. Dr. rer. nat.

Informations

• Publié par: universitat_duisburg-essen
• Publié le: 01 janvier 2010
• Nombre de lectures: 45
• Langue: English
• Poids de l'ouvrage: 17 Mo

Extrait

ExperimentalinvestigationandCFD
simulationoforganicperoxidepoolfires
(TBPBandTBPEH)

VonderFakult¨atf¨urIngenieurwissenschaften,AbteilungMaschinenbauund
Verfahrenstechnikder

Universit¨atDuisburg-Essen

zurErlangungdesakademischenGrades
einesDoktorsderIngenieurwissenschaften

-Ing..Dr

tionDissertaegenehmigt

vno

M.Tech.KirtiBhushanMishra
Indienk,Cuttacaus

Gutachter:Univ.-Prof.Dr.rer.nat.ChristofSchulz
:Univ.-Prof.Dr.rer.nat.AxelSch¨onbucher
Vorsitzender:Univ.-Prof.Dr.-Ing.JohannesWortberg

Tagderm¨undlichenPr¨ufung:12.Mai2010

Acknowledgements

ThisPhDthesishasbeencarriedoutinthecontextofadoctoralprogrammeduringmy
workasaresearchassistantintheworkinggroupon“ExplosiveSubstancesofChemical
Industries”,attheBAMFederalInstituteforMaterialsResearchandTesting.

IexpressmydeepsenseofgratitudetoProf.Dr.rer.nat.AxelSch¨onbucher,De-
partmentofChemicalEngineeringI,UniversityofDuisburg-Essen,campusEssen,for
enablingthisopportunitytoworkunderhiskindsupervision.Iamverythankfulfor
hiscontinuoustechnicalguidanceandscientificdiscussions.Averysincerethankand
deepappreciationtoProf.Dr.rer.nat.ChristofSchulz,InstituteforCombustionand
GasDynamics,DepartmentofMechanicalEngineering,UniversityofDuisburg-Essen
forhisexpertsuggestionsandcommentsondifferenttopicsofinterest.

IwouldliketothankespeciallyProf.Dr.rer.nat.Klaus-DieterWehrstedt,Headof
theDivisionII.2“ReactiveSubstancesandSystems”atBAM.Iamverygratefulfor
hisexpertsuggestions,numerousdiscussionsonvarioustopicsandhispurposefulway
ofworkingwhichalwaysmotivatedandsupportedme.

IwouldalsoliketothankDr.rer.nat.HeikeMichael-Schulz,HeadoftheWork-
ingGroupII.23“ExplosiveSubstancesofChemicalIndustries”atBAMforproviding
excellentsupportandco-operationforconductingtheexperiments.

Also,IwishtothankDr.-Ing.MichaelRudolphandDr.rer.nat.MarcusMalowfrom
BAMII.2andDr.-Ing.AnjaHofmannandDr.rer.nat.SimoneKru¨gerfromBAM
VII.3forthefruitfuldiscussionsandtechnicalknowhows,particularlyforexperimental
work.MyspecialthankstoallcolleaguesDipl.-Ing.GerhardReinhardZemke,Dipl.-
Ing.JochenKebben,Dipl.-Ing.KimStattaus,Mr.Klaus-DieterNicolaus,Ms.Bianca
Fourier,Dipl.-Ing.Kai-UweZiener,Dipl.-Ing.MartinBeckmannKlugeandDipl.-Ing.
ReinholdWendlerofBAMforco-operationandgreatassistanceintheimplementation
ofexperimentalstudies.Mr.MichaelBulinisthankfullyacknowledgedforthecluster
administrationofBAMIIforcarryingoutsimulations.IamverythankfultoDr.rer.
nat.IrisVela,Dipl.-Phys.PeterSudhoffandDr.rer.nat.MarkusGawlowskifromthe
InstituteofChemicalEngineeringI,UniversityofDuisburg-Essen,Essencampus,for
theexcellentcooperation,friendlysupportandassistanceincomputationalwork.

