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195]，wewilIprovideonlytheequationsforthetemperatureandthe fuelconcentration，respectively.
Where，n=re合activeindex，T=tempera加 re，.Cj=mole企actionof speciesi，P=presure，N =molarrefractivityof'speciesi，R = universa1gasconstantisubscripts:^l=wavelengthoflaserbeam"1 (48nmAr-ionlaser-b巴am)，and~ =wavel~nm~ oflaserbeam2 (632nmHe-Nelaser-beam)，a=air，f=白e.l
fi1ters were used to separate the two holograni's. 百 lese filters have narowband-paswidths，eachpasingthewavelengthmatchtothat ofitsrespectivelaser-beam.
RESULTSANDDISCUSSION PTLSResults
Figure 3 shows a schematic of the pulsating flame spread
consistingofsixdiferentsteps. Figure4showsthegasphaseSTT
andliquidph出 eP1LS(representative)photographsforfourdiferent
steps(a，b，c，andd1). Figur~ 5shows2-Dflowvectordiagramsfor
steps(a，b.c.andd1). .Step(a)isthebeginingofthecycle.of
pulsationandtheproc回 smovesontosteps(b).(c)，(d1)，(dρ，(e)，
andreturnstoばep(a)tocompletethecycle. 百leschematicofstep
(d )， not shown in the origina1 diagram published in 19 91 [lto， 1
Masada，andSaito，191]，wasadedbecauseithelpsusunderstand theprocesofflamepulsationbeter.
Atstep(a)theflamβspreadsslowlytoぬeleftandtheremaybe abuoyancy-inducedairflowoverthefuelsurfaceaheadof出eflame. 官 lere is a hot zone fon ned in liquid phase near the flame's leading edge.butnosurfacetensionflowwasformedintheliquidphase. At step (b) the flame spreads faster than the s均 (a) generating a su巾 印 却nsionflowwhichflowsinthe.samedirectionastheflame.
inducedairflowwhichmoves Inthegasphase.thereisabuoyancy
同
againsttheflamespreaddirection. Thebuoyancy-inducedairflow 飢 dtheliquidsurface-tensionflowdirectagainsteachothercreating asmalcirculationinthegasphasejustaheadoftheflameleading edge c印 ating a flamable gas-air rnixture over the extended upstreamdirection.官lUS，theaircirculationre副ona1so.increasedits diameterintheupstre包 ndirectionpreparingforafastぺjump"flame spread(stepd1)t9ocur. Becauseofasudenincreas~ oftheflame spreadrateatstep(dJ)，athermalexpansionoftheair駄 目 placein thecirculationzonedestroyingthecirculationanclcreatinganewair fJow.concur rent to the flame spread. This concur rent air flow
T - ( 3 P / 2 R ) N A h ( N B - N A ) λ 2 - N U 2 { N B - N A )λ1
一
(ト 1)入1(NB-NA)九2一(ト 1)λ2(NB-NA)kl c = (~-lh2Nkγ1 一(ト 1)λlNA'A.2
ー一
(n-:-1)λ1(NB- NA)λ2一(n-l)λ2(NB- NA)λ1 百lesymbolsNintheaboveequationsaredefinedas:
:d
(a)
(c) .
恥町
M
ionflow
ノセ号
刷...
nna計l
NA=N +~(N:a'A.
Aλ
Buoyancyinqucedtlow→ぞ丸山、 Gas "Q，'-'::
~:J1Jl
川、~
山口下'-.:.;忠雄:Jf
...
f;:.~，:~.，
!?2論議採
Recirc
STF/
A
主主
-NAλ)
(2)
(3)
内認惑に
Flame
...h~
ferel)twavelengths 加h1010gra却phi匂cplate. 官len，duringtheprintingtroces，twodiferent
DW加h1010gra叩Iπmscontain加h1叫0ologra叩Im町 softwo
i
t削ha討t阿n削E吋凶山tωo加b“ese馴p阿附阿紅ω削a蹴制t
辺
司訓
【
4ょでち増さ吾妻~= aceleratestheliquidsurface-tensionflow.flamespreadsalongwith the flow. and eventual ly the flame almost stops after the flame leading~ge reachestheheadoftheliquidflow(stepd2). A few S民 ondslater，step(e)takesplace.Thentheprocesretumedtostep
ミ;:/
(a)completingthewholeproces(1同 Masuda.andSai肌 191， providesfiveinterferogramscorespondingto・stepsa，b，cd2ande).
STIResults Fourdiferentsmokestreakphotographsforsteps(a，b，c，and
d1)areshowninFigs.4(a)，(b)， (c)and(d1).Figure4(a)，where出e
spreadrateis 1.2cmls，showsnoliquideonvectiveand surface-tensionflowsandtheresemstobeasmalfJame-inducedair t}owwhichwasclearbyvisua1observation.butnotc
(d)
2 4
(吋ω)e 、、i:ミi~》ミ~;d:t濯:/ぜ::三乏;三t 、、、叡~吋~ミ二三~戸~
ア4喝さぎH F
Flgure3 Schem~tlc~ 01thepulsatlngflamespread.，
144
flam~
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