Influence of the cavity geometry on the heat transfer conditions inside highly perforated bricks

0479497 - ÚTAM 2018 RIV US eng C - Conference Paper (international conference)
Kočí, V. - Kočí, J. - Maděra, J. - Beran, Pavel - Černý, R.
Influence of the cavity geometry on the heat transfer conditions inside highly perforated bricks.
Proceedings of the International Conference of Numerical Analysis and Applied Mathematics (ICNAAM 2016). Melville, NY: AIP Publishing, 2017 - (Simos, T.; Tsitouras, C.), č. článku 290007. AIP Conference Proceedings, 1863. ISBN 978-0-7354-1538-6. ISSN 0094-243X.
[International Conference of Numerical Analysis and Applied Mathematics (ICNAAM 2016). Rhodes (GR), 19.09.2016-25.09.2016]
R&D Projects: GA ČR(CZ) GBP105/12/G059; GA MŠMT(CZ) LO1219
Keywords : hollow bricks * cavity geometry * thermodynamic processes * thermodynamic properties
OECD category: Construction engineering, Municipal and structural engineering
http://aip.scitation.org/doi/pdf/10.1063/1.4992444

Heat transfer conditions inside a segment of highly perforated bricks are investigated in the paper. The main objective of the presented analysis is to quantify the influence of the cavity geometry and orientation on the equivalent thermal conductivity of the segment. Five cavities with the same area but different shape are assumed. The calculations are performed by finite element method, while the steady-state two-dimensional heat transfer is assumed. Considering the generalized heat-conduction model, radiative heat fluxes on the cavity surface are quantified based on view factors determined using the cross-string method. Calculated radiative heat fluxes are explicitly added to the surface cavity nodes. Then, after convergence of the temperature field, equivalent thermal conductivity of the segment can be expressed. The results show that circle-shaped cavity exhibits the lowest radiative heat transfer but the lowest equivalent thermal conductivity is obtained when triangle cavities are assumed. The radiative heat transfer is found significant for all analyzed cavities, it can account for more than 30 % of the overall heat transfer.
Permanent Link: http://hdl.handle.net/11104/0275485