Iamalsoverythankfultojoshijiandashwinibhabhiforthearrangementofrefreshing
tea-breaksandthecompaniesofpurvaandmaololanduringthelunchtime.

iii

ShriNarsinghaDevayNamah

Dedicatedtomyparents(ShriNarayanPrasadMishraand
ShrimatiPriyambadaMishra)andmylovingbrothers(ShriVibhuti
BhushanMishra,ShriShashiBhushanMishra,ShriRaviBhushan
MishraandShriChandraBhushanMishra)andtheirfamiliesand
toallmybelovedonesthecompanyofwhomimissedalot..........

v

ABSTRACT

Timeaveragedmassburningrate(m˙f),flamelength(H),temperature(T),irradi-
ance(E)andsurfaceemissivepower(SEP)ofTBPB(tert-butylperoxybenzoate)and
TBPEH(tert-butylperoxy-2-ethylhexanoate)poolfiresaremeasuredforsixpooldi-
ameters(d=0.059m,0.107m,0.18m,0.5m,1mand3.4m)atBAMinhouseand
outsidetestfacility.
Themeasuredheatsofcombustion(–Δhc)ofTBPBandTBPEHare30113kJ/kgand
34455kJ/kgandthespecificheatcapacitiesatconstantpressure(cp)are1.8kJ/(kgK)
and2.1kJ/(kgK)respectively.
Themeasuredm˙fofTBPBandTBPEHpoolfiresareintherangeof0.37kg/(m2s)≤
m˙f≤0.83kg/(m2s)andshowlittledependenceonthepooldiameterd,andarefour
tosixtytimeshigher(ford=1m)thanthatofhydrocarbonpoolfires.Itisshown
thatthemassburningratesoftheinvestigatedorganicperoxidescanberepresented
asanexponentialfunctionoftheself-acceleratingdecompositiontemperature(SADT).
LowSADTimpliesthattheorganicperoxidepoolfiresburnatamuchhigherm˙fthan
hydrocarbonpoolfires.
FuelFroudenumbers(Frf)ofTBPBandTBPEHare5to100times(dependingond)
higherthanforhydrocarbonpoolfires.DuetohigherFrftheHofTBPBandTBPEH
(measuredwithaS-VHSVideocamera)arefoundtobetwotimeslarger(d=1m)than
correspondingpoolfiresofhydrocarbons.Heskestadsflamelengthcorrelationpredicts
thedH(d=3.4m)ofTBPBandTBPEHpoolfiresmuchbetterthanThomasandFay
.scorrelationThemeasuredtimeaveragedflametemperaturesT(d=3.4m)forTBPBandTBPEH
poolfiresareintherangeof1400K≤T≤1500Kandare200Kto300Khigherthan
forJP-4,keroseneandgasoline.
TheirradiancesoftheTBPBandTBPEHpoolfiresmeasuredbyradiometersareE
(Δy/d=0.3)=45kW/m2andE=98kW/m2whicharetwototentimeshigherin
comparisontothecorrespondingn-pentane,supergasolineanddieselpoolfires.Sothe
thermalsafetydistancesfororganicperoxidepoolfiresarelargerbyafactorfourin
comparisontothehydrocarbonpoolfires.
AninfraredthermographysystemisusedforthedeterminationofSEPofTBPBand
TBPEHpoolfires.ThevaluesofsurfaceemissivepowerforTBPBandTBPEHare
SEP(d=3.4m)=196kW/m2andSEP=258kW/m2andthustheSEParebya
factorofapproximatelytwohigherthanforhydrocarbonpoolfires.
Aself-sustainedpulsatingdH(’W’-Effect)isfoundinTBPBpoolflamesandisfurther
analysedtoexplainthereasonofoccuranceonthebasisofchemicalstructureofthefuel
anddiscontinuousheatfluxbackfromflametotheliquidpool.

