Page 138 - konishipaper

2826 FIRE-Igni世onandFlameSpread <COMMJENTS
HowardRos，NASAGlenReseaγchCente，rUSA.明That causes出ecoldtemperaturevaley?Theresultsandcon- clusionarealmostcertainlygeometry-dependen.tPulsating spreadisobservedinshalowtrays(relativetowidthand length)withoutacoldtemper此urevaley.Also，models (Schileretal.)pre占ctnoCTVwhile此 也esametime predictingpulsatingspread.Thereforeonemayquestion thegeneralityoftheconclusionthatonenedsaCTVto getpulsatingspread.
Authoγ旨Reply.Forasuficientlydeppol(~ 1cm)the cold tempera加 re val ley is -iesponsible for the flame pul- sation.Forasuficientlyshalowpol(probablyles也at1 mm)，也etimeforaflamablevaportosatisfythelean flamabilitylimitisresponsiblefortl1eflamep叫sation. F o r a l i q u i d p o o l w h o s e d e p t h is b e t w e e n 1 m m a n d 1 c m ， theflamepulsationwilbedeterminedbythecombination ofliquid-andgas-phasephenomena.
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MichaelDelichatsios，CSIRO，Australia.Themainrea- sonforsteadyflamespreadinyourupw訂 dflamespread situationis出atthematerialbumsout(orcharsout).This situationisrepresentedbyyourexperiments.Theefects ofwid也 aretochange也eχf:lχp(flamelength/pyrolysis length)ratioandtheheatfluxtothesurface.Canyouex- trapolatetheresultsforinfinitewidthanddiscusthein- terpretation? Rough砂 spe出 ng，也ebumoutlengthis lb=μstBwhereμsistl1espreadvelocityandtnisbumout time.
Autho作 Reply.Whenaflamestopsatstep(a)，thetwo- dimensional(x-y)flamefrontisnearlystraight.Whena flamespreads此 step(b)，出e.two-dimensionalflamefront becomesparabolicinshape，indicatingafasterspreadrate atthecenterandasloweronenearthesidewal.Because oftheunevensurfacewave-spreadrate，coldliquidcircu- la仕on(~4 to5inmdiameter)isgenerated.Thus，thegrav- ity-drivensurfacewaveisresponsibleforthecoldtem- pera加 revaley[Re.f4inpaper].
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