Methodology for optical characterization of multi-scale morphologically complex heterogeneous media - Application to snow with soot impurities

摘要

Theradiativecharacterizationofheterogeneousmediawithcomplexmorphologiesonmultiplescalesisofinterestinavarietyofareassuchassolarenergyconversiontechnologiesorenvironmentalsciences.Anin-depthunderstandinganddecouplingofthemulti-scalemorphologicaleffects,bulkmaterialproperties,andoperatingconditionsonthemacroscopicbehaviourprovidespathwaysformorphologytailoringonmultiplescalesforimprovedapplicationperformance.Weintroduceamulti-scalemethodologyforthecharacterizationofthespectralradiativetransportinheterogeneousmediawithcomplexmorphologiesontwodistinctscalescharacterizedbysizeparameters(π-diameter/wavelength)significantlyaboveandbelowone.Themethodologyincorporatestheexactmorphologyatthevariousscalesandutilizesvolume-averagingapproacheswiththecorrespondingeffectivepropertiestocouplethescales.Atthelargescalethevolume-averagedcoupledradiativetransferequationsaresolvedutilizingi)effectiveradiativetransportpropertiesobtainedbydirectMonteCarlosimulationsatthemiddlescale(mmrange),andii)averagedbulkmaterialpropertiesobtainedatthesmallscale(submicronscale)bydiscretedipoleapproximationcalculations.Themethodisexemplaryappliedtosnowcontainingagglomeratedsootimpurities.Aquantificationanddecoupledunderstandingofthemorphologicaleffectontheradiativetransportisachievedandasignificantinfluenceofthedual-scalemorphologyonthemacroscopicopticalbehaviourisobserved...