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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Convective to Diffusive Contribution of Mass Transfer in Porous Building Materials through Peclet Number Evaluation

Get access (open in a dialog) DOI: 10.1615/IHTC15.pmd.009774
pages 6731-6744

Abstract

The interest of this paper lays to exanimate the contribution of two main mechanisms: moisture convection and diffusion on HAM (Heat Air and Moisture) transfer in porous building envelopes and to define the validity of the sub-models. Heat transfer is considered in the strongly coupled situation where the mass and heat flux are temperature, total pressure and moisture content dependents. Based on this model, a numerical simulation is performed and focuses on one-dimensional problem for drying test boundary conditions. Temperature and moisture content profiles have been predicted as function of time versus the corresponding physics. Moreover, a detailed parametric analysis was carried out in order to investigate the influence of typical governing parameters over the range of 0.1 Pe  50 , 0.001 Lu 13 , 0.005  Bu 100 , 0.05  Pn  2 , 2  Ko  30 and 0.01 Lup 100 . Results show that convection becomes a prominent driving potential face to the diffusion process when the hygric state is quite stable between the ambiance and the envelope. Thought, at high Pe number convection favors drying comparing to the pure diffusion process.