火災(zāi)動力學(xué)FD08a-滅火動力學(xué)

科威特油田大火的四種滅火方法（水流、大風(fēng)、立管、爆炸）可樂滅火咋回事？滅火試驗的數(shù)據(jù)庫；噴淋頭設(shè)備的可靠性不同滅火劑的的滅火模型；噴淋頭與煙氣的互動；滅火系統(tǒng)對風(fēng)險的影響；氣相滅火系統(tǒng)的系統(tǒng)安全因子與容限。滅火領(lǐng)域的挑戰(zhàn)提綱ReviewtheexistingsuppressiontheoryDropletevaporationtheoryDistributionofdropletsRoleofwateradditivesHottopicsinfiresuppression表面冷卻(質(zhì)量燃燒率問題或火點理論)氣相惰化和稀釋（物理吸熱過程）氣相剪切過程（流動剪切和注定時間）化學(xué)協(xié)同效應(yīng)（包括膠囊在內(nèi)的化學(xué)效果）；物理隔離（覆蓋、膨脹、密封等）滅火的機理2025/6/26最簡單的滅火理論火災(zāi)三角形利用惰性氣體的吸熱能力，增加反應(yīng)系統(tǒng)的惰性，從而降低燃燒溫度，達到反應(yīng)不能維持的程度。吸熱滅火2025/6/26化學(xué)協(xié)同滅火Heatofcomb.Fuel@InitialstateFlame@AFTProducts@FinalstateEnergyabsorbingEnergyreleasingFuel/oxygen/diluentNewAFT速度滅火與表面吸熱Blow-out/blow-off/Fade-out9物理隔離滅火理論很難統(tǒng)一HeatandmasstransferSpalding’sB-numbertheory(Rasbash’sfirepointtheory)+dropletdynamicsFluidmechanics&chemistryDamkoehlernumbertheoryCombustion/reactionchemicalequilibrium(Semenovtheory)11DamkoehlerNumbertheoryNavier-Stokesequationcanberewriteas12WallquenchingFlowstretchingDilutionAbsorptionChemicalinhibition速度滅火杯狀燃燒器Cupburner惰化效果Inertingeffect吸熱反應(yīng)Reactingeffect壁面冷卻WallQuenching/Cooling加熱效果Heating

effect速度效果Velocityeffect惰化的熱理論DiffusionflametheorypremixedflametheoryThermaltheoryinitsfinalform沒有溫度修正的最小滅火濃度.

有溫度修正的最小惰化濃度.

吸熱量的分解ArgonArgoniteInergenNitrogenCO2Inerting0.6320.8120.8980.9921.615Reacting1.01.01.01.01.089Heatloss1.2821.2821.2821.2821.282氮氣惰化的LOC濃度二氧化碳惰化的LOC濃度.

