Page 184 - konishipaper

Fig.10. Transmisivityandtemperatureatenuationasa加 lC- tionofpropanolsurfacetemperature.
determine the average absorption mass coef ficient αλm'wedrewastraight1ineinFig.9. Bymeasuring thegradientofthestraight1ine，weobtainedαλm 1.74.
Figure10showsthetransmisivityofifロe1vapor andtemperatureatenuationasafunctionofsurface temperature. Wecalcu1atedthetransmisivityby usingEq.(6)whereα，hf!' andPoarefromourprevi- ousresu1ts.10 Wedeterminedthedecreaseintem- perature by using the Stefan-Bo1tzmann 1aw. Figure11showsthecomparisonbetweenthesurface temperaturemeasuredwithathermocoup1eandthat measuredwiththeIRcamera. Theopencirclesrep聞 resenttheIRtemperaturewithoutcorectionofthe IRabsorptionefectwiththepropano1vapor; the filedcirclesrepresentthecorectedIRtemperature. The45-degdoted1ineindicatesthattheIRtemper- aturepro五1eswiththeIRabsorptioncorectionagree withthethermocoup1edatatowithinanerorof3%.
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4.C.Qian，H.Ishida，andK.Saito“，Upwardflamespreadalong Pl¥日正Averlicalcornerwals，Par七 I，"Combust.Flame9， 31-38(194).
5.M.M.Delichatsios，P.Wu，M.A.，Delichatsios，G.D.Loughed， G.P.Crampton，C.Qian，H.Ishida，andK.Saito“，Efectof
externalradiantheatfl.uxonupwardfirespread: measure mentsonplywod田 ldnumericalpredictions，"inProcedings oftheFourthInternαtionalSymposiumoftheInternational AssociationforFireSafetyScience(SocietyofFireProtection Enginers，Boston，Mas.02109，194).
6.H.RosandF.J.Miler“，Detailedexperlmentsoflamespread acrosdepbutanolpols，"inProcedingsofTwenty-sixth Symposium(Internαtionαl)onCombustion(TheCombustion Institute，Pitsburgh，Pa.15213，196)，p.1327-:134.
7.A.Ito，A.N田 明u，T.Konishi，G.Tashtoush，K.Saito，andC.J. Cremers‘，τ'hemeasurementoftransienttwo-dimensionalpro- 丑lesofvelocityoffuelconcentrationoverliquids，"J.Heat Transfer121，413-419(19).
8.R.SiegelandJ.R.Howel，ThermalRαdiationHeαt7子αnsfer， 3rded.(HemisphereWashington，D.C.，192).
9.P.P.SethnaandD.Wiliams，'fOpticalconstantsofalcoholsin thein企 訂ed，"J.Phys.Chem.83，405-409(1979).
10.T.KOlShi，S.Naka，A.Ito，andK.Saito，附Transienttwo- dimensional fuel-concentr叫 ion measurement technique，" Appl.Opt.36，815-819(197).
20August20/Vo.l39，No.24/APPLlEDOPTICS 4283
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5. ConcJusions
Wedeterminedtheemisivityofliquidpropano1tobe 0.95bymeasuringtheliquidsurfacetemperature withbothanIRcameraanda五nethermocoup1e.The efectofIRabsorptionwithpropano1vaporwasesti- matedasafunctionofliquidtemperaturebetween20 and80oC. IRabsorptionwasfoundtobeneg1igible for a 1iquid with a temperature 1es s than 40oC. Whenthe1iquidtemperaturewasbetween40and 80oC，theIRabsorptionefectincreasedwiththe increase in 1iquid temperature and eventualy reachedthemaximunlvalueofapproximate1y10% absorptionat80oC. OurIRtechniquecanbeused todetectaminimumof0.1oCtemperaturechange withinaminimumresponsetimeof30ms. Theac同 curacyofourIRtechniquehasbeenestimatedtobe beterthan97%versusthetemperaturemeasure同 mentdataobtainedwithathermocoup1e.
Thisstudyisjoint1ysponsoredbytheKentucky- NASAExperimenta1ProgramtoStimulateCompet- itive Research and the Japanese Ministry of Education for Grant-in-Aids for Internationa1 Re- search.
References
1.A.Ito，K.Saito，andT.Inamura，“Temper叫 ures七ructureof liquidphaseinpol五ressuportedonwater: implicationto boiloverphenomenon，"J.HeatTransfer14，94-949(192).
2.A.Arakawa，K.Saito，andW.A.Gruver，An automatedin-
'~
合ared泊四百ngtemperaturemeasurement: withaplication toupwardflamesspreadstudies，"Combust.Flame92，22- 230(193).
3.C.Qi阻，A.Arakawa，H.Ishida，K.Saito，andC.J.Cremers， “Temperaturemeasurementbyir企 aredimageswithaplica-
ch，"inThermalConductivity2，T.W.Tong，
20 40 Surfacetemp町 atureTs(OC)
0.95 80
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o
30 40 50 60 70
ThermocoupletemperatureT (OC) ct
Fig.1. ComparisonofthetemperaturemeasuredwiththeIR cameraandthatmeasuredwiththethermocouple: opencircles， uncorectedIRtemperature;五ledcircles，corectedIRtempera- ture.
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町 ed.(Technomic，Lancaster，Pa.194)，p.973-984.
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