Transient mass diffusion and convection of volatile organic compounds (VOCs) from walls is an important issue for air quality in buildings. In the present work, a new model of these processes that captures mass transport within the wall structure is presented and applied for a ventilated enclosure. Porous wall structures composed of two solid phases (one carrying the VOC and one inert) and one fluid phase air are generated by the Controllable Structure Generation Scheme (CSGS) based on discrete Gaussian quadrature space and velocity. Mesoscopic scale parallel non-dimensional lattice Boltzmann method (P-NDLBM) simulations are performed for relevant ranges of wall porosity, Reynolds and Schmidt numbers for a two-dimensional enclosure with a top inlet and bottom outlets. The effect of the wall structure on mass transfer in the enclosure is investigated for two wall structures: type (A) a wall with randomly immersed particles, and type (B) a shape-separated wall structure. Results include transient VOC concentration and streamlines in the porous wall and the enclosure for a vary of porosities and diffusivities for each phase. The pore structure and porosity of the wall have significant impact on mass transfer. Type (B) structures are more favorable for rapid mass transfer within the wall.
|Original language||English (US)|
|Number of pages||14|
|Journal||International Journal of Heat and Mass Transfer|
|State||Published - 2018|
Bibliographical noteFunding Information:
Yan Su’s study was supported by Solar Energy Laboratory of University of Macau with projects from the Macao Science and Technology Development Fund No. FDCT/060/2014/A2 , and the Research Committee of the University of Macau No. MYRG2017-00003-FST . The ICTO of University of Macau provided the services of the High Performance Computing Center.
Copyright 2017 Elsevier B.V., All rights reserved.
- Indoor air
- Lattice Boltzmann
- Mass transfer
- Porous medium