燃料的可滅性指數(shù)21燃料滅火濃度的預(yù)報哈龍的作用：協(xié)同效應(yīng)篩選滅火劑的有效性化學(xué)滅火的協(xié)同效應(yīng)協(xié)同效應(yīng)2025/6/26協(xié)同指數(shù)Lott,J.L.,Christian,S.D.,Sliepcevich,C.M.,Tucker,E.E.,SynergismbetweenChemicalandphysicalfire-suppressantagents,FireTechnology,Vol32,No.3,199627FAAsuppressionexperiments28氣體滅火的特殊問題2025/6/26封閉空間的滅火方式：全淹沒開放空間的滅火方式：局部作用32兩種滅火劑的沖突Early1990s,DODfoundC2F5H(HFC125)andC3F7H(HFC-227ea).HFC-227ea七氟丙烷的物理特征不太好，失去市場。HFC125的毒性不太好，剛開始不突出。電氣火災(zāi)的困境聚相滅火的特殊問題聚相滅火機理主要作用冷卻燃料床隔離燃料次要作用稀釋，增加閃點降低輻射能力35火點理論Themassburningrateequation@firepointThecriticalmassfluxatextinctionisabalanceUsingSpalding’sB-numbertheory,thefirepointequationis36冷卻劑的作用Thecriticalfractionoftheenergyreleasewhichneedstobelosttocauseextinction.Foranewextinguishingagentintroduced,37ThermalcapacityDilutionChemicalInhibitionBeyler,C.,AUnifiedModeloffireSuppression,JFPE,4(1),1992,pp5-16液滴動力學(xué)38Fig.2.Temporalevolutionofradiusofevaporatingwaterdropletindrystillair.Solidline–presentmodel,dashedline–non-conjugatemodel(Elperin&Krasovitov,2003),circles–experimentaldata(Ranz&Marshall,1952).DropletDynamics深層A類火災(zāi)的挑戰(zhàn)擴散性能Diffusivity黏著性能Adhesioncapability(CAFS)水合反應(yīng)Reactivitywithwater(ClassDfirechallenge)阻燃添加劑Retardancywithwateradditives水的粘性Limitationofwater(viscosity)浸潤水（Wettingwater），添加某些增粘劑，降低水的表面張力，可以達到深入A類燃料內(nèi)部，浸潤燃料的效果。通常適用于某些不利水分滲透的材料，如塑料、合成纖維、橡膠等。粘性水（Thickeningwater），在水中添加增稠劑，提高誰的水的粘度，增加水在燃料表面，特別是垂直表面上的附著力，防止水分的流失，達到節(jié)水的目的。野火中飛機灑水作業(yè)，需要使用粘性水，以避免水分的不必要流失。阻燃水（Retardingwater），通過添加堿金屬鹽火有機金屬鹽，在A類火災(zāi)撲救中提高抗復(fù)燃性能，可以達到事半功倍的效果。泡沫水（Foamingwater），通過添加促進發(fā)泡的發(fā)泡濃縮液，產(chǎn)生蛋白泡沫，提高泡沫的耐性和抗輻射能力，有利于B類火災(zāi)的撲滅。霧化水（Watermist），通過化學(xué)方法生成細水霧，生成微型乳化霧，達到窒息火焰的目的。主要用于油類（B類）和電氣（C類）火災(zāi)，不適用于A類火災(zāi)，因為吸熱能力不足。乳化水（Emulsifyingwater），添加乳化劑，與水混合后以霧狀噴射。利用乳化劑的憎水基團來撲滅閃點較高的油類火災(zāi)，也適用于油類泄漏處理。消防水的改性處理如何改變粘性PropertiesDecreaseviscosityIncreaseviscositypurposeIncreasefluidityMakefluidsstickyNameWettingagentThickeningagentwaterthinnerthickerSurfacetensionreduceIncreaseSurfaceareaincreasedecreasecoveragemorelessFrictionlosssmallerlargerPenetrationIncreasedecreaseHeat-absorbingcapacitydecreaseincreasemixingFar-awayNohose,atpumpDropletsFinedropletsfortotalfloodingLargerdropletsforbetterpenetrationAdherespreadadhereApplicationMoppingupsmolderingfire/finalcleanupInitialattackandpretreatmentoffuel42添加劑添加劑類型目的添加劑類別商業(yè)產(chǎn)品滅火類型主要機理浸潤水降低表面張力洗衣粉濕水Aa增稠劑（包括乳化劑）Thickeningagents(includingEmulsification)增加表面張力Gums,methylcellulose,bentonitetypeclaysGel,slurryABa阻燃劑Retardingagents表面阻燃處理堿金屬鹽碳酸鉀Aa/d發(fā)泡劑Foamingagents促進發(fā)泡AFFF,ARFF,PFFFetc.合成泡沫Ba/e霧化劑Mistingagents通過化學(xué)辦法生成細水霧低沸點燃料微型乳化霧BCc協(xié)同劑Synergyagents與細水霧發(fā)生協(xié)同作用1-bromo-3,3,3-trifluoropropene(BTP)

BCc/d膠囊劑Encapsulatingagents提升閃點

F-500ABDc/d滅火器常識A類固體火災(zāi)ClassAfiresinvolveitemssuchas:OrdinarywoodRubberHouseholdrubbishNaturalvegetationWaterismostcommonextinguishingagent.B類油池火災(zāi)ClassBfiresinvolveitemssuchas:FlammableliquidsandgasesOilGreaseTarSomeplasticsSeveralagentscanbeused.FlammableandCombustibleLiquidsandgasesC類電氣火災(zāi)ClassCfiresinvolveenergizedelectricalequipmentsuchas:BuildingwiringCircuitbreakersTransformersPowertoolsRequireagentsthatwillnotconductelectricityD類粉塵火災(zāi)ClassDfiresinvolvecombustiblemetalssuchas:MagnesiumSodiumLithiumPotassiumViolentreactionstowaterandotheragentscanoccur.K類廚房火災(zāi)NewclassificationduetocookingtrendsInvolvecombustiblecookingoilsandfatsSomerestaurantsstilluseClassBextinguishers.滅火器的圖形標(biāo)識PictorialsystemOnlyA,B,CandKclassesoffire,nopictorialsymbolforClassD,combustiblemetalfiresLettersystem圖形符號滅火器的選擇矩陣如何給滅火器分級UL711,StandardForRatingandFireTestingFireExtinguishersRatingcriteriaIntendeduse(fireclass)FirefightingcapabilityFireFightingcapabilityVolumeanddurationofagentdischargeRangeofdischargeHydrostatictestingoftheagentvesselanddischargehose滅火器分級的測試方法ClassA

