Yıl: 2010 Cilt: 30 Sayı: 1 Sayfa Aralığı: 99 - 110 Metin Dili: Türkçe İndeks Tarihi: 29-07-2022

Natural convection in a triangular cross section roof under daylight conditions

Öz:
Dikey duvarında adyabatik, alt duvarında sabit sıcaklık ve eğik duvarda gün ışığına bağlı olarak yedi farklı sabit ısı akısı sınır şartları altında üçgen kesitli çatıda doğal taşınım sayısal olarak incelenmiştir. Sürekli, laminer ve iki boyutlu durum için süreklilik, momentum ve enerji denklemleri sonlu hacim metodu kullanılarak çözülmüştür. Akım çizgileri, eş sıcaklık eğrileri, yerel ve ortalama Nusselt sayıları AR=0.25, 0.5, 0.75 ve Ra=$10^3, 10^4, 10^5, 10^6 $için sunulmuştur. Isı akısı gün ışığına bağlı olarak 163 W/$m^2$ ile 808 W/$m^2$ arasında değişmiş ve Prandtl sayısı 0.7 olarak alınmıştır. Alt duvar ve eğik duvarda ısı transferinin en-boy oranı ve Rayleigh sayısı tarafından oldukça fazla etkilenirken ısı akısı tarafından hafif şekilde etkilendiği belirlenmiştir.
Anahtar Kelime:

Konular: Termodinamik

Gündüz şartlarında üçgen kesitli çatıda doğal taşınım

Öz:
The natural convection is numerically investigated in a roof of triangular cross section under constant heat flux with seven different values depending on daylight on the inclined wall, constant wall temperature on the bottom wall and adiabatic on the vertical wall boundary conditions. Continuity, momentum and energy equations are solved by using finite volume method for laminar, two-dimensional and steady-state regime. Streamlines, isotherms, local and mean Nusselt numbers are presented for AR=0.25, 0.5, 0.75 and 1.0 and Ra=$10^3, 10^4, 10^5, 10^6$. The amount of heat flux ranges from 163 W/$m^2$ to 808 W/$m^2$ depending on daylight and the Prandtl number is chosen as 0.7. It is found out that the aspect ratio and Rayleigh number highly affect the heat transfer on the bottom and inclined walls while heat flux slightly affects.
Anahtar Kelime:

