An improved model of heat transfer through penguin feathers and down

《An improved model of heat transfer through penguin feathers and down》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

1、ARTICLEINPRESSJournalofTheoreticalBiology248(2007)727–735www.elsevier.com/locate/yjtbiAnimprovedmodelofheattransferthroughpenguinfeathersanddowna,ca,aabNingDu,JintuFan,HuijunWu,ShuoChen,YangLiuaInstituteofTextilesandClothing,TheHongKongPolytechnicUniversity,HungHom,Kowloon,HongKongbDep

2、artmentofMechanicalEngineering,TheHongKongPolytechnicUniversity,HungHom,Kowloon,HongKongcSchoolofMathematicsandSystemScience,ShandongUniversity,Jinan250100,ChinaReceived16April2007;receivedinrevisedform22June2007;accepted25June2007Availableonline4July2007AbstractPenguins,mostlyliveinthe

3、extremelycoldAntarctic,areknowntohavefeathersanddown,whicharelightweight,compactandextremelyefficientinpreventingheatloss.Nevertheless,themechanismsofheattransferthroughthepenguinfeathersanddown,andhowtheuniquecharacteristicsofpenguinfeathersanddownmakethemsuchgoodthermalinsulatorsarenot

4、fullyunderstood.Inthispaper,anintegratedmodelofheattransferthroughthepenguinfeathersanddownisdevelopedandcomputedusingfinitevolumemethod,withthegeometricalstructureofthebarbulesbeingconsidered.Monte-Carlomethodisadoptedtodeterminetheradiativeabsorptionandemissionconstantintheintegratedmo

5、del.Theeffectivethermalconductanceofpenguinfeathersanddowncomputedfromourmodelcomparedwellwiththeexperimentallymeasuredvaluereportedintheliterature.Threemodels(penguinmodel,randomfibremodel(fibreradius¼3mm)andrandomfibremodel(fibreradius¼10mm))arefurthersimulatedandcompared.Resultsshowedtha

6、ttherelativesmallradiusofthebarbulesofpenguinfeatherandtheirgeometricalstructureareresponsibleforthereductionofheatlossincoldenvironment.r2007ElsevierLtd.Allrightsreserved.Keywords:Heattransfer;Penguinfeather;Finitevolume;Monte-Carlo1.IntroductionDawsonetal.(1999)studiedheattransferthro

7、ughGentoopenguinfeathers.Theybelievedthattheinteract-PenguinsmostlyliveintheextremelycoldAntarctic.Itisingbarbulescreatedamultilayerstructure,whichshieldedfascinatingtonotethatpenguins,homeothermsbynature,heattransferduetoradiation.Theyfurtherbelievedthatcanwithstandtheextremel