Woodcribtest Woodpaneltest ExcelsiortestClassB-2inch(50mm)layerofflammableliquidClassC–non-conductivitytestClassD Magnesiumfiretests SodiumAndPotassiumFireTestsClassK-ULStandard300CribTest–FirLumberwithmoisturecontentbtwn9&13%.Nominaldimensionsare2X2inches,largertests2X4inches,heightbasedonratingtobeachieved.Class1-Ato4-Apreburnof8-10minutesorunitlstickmembersinthetopthreerowshavebeenreducedto?to1inchdiameters.Above4-Aratings,dimensionsforpre-burnare?to2/3theoriginaldimension.Timeis6-7minutes.Startfrom6feetaway,durationofdischargeshouldbe13secondsorgreaterfor2-AratingA類木塊堆測試ClassB–2inchdeeplayerofn-heptaneinan8inchdeeppan.Areaofthefuelandfiremustcorrespondto1squarefoot.Preburnfor60seconds.ExtinguishfireevaluatingTimeofextinguisherapplication,timeforexting.Orcontrol,timeagentdischargeended.B類油池火災(zāi)測試C類火災(zāi)測試ClassC–two12X12inchcoppersheets10inchesbetweennozzleandtargetplate.Electricalpotentialbetweenthetargetandthenozzleis100,000volts.Twodischargesfirstof20secondsandsecondof15secondsagainstthetarget,withnovisualeffectsClassD–Magnesium–AreaFireTest PallettransferFireTest PreMixFireTest CastingFireTestSodium,PotassiumandNaKAlloys SpillfireTest PanFireTestClassK–FryertestLookingfor -extinguishoffire -preventionofre-ignitionfor20minutesoruntiltemperaturedecreasestoaspecifiedtemp -causenosplashingofflammableoiloutsidethefryer其他測試手段滅火劑種類WaterAntifreezeagentsCarbondioxide(CO2)Aqueousfilmformingfoam(AFFF)Filmformingfluoroprotein(FFFP)ClassDdrypowders:NA-X;Met-L-X;Lith-XHalogenatedagentsHalon1301/1202HalonreplacementagentsHalotron,FM200,FE25DrychemicalagentsSodiumBicarbonate-NaHCO3SodiumChloride-NaClPotassiumBicarbonate-NHCO3PotassiumChloride-KCLPotassiumSulfide–K2SO4Urea-PotassiumBicarbonate–NH2CONH2+KHCO3Multipurpose:monoammoniumphosphate清水滅火器Efficient,plentiful,andinexpensiveConvertsfromliquidtosteam,absorbingheatintheprocessEffectiveonClassAfiresLesseffectiveordangerousonotherclassesLoaded-streamextinguishersusedinareassubjecttofreezingWettingagentscanbeaddedforpenetration.干化學(xué)滅火器(1of3)StreamoffinelygroundparticlesDifferenttypesofcompoundsareused.Extinguishintwoways:InterruptschemicalchainreactionAbsorbslargequantitiesofheat7干化學(xué)滅火器(2of3)SeveraladvantagesoverwaterextinguishersOrdinary:suitableforClassBandCfiresMultipurpose:ratedforClassA,B,andCfires干化學(xué)滅火器(3of3)Additivespreventpackingandcaking.Disadvantage:chemicalsarecorrosive.Primarycompoundsusedindrychemicalextinguishers:SodiumbicarbonatePotassiumbicarbonateUrea-basedpotassiumcarbonatePotassiumchlorideAmmoniumphosphate二氧化碳滅火器(1of2)1.5timesheavierthanairFormsadenseclouddisplacingairsurroundingthefuelInterruptscombustionbyReducingtheoxygenDisruptsliquidfuel’sabilitytovaporize二氧化碳滅火器(2of2)StoredunderpressureasaliquidRatedforClassBandCfiresonlyLimitationsinclude:HeavierthansimilarlyratedextinguishersShortdischargerangeDoesnotperformwellbelow0oForinwindSuffocationhazardinconfinedspacesNotsuitableforpressurizedfuelorcookinggreasefires泡沫滅火器FoamWater-basedfoamconcentratesolutionNozzlesintroduceairtoformfoamblanket.UseonClassAorBfiresAdditivesdependoncompatibilitywithfuels.SomefoamsapprovedforpolarsolventsNotsuitableforClassCfiresCannotbestoredorusedatfreezingtemperatures濕化學(xué)滅火器OnlyagenttomeetClassKfireratingChemicalsappliedaswatersolutionsFormulatedforuseincommercialkitchensSaponificationturnsoilsandfatstosoaporfoam.Creates