Konular: Termodinamik
Belge Türü: Makale Makale Türü: Araştırma Makalesi Erişim Türü: Erişime Açık
0
0
0
  • Akinsete, V. and Coleman, T.A., Heat Transfer by Steady Laminar Free Convection in Triangular Enclosures, Int. J. Heat Mass Transfer 25, 991-998, 1982.
  • Asan, H. and Namli, L., Laminar Natural Convection in a Pitched Roof of Triangular Cross-Section: Summer Day Boundary Conditions, Energy and Buildings 33, 69–73, 2000.
  • Asan, H. and Namli, L., Numerical Simulation of Buoyant Flow in a Roof of Triangular Cross Section under Winter Day Boundary Conditions, Energy and Buildings 33, 753–757, 2001.
  • Basak, T., Roy, S. and Thirumalesha, Ch., Finite Element Analysis of Natural Convection in a Triangular Enclosure: Effects of Various Thermal Boundary Conditions, Chemical Engineering Science 62, 2623- 2640, 2007.
  • Basak, T., Roy, S. and Aravind, G., Analysis of Heat Recovery and Thermal Transport within Entrapped Fluid Based on Heatline Approach, Chemical Engineering Science 64(8), 1673-1686, 2009a.
  • Basak, T., Aravind, G. and Roy, S., Visualization of Heat Flow due to Natural Convection within Triangular Cavities Using Bejan's Heatline Concept. Int. J. Heat and Mass Transfer 52(11-12), 2824-2833, 2009b.
  • Gray, D. D. and Giorgini, A., The Validity of the Boussinesq Approximation for Liquids and Gases, Int. J. Heat Mass Transfer 19, 545-551, 1976.
  • Haese, P.M. and Teubner M.D., Heat Exchange in an Attic Space, Int. J. Heat Mass Transfer 45, 4925-4936. 2002.
  • Hajri, I., Omri, A. and Nasrallah S. B., A Numerical Model for the Simulation of Double-Diffusive Natural Convection in a Triangular Cavity Using Equal Order and Control Volume Based on the Finite Element Method, Desalination 206, 579-588, 2007.
  • Holtzman, G. A., Hill, R. W. and Ball, K. S., Laminar Natural Convection in Isosceles Triangular Enclosures Heated from Below and Symmetrically Cooled from Above, J. Heat Transfer 122, 485-491, 2000.
  • Karyakin, Y. E., Sokovishin, Y. A. and Martynenko, O. G., Transient Natural Convection in triangular enclosures, Int. J. Heat Mass Transfer 31, 1759-1766, 1988.
  • Kent, E. F., Asmaz, E. and Ozerbay, S., Laminar Natural Convection in Right Triangular Enclosures, Heat Mass Transfer 44, 187-200, 2007.
  • Kent, E. F., Numerical Analysis of Laminar Natural Convection in Isosceles Triangular Enclosures, Proc. IMechE Part C: J. Mechanical Engineering Science 223(5), 1157-1169, 2009a.
  • Kent, E. F., Numerical Analysis of Laminar Natural Convection in Isosceles Triangular Enclosures for Cold Base and Hot Inclined Walls, Mechanics Research Communications 36(4), 497-508, 2009b.
  • Koca, A., Oztop, H. F. and Varol, Y., The Effects of Prandtl Number on Natural Convection in Triangular Enclosures with Localized Heating from Below, Int. Commun. Heat and Mass Transfer 34, 511-519, 2007.
  • Oztop, H. F., Varol, Y. and Koca, A., Laminar Natural Convection Heat Transfer in a Shed Roof with or without Eave for Summer Season, Applied Thermal Engineering 27, 2252-2265, 2007.
  • Poulikakos, D. and Bejan, A., The Fluid Mechanics of an Attic Space, J. Fluid Mechanics 131, 251-269, 1983.
  • Ridouane, E. H., Campo, A. and McGarry, M., Numerical Computation of Buoyant Airflows Confined to Attic Spaces under Opposing Hot and Cold Wall Conditions, Int. J. Thermal Science 44, 944-952, 2005.
  • Tzeng, S. C., Liou, J. H. and Jou, R. Y., Numerical Simulation-Aided Parametric Analysis of Natural Convection in a Roof of Triangular Enclosures, Heat Transfer Engineering 26, 69–79, 2005.
  • Varol, Y., Koca, A. and Oztop, H. F., Laminar Natural Convection in Saltbox Roofs for both Summerlike and Winterlike Boundary Conditions, Journal of Applied Sciences 6 (12), 2617-2622, 2006a.
  • Varol, Y., Koca, A. and Oztop, H. F., Natural Convection in a Triangle Enclosure with Flush Mounted Heater on the Wall, Int. Commun. Heat Mass and Transfer 33, 951–958, 2006b.
APA KÜÇÜK H, Gedikli H (2010). Natural convection in a triangular cross section roof under daylight conditions. , 99 - 110.
Chicago KÜÇÜK HAYDAR,Gedikli Hasan Natural convection in a triangular cross section roof under daylight conditions. (2010): 99 - 110.
MLA KÜÇÜK HAYDAR,Gedikli Hasan Natural convection in a triangular cross section roof under daylight conditions. , 2010, ss.99 - 110.
AMA KÜÇÜK H,Gedikli H Natural convection in a triangular cross section roof under daylight conditions. . 2010; 99 - 110.
Vancouver KÜÇÜK H,Gedikli H Natural convection in a triangular cross section roof under daylight conditions. . 2010; 99 - 110.
IEEE KÜÇÜK H,Gedikli H "Natural convection in a triangular cross section roof under daylight conditions." , ss.99 - 110, 2010.
ISNAD KÜÇÜK, HAYDAR - Gedikli, Hasan. "Natural convection in a triangular cross section roof under daylight conditions". (2010), 99-110.
APA KÜÇÜK H, Gedikli H (2010). Natural convection in a triangular cross section roof under daylight conditions. Isı Bilimi ve Tekniği Dergisi, 30(1), 99 - 110.
Chicago KÜÇÜK HAYDAR,Gedikli Hasan Natural convection in a triangular cross section roof under daylight conditions. Isı Bilimi ve Tekniği Dergisi 30, no.1 (2010): 99 - 110.
MLA KÜÇÜK HAYDAR,Gedikli Hasan Natural convection in a triangular cross section roof under daylight conditions. Isı Bilimi ve Tekniği Dergisi, vol.30, no.1, 2010, ss.99 - 110.
AMA KÜÇÜK H,Gedikli H Natural convection in a triangular cross section roof under daylight conditions. Isı Bilimi ve Tekniği Dergisi. 2010; 30(1): 99 - 110.
Vancouver KÜÇÜK H,Gedikli H Natural convection in a triangular cross section roof under daylight conditions. Isı Bilimi ve Tekniği Dergisi. 2010; 30(1): 99 - 110.
IEEE KÜÇÜK H,Gedikli H "Natural convection in a triangular cross section roof under daylight conditions." Isı Bilimi ve Tekniği Dergisi, 30, ss.99 - 110, 2010.
ISNAD KÜÇÜK, HAYDAR - Gedikli, Hasan. "Natural convection in a triangular cross section roof under daylight conditions". Isı Bilimi ve Tekniği Dergisi 30/1 (2010), 99-110.