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Absor下tioncoeficientshift1α(%)
4. E){perimentalAparatus
Figure8showsthenew1ydeve10pedIR-HIexperimen- ta1aparatusthatcombinesho1ographicinterferome- trywithIRabsorptionthermography.Theho1ographic interferometerwasesentialythesameasthatused inpreviousstudies.9，13，15 The1ightsouycewasa 30mW He-Ne1aser.The1aserbeamwasdividedinto twobeamsbyapartialy1'efiectingmiror.Theobject lightpasedthroughthemixtureofairandfue1va- po1'， whichwasevapo1'atedfromthe1iquidsurfaceof
thefue1tray.ThePyrexfue1traythatwasusedmea sured 20 m m wide X 25 m m de ep X 160 m m 10ng. Theraywasbentovertheliquidsurfaceduetothe densityvariationscausedbyvaporconcentrationand temperatu1'echanges.Theobjectandreferencelight waves interfered with each other at the ho1ogra- phicplate.Real-timeho1ographicinterfe1'omet1'Ywas used.Thefringeshiftscausedbytheevaporationof thefue1wererecordedbyusingaCCDcarnerawitha shuterspedof1/250sandwereinterpretedbyim- ageprocesingsoftware.
ThedetailsoftheIRabso1'ptionaparatusarere- portedinapreviouspaper.14Asolidcopercylinder50 lnfiindiameterand50m mthickwasusedasthe graybodyradiantsou1'ce.Thesurfaceofthe.coper cylinder had a smooth machine fi凶 sh and was paintedwithafiatb1ackpaint.Thetemperatureof thecoperb1acksurfacewassetataproximate1y 120oCastherelativeer1'o1' causedbythegas-phase elnIs sion was within ap proximate1y 30%. The IR therma1radiationemited企omthehotcopersur-
Miror
0.04 0.05 Fig.7. En:orestimatesforIRabsorptionmethodfOI・n-propanol.
0.02 0.03 Spectralemisivityofuelvapor
imate1y30%.Asthepartia1presureofthefue1vapor
decreasedalongwiththezcordinate，there1ative
erordecreased.Theabsorptioncoeficientαfa，"i.(T，p)
isafunctionofwavelength，tempe1'ature，anddensity
of chelnica1 species. Since the temperature depen-
denceoftheabsorptioncoe伍 cientforvaporn-propano1
isunknown，wedonothaveameansofknowingthe
temperature dependence except by guesing 企om
anothergas.Ifthenorma1izedtemperaturechange
Tf/九 is1esthan5，theabsorptioncoeficientchange
is1esthan1%forawatervapor16.4μmband，
carbondioxide15μmband，respective1y.Inourex-
periment，thetelnperaturedependencewasneg1igi-
b1esincethenormalizedtemperatu1'echangewasas
smalasTf/To=313/298=1.05.Thedependenceof facewaspartialyre丑ectedbyaglasmiror.The specieswasuncIearforn-propanolsofaraswein- re丑ectedraypasedthroughthefue1vaporsothat vestigated. theraywassuperimposedontheH←Ne1aser.Since
Holographicplate
Infraredcamera Infraredsource
取引elaser ]_ .
Fig.8. (Co10ronline)Schematicoftheexperimentalaparatususedtomeasurethe2Ddistributionoftemperatureandconcentration
simu1taneous1y.
5730 APPLlEDOPTICS/Vo.l45，No.2/1August206
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