CFDsimulationsofTBPBandTBPEHpoolfiresatd=0.18m,0.5m,1m,3.4mand8
marecarriedoutusingtheUnsteadyReynoldsAveragedNavierStokes(URANS)equa-
tions.Thethree-dimensionalgeometrieshavebeendiscritizedwithunstructuredhybrid
grids,withthenumberofcellsintherangeof1million.Dependingonthegridresolu-
tionandthepooldiametertimestepsof0.0001s≤Δt≤0.01sfortheCFDsimulations
areused.ForsolvingthediscritizedequationsafinitevolumebasedimplicitsolverAN-
SYSCFXhasbeenused.Formodellingthecombustion,stoichiometriccombustionfor
bothperoxidesareassumed.Thetemperaturedependenceofthereactionratehasbeen
determinedbytheArrheniusapproach.Formodellingthecombustioneddydissipation
concept(EDC)modelhasbeenused.Forturbulencebuoyancymodifiedk-andSAS
(ScaleAdaptiveSimulation)turbulencemodelsareused.Forthethermalradiationand
sootmassfractiondiscretetransferradiationmodelandMagnussonsootmodelhave
beenused.
Anewmethodissuggestedforthepredictionofmassburningrate(m˙f)byCFDsimula-
tion.Bothperoxidepoolfiresshowapproximatelyconstantmassburningrateindepen-
dentofdwhereasm˙fofTBPEHareunderpredictedatthebeginningbutshowrelatively
goodagreementwithmeasurementsforlargepooldiameters(d=1m).IncaseofTBPB
theCFDsimulationoverpredictsthemassburningratem˙fofsmallTBPBpoolfires
andshowsacontinuousdecreasewithd.CFDpredictstheflamelengthHclosetothe
measureddataprovidedthattheconstantsinThomasequationaremodified.
TheCFDpredictedtimeaveragedsurfaceemissionflametemperaturesofTBPBand
TBPEHpoolfires(d=3.4m,1437Kand1542K)areingoodagreementwiththe
measuredtimeaveragedflametemperatures.
TheCFDpredictedSEPforTBPBandTBPEHpoolfires(d=3.4m,217kW/m2and
288kW/m2)arealsoinagreementwiththemeasuredvalues.FromtheCFDpredicted
irradianceECFDitispossibletodeterminethethermalsafetydistancesfromlargepool
firesofhydrocarbonsandorganicperoxides.

Contents

ixiiatureNomenclxvsrLetteGreekxviisIndicexixionsAbbreviatxxianeousMiscell1ductiontroIn12TheoreticalBackground5
2.1Introduction...................................5
2.2Dynamicsofpoolfires.............................5
2.2.1Massburningrate...........................8
2.2.1.1TheoryofburningrateaccordingtoHertzberg......12
2.2.1.2Effectoflipheight,thicknessandpanmaterial......13
2.2.2Flamelength..............................13
2.2.2.1FlamelengthmodelaccordingtoThomas.........16
2.2.2.2FlamelengthmodelaccordingtoSteward.........17
2.2.2.3FlamelengthmodelaccordingtoMcCaffrey.......17
2.2.2.4FlamelengthmodelaccordingtoMoorhouse.......18
2.2.2.5FlamelengthmodelaccordingtoHeskestad........18
2.2.2.6FlamelengthmodelaccordingtoFay...........19
2.2.2.7Effectofunsteadiness....................21
2.2.3Flametemperatureandflowvelocity.................21
2.2.4Adiabaticflametemperature.....................25
2.2.5Thermalradiation...........................25
2.2.5.1Pointsourcemodel.....................25
2.2.5.2Conventionalandmodifiedsolidflameradiationmodel.27
2.2.5.3Viewfactors.........................31
2.2.5.4Atmosphericabsorption...................33
2.2.6OrganisedStructuresRadiationModels(OSRAMOII,OSRAMO
III)....................................33
2.3Organicperoxides...............................34
2.3.1SelfAcceleratingDecompositionTemperatureoforganicperoxides37
2.3.2Fireandexplosionhazardsoforganicperoxides...........38

ix

xtstenCon2.4Modellingandsimulationofpoolfires....................39
3ExperimentalInvestigations41
3.1Descriptionofmeasuringinstruments.....................41
3.1.1DynamicDifferentialCalorimetry(DDC)..............41
3.1.2Thermocouples.............................43
3.1.3Thermographiccamera........................44
3.1.4Radiometers..............................45
3.2Experimentalset-upsforsmallandlargescalefiretests..........46
3.2.1Construction..............................46
3.2.2Fuels...................................47
3.2.3Massburningrate...........................48
3.2.4Flamelength..............................48
3.2.5Flametemperature...........................48
3.2.6Surfaceemissivepower