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(c)
(d2)
唱
T=(3P12R)(NAA2(NB-NAJλ2・NAAiNB-NA)λl2 (1)
Where，n=refractiveindex，T=temperature，C=molefractionof speciesi，P=presure，N=molarrefractivityofspeciesi，R=universal gasconstant;subscripts:入t=wavelengthoflaserbeam1(48nmAト ionlaser-beam)，andA2=wavelengthoflaserbeam2(632nmHe-Ne laser-beam)，a=air，f=fuel.
D Whologramscontainhologramsoftwodiferentwavelengths thatneedtobeseparated. WefirstrecordedtheD Whologramsona holographicplate.Then，duringtheprintingproces，twodiferent白1- terswereusedtoseparatethetwoholograms. Thesefiltershavenar- rowband-paswidths，eachpasingthewavelengthmatchtothatofits respectivelaser-beam.
RESULTSANDDlSCUSSION PTLSResults
Figure3showsaschematicofthepulsatingflamespreadconsist-
ingofsixdiferentsteps.Figure4showsthegasphaseSTTandliquid
phasePTLS(representative)photographsforfourdiferentsteps(a，b，
c，anddt). Figure5shows2・Dflowvectordiagramsforsteps(a，b，c，
andd). Step(a)isthebeginingofthecycleofpulsationandthe 1
tocompletethecycle. Theschematicofstep(dt)，notshowninthe originaldiagrampublishedin191[Ito，Masada，andSaito，191]，was addedbecauseithelpsusunderstandtheprocesofflamepulsation beter.
(ル 1)λ1(NB-NA)λ2-(n-1)λiNB-NA)入I c = ( n -1)λ2NAλ r(n-1)λ1N A入2
(n-1)λl(NB四NA)~2-(n-I)AiNB四 NAJ入l ThesymbolsNintheaboveequationsaredefinedas:
...
(2)
(3)
NA=NAλ+C(NBA-NAλ)
Buoyancy凶in凶d山uce吋dflow一+¥γ:、¥:い Gas
Flame
'，~，> ::.jJJ[
(a)
l-72議採 J ぢ 轡C
( d l ) T h e m - f t y戸 で~繋餐吾妻注予告三
fJ4
プ略喝さ長~
山吋、〉
procesmovesontosteps(b)，(c)，(d)，(d)，(e)，andreturnstostep(a) t2
...v雄三
Atstep(a)theflamespreadsslowlytotheleftandtheremaybea
Circul
ur...ω -:7マ塑?マ
buoyancy-inducedairflowoverthefuelsurfaceaheadoftheflame. Thereisahotzoneformedinliquidphaseneartheflame'sleading edge，butnosurfacetensionflowwasformedintheliquidphase. At step(b)theflamespreadsfasterthanthestep(a)generatingasurface- tensionflowwhichflowsinthesamedirectionastheflame.1nthegas phase，thereisabuoyancy-inducedairflowwhichmovesagainstthe flamespreaddirection. Thebuoyancy-inducedairflowandtheliquid surface-tensionflowdirectagainsteachothercreatingasmalcircula- tioninthegasphasejustaheadoftheflameleadingedgecreatinga flamablegas-airmixtureovertheextendedupstreamdirection.Thus， theaircirculationregionalsoincreaseditsdiameterintheupstream directionpreparingfora臼st"jump"flamespread(stepd)toocur. Becauseofasudenincreaseoftheflamespreadrateatstep(dt)，a thermalexpansionoftheairtakesplaceinthecirculationzonedestroy- ingthecirculationandcreatinganewairflowconcurenttotheflame spread.Thisconcurentairflowaceleratestheliquidsurface-tension flow，flamespreadsalongwiththeflow，andeventualytheflameal- moststopsaftertheflameleadingedgereachestheheadoftheliquid flow(stepd2). Afewsecondslater，step(e)takesplace. Thenthe procesreturnedtostep(a)completingthewholeproces(lto，Masuda， andSaito，191，providesfiveinterferogramscorespondingtostepsa， b，Cd2ande).
STTResults Fourdiferentsmokestreakphotographsforsteps(a，b，c，anddt)
areshowninFigs.4(a)，(b)，(c)and(dt). Figure4(a)，wheretheflame spreadra旬 is1.2cmJs，showsnoliquidconvectiveandsurface-tension flowsandthereseemstobeasmalflame-inducedairflowwhichwas clearbyvisualobservation，butnotc1earintheSTTphotograph.Fig- ure4(b)，wheretheflamespreadrateis2.0cmJs，showsbothasmal circulation(5m minlengthand2m minheightanditscirculationcen- terislocatedaproximately5m mfromtheflame1eadingedge)and surface-tensionflow. Figure4(c)，wheretheflamespreadrateis4.6
)wdγ
句協~可~云霊会~
Figure3 Schematicsofthepulsatingflamespread.
，、J
J 、‘，
LU
