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ARTICLE INFO
Artic/ehistory:
Received14August205 Receivedinrevisedform4September2012 Acepted21September2012
Keywords: Gasexplosion Gasolinevapor Leisureboat Linkedcompartments FlamableiImit Schlieren
1.Introduction
Sincetheflashpointofgasolineislow，itmixeswithaireasilyat roomtemperatureandformsaflammablevapor(Drysdale，1998; Bond，191).Althoughgasolineisafamiliarfuel，itcancauseserious acidentsifhandledinapropriately.Recently，injapan，self司 help gasstationshaveproliferated，andpeoplehavetendedtobecasual abouthandlinggasolinedespitetheexplosionrisk.Ifgasolineaci- dentalyleaksfromthefueltankofashiporanautomobile，itmay runtoanencIosedspaceintheshiporindoorautoparkingfacility. Spiledgasolineevaporatesimmediatelyandmaydifusetoother roomsthroughdoors，cIearancesandventilationopenings.When gasolinevaporaccumulatestotheflammablelimitinanencIosed roomandisignitedbysuchheatsourcesassparks，pilotflames，cig- aretesorstaticelectricity，anexplosionmayhappenimmediately intheencIosedroomandmaypropagatetolinkedrooms.
Thetransmisionofanexplosionthroughachanneloragap fromaveseltoanotherveselhasbeeninvestigated(Fairweather eta，.l 1999;Razusetal.，2003;PonizyandLeyer，1999;Wolfhard and Bruszak，1960; Girard et a，.l 1986; Starke and Roth，1989;
*Corespondingautho.rTel.:+81975526921;fax:+81975526975. E-mail日dres:konishi@oita-c.tac.jp(T.Konishi).
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Experimentalanalysisoftheexplosionmechanismofgasolinevaporina smalleisureboat
TadashiKonishiaぺAkihikoItob，YujiKudoc，YoshiyukiIchinomiyad，NaomasaKamimurad
aDep日rtmentofMechanicロ1Enginering，DitaNロtion日1ColegeofTec/mology，Mala16，Di臼 870-0152，]ロpan bFIロcultyofScienceandTechnology，HirosakiUniversity，Bunkyo-cyo，Hiros日la036-8561，]apan CF日，cultyofEnginering，HachinoheInstituteofTechnolo幻" Hachinohe，031-8501，]apan dSaekiMロrineSafetyStl日訂on，S日iki，Dit日 876-081，]apan
ABSTRACT
Themechanismthatproducesanexplosionfromthevaporofgasolineinasmaleisureboatiselucidated byusingasmal-scalecombustionchamberandamock-upboat.Thestudyrevealsthattheexplosionis causedby:(i)leakageofgasolinevaporfromafueltank，(i)difusionandacumulationofgasolinevapor inabaterycompartment，and(i)ignitionofpremixedgasandflamepropagationbetweenlinkedcom- partments.Theleakageofgasolinevaporfromthefueltankissucesfulyvisualizedbytheschlieren method.Theprocesofdifusionofthegasolinevaporfromthefuel-tankcompartmenttothebatery compartmentisdemonstratedinthemock-upboat.Aflamablemixtureofgasolinevaporinthebatery compartmenthasbeenestimatedtobemaintainedfromthe1.7thdaytothe175thdayafterplacement ofthefiledandleakingfueltank.Ignitionofthepremixedgasandtheflamepropagationprocesarever- ifiedbyusingthesmal-scalecombustionchamber.Ahigh-spedcameravisualizesthebehaviorsofigni- tionandflamepropagationduringthecourseofexplosionsinlinkedcompartments.Finaly，inorderto confirmthepresumedmechanism，areproducibilitytestiscariedoutbyusingthemock-upboattosim- ulatethesituationintheactualacident.Theactualexplosionissucesfulyreproducedinthemock-up boa.t
。2012ElsevierLtd.Alrightsreserved.
Philips，1963; Singh，1994; Maremonti et a，.l 1999; Bradley， 201).WhenanexplosionpropagatesbetweeniInkedcompart- ments，aphenomenoncaled“presurepiling"ocurs，character- ized by an increase in the initial presure and atmospheric densityinthesecondcompartment.Manyresearchershaveinves- tigatedtheefectsofthegeometryanddimensionsofconnected compartments on presure piling. Handbook (2002) reported explosionandflameacelerationduetoflame-inducedinstabilities inlargeventedboxstructures.
Unfortunately，previousreportsdonotdealwithlargeormid- dle-scaleexplosionspropagatingbetweeniInkedcompartments. This paper describes an experimental analysis of the explosion mechanismwhengasolinevaporleaksinsideasma1lleisureboat withseverallinkedcompartments.
Toelucidatetheexplosionmechanism，thestudyobjectivesare: (i)tovisualizetheleakageofgasolineorgasolinevaporfromthe fueltank，(i)toexplainthedifusionofgasolinevaporfromaport- side location such as a fuel.tank storage compartment to a starboardlocationsuchasabaterycompartment，andtodeter- minethetimerequiredtoreachtheflammablelimitofgasoline vaporinthestarboardstoragecompartment，(ii)toconfirmthe potentialforignitionofgasolinevaporbyasparkfromabatery， andtoexplaintheflamepropagationprocesfromthestarboard