Transient Simulation of Ventilation Rate and Moisture load for Cold Attic Constructions - A CFD Analysis
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Typ
Examensarbete för masterexamen
Master Thesis
Master Thesis
Program
Applied mechanics (MPAME), MSc
Publicerad
2015
Författare
Hellsvik, Ragnar
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
In this Master's thesis, numerical modeling of transient air, heat and mass transport is investigated in a principal cold attic construction through the use of the commercial CFD software ANSYS Fluent. A numerical model that was developed and validated for steady state simulations in an earlier project is now being used for transient simulations over a total time of 24 hours to capture the daily variations in temperature and humidity levels. The attic model contain wooden joists lying in a layer of insulation at the bottom of the attic, and a triangular shaped air cavity. Natural convection due to the temperature gradients between the hot floor and the cold roof along with forced convection driven by the ventilation system is investigated. An hygrothermal analysis and numerical methods are applied to estimate the moisture load at the inner roof boundary for different ventilation rates. The project has been performed as a collaboration between ÅF Industry AB and the Division of Building Technology at Chalmers University of Technology.
Beskrivning
Ämne/nyckelord
Building Futures , Husbyggnad , Building Futures , Building Technologies