C027 -- Hygrothermal Simulation—Modelling Airflow along Gap-like 3D Paths in Building Components with Darcy’s Law

Unintendedair owshavebeenrecognisedasadecisivefactorwhenfocusingonmoisturedamages and durabilityinbuildingcomponents(Hens2017).Althougheortshavebeenundertakentobetter quantifyconvectivemoisturetransport(Nusser,Bednar,andTeibinger2010;Kunzel,Zirkelbach,and Schafaczek2010),IEAAnnex41closedwithacriticaloutlookonthe"deeperexploration"ofe.g. integratingair owmodels(EBC2013).Referringtothisnote,thispaperpresentsaninitialapproach howtosimulateair owsinconstructionsalong3Dpaths-tothedierenceof owsinporousmedia - suchasingapsanditsimplementationinhygrothermalsimulation. An introductoryoverviewoftheestablishedwaystomodelair owsinhygrothermalsimulationtools and currentdevelopmentsinthis eldaregiven.Takingintoaccount3Dair owsinthejointsof the insulationasinviscidincompressibleair owsprovedtobeapossibilitytomatchmeasurement data withtheresultsofacoupledheat,airandmoisture(HAM)simulation.Inthisapproach, space availabletoair owwasmodelledaspermeablecells.Aleakageinducingatimedependant pressure dierencewasmodelledasamass owsources.Thedatausedforcomparisonconsistsofan experimentwheretheeectofleakageswhenexposedtopressuredierenceshasbeeninvestigated. The comparisonoftheresultsshowthatwiththisapproachthebehaviouroftheconstructionto the pressuredierencescouldbequalitativelyrecreated.There nementofthephysicalmodeland the experimentalinvestigationofthehygrothermalpropertiesofthegapsandjointsareidenti edas future researchtopics.