TWO- AND THREE-DIMENSIONAL TRANSIENT ANALYSIS OF FLOW AND HEAT TRANSFER IN STRUCTURES WITH DOMICAL AND CURVED ROOFS

Year 2017, , 1489 - 1497, 19.09.2017

Zekeriya Altaç

https://doi.org/10.18186/journal-of-thermal-engineering.338895

Cited By: 1

Abstract

The aim of this study is to investigate transient
buoyancy driven free convection heat transfer in domical (with a dome)
structures or curved roofs is numerically. Two- and three-dimensional turbulent free
convection are considered for the Rayleigh number intervals (10⁸≤Ra≤10¹⁰). The aspect ratios
of H/L=1 and 2, with respect to the
heated length, are considered. The heating is provided from a lateral surface
while cooling is from opposing lateral surface. The hot and cold surfaces are
kept isothermal, and all other surfaces are adiabatic. The Boussineq
approximation is used for modeling the buoyancy flow. The RNG k-e turbulence model is used. The pertinent
transient equations are solved using Fluent 6.3.26 software. The flow of air
(streamlines) and temperature distribution (isotherms) are produced. The mean
Nusselt number is evaluated over the isothermal hot wall is computed, and the
results are analyzed with respect to the flow and geometric variations.  The mean Nusselt number using the 2-D
simulations indicate that the mean Nusselt number does not significantly change
with H/L ratio. The 3-D simulations
yield higher mean Nusselt numbers, but they are smaller than those of obtained
for flat top enclosures.

Keywords

Buoyancy Flow, Domical Structure, Natural Convection, Turbulent Heat Transfer

References

• [1] P. Heiselberg, S. Murakami, and C. Roulet, “Ventilation of large spaces in buildings: Analysis and Prediction Techniques”, IEA, Energy Conservation in Buildings and community Systems, Annex 26: Energy Efficient Ventilation of Large Enclosures. Kolding Trykcenter A/S, Denmark, 1998.
• [2] M. Khalili, S. Amindeldar, “Traditional solutions in low energy buildings of hot-arid regions of Iran”, Sustainable Cities and Society, vol. 13, pp. 171-181, 2014.
• [3] M.N. Bahadori and F. Haghighat, “Passive cooling in hot, arid regions in developing countries by employing domed roofs and reducing the temperature of internal surfaces”, Building and Environment, vol. 20 (2), pp. 103-113, 1985.
• [4] A. Laouadi and M. R. Atif, “Natural convection heat transfer within multi-layer domes”, International Journal of Heat and Mass Transfer, vol. 44(10), pp. 1973-1981, 2001.
• [5] R. Tang, I.A. Meir, and Y. Etzion, “Thermal behavior of buildings with curved roofs as compared with flat roofs”, Solar Energy, vol. 74(4), pp. 273-286, 2003.
• [6] Y. Lin and R. Zmeureanu, “Three-dimensional thermal and airflow (3D-TAF) model of a dome-covered house in Canada”, Renewable Energy, vol. 33(1), pp. 22-34, 2008.
• [7] Y. Lin and R. Zmeureanu, “Computer model of the airflow and thermal phenomena inside a large dome”, Energy and Buildings, vol. 40(7), pp. 1287-1296, 2008.
• [8] A.K. Faghih and M. N. Bahadori, “Thermal performance evaluation of domed roofs”, Energy and Buildings, vol. 43(6), pp. 1254-1263, 2011.
• [9] S. Hussain and P. H. Oosthuizen, “Numerical investigations of buoyancy-driven natural ventilation in a simple atrium building and its effect on the thermal comfort conditions”, Applied Thermal Engineering, vol. 40, pp. 358-372, 2012.
• [10] A. Baïri and J. M. García de María, “Numerical and experimental study of steady state free convection generated by constant heat flux in tilted hemispherical cavities”, International Journal of Heat and Mass Transfer, vol.66, pp. 355-365, 2013.
• [11] A. Baïri, E. Monier-Vinard, N. Laraqi, I. Baïri, M.N. Nguyen, and C.T. Dia, “Natural convection in inclined hemispherical cavities with isothermal disk and dome faced downwards. Experimental and numerical study”, Applied Thermal Engineering, vol. 73(1), pp. 1340-1347, 2014.
• [12] A. Baïri, “A synthesis of correlations on quantification of free convective heat transfer in inclined air-filled hemispherical enclosures”, International Communications in Heat and Mass Transfer, vol. 59, pp. 174-177, 2014.
• [13] A. Baïri and H.F. Öztop, “Free convection in inclined hemispherical cavities with dome faced downwards. Nu–Ra relationships for disk submitted to constant heat flux”, International Journal of Heat and Mass Transfer, vol. 78, pp. 481-487, 2014.
• [14] H. Zhang, F. Niu, Y. Yu, S. Zhang, H. Wang, and Z. Gang, “Modeling and experimental studies on mixing and stratification during natural convection in containments”, Annals of Nuclear Energy, vol. 85, pp. 317-325, 2015.
• [15] H.F. Oztop, F. Selimefendigil, E. Abu-Nada, and K. Al-Salem, “Recent developments of computational methods on natural convection in curvilinear shaped enclosures”, Journal of Thermal Engineering, vol. 2(2), pp. 693-698, 2016.
• [16] Fluent 6.3 Users' Guide, Fluent Inc., Lebanon, NH, 2006.
• [17] I.Catton, “Natural Convection in Enclosures”, Proc. 6th Int. Heat Transfer Conf., Toronto, Canada, pp. 13–31, Vol. 6, Press,1978.
• [18] A. Baïri, “Nusselt–Rayleigh correlations for design of industrial elements: Experimental and numerical investigation of natural convection in tilted square air filled enclosures”, Energy Conversion and Management, vol.49 (4), pp. 771-782, 2008.