Simulation of Natural Convection in Concentric Annuli between an Outer Inclined Square Enclosure and an Inner Horizontal Cylinder

In this work, the natural convection in a concentric annulus between a cold outer inclined square enclosure and heated inner circular cylinder is simulated for two-dimensional steady state. The Boussinesq approximation was applied to model the buoyancy-driven effect and the governing equations were solved using the time marching approach staggered by body fitted coordinates. The coordinate transformation from the physical domain to the computational domain is set up by an analytical expression. Numerical results for Rayleigh numbers 103 , 104 , 105 and 106, aspect ratios 1.5 , 3.0 and 4.5 for seven different inclination angles for the outer square enclosure 0o , -30o , -45o , -60o , -90o , -135o , -180o are presented as well. The computed flow and temperature fields were demonstrated in the form of streamlines, isotherms and Nusselt numbers variation. It is found that both the aspect ratio and the Rayleigh number are critical to the patterns of flow and thermal fields. At all Rayleigh numbers angle of inclination has nominal effect on heat transfer.




References:
[1] Shu, C., and Zhu, Y.D., Efficient computational of natural convection
in a concentric annulus between an outer square cylinder and inner
circular cylinder, Int. J. Numer. Meth. Fluid 38 (2002) 429-445.
[2] Kim, B.S., Lee, D.S., Ha, M.Y., and Yoon, H.S., A numerical study
of natural convection in a square enclosure with a circular cylinder at
different vertical locations, Int. J. heat and mass transfer 51 (2008)
1888-1906.
[3] Hyun Sik Yoon, Man Yeong Ha, ByungSoo Kim and Dong Hun Yu,
Effect of the position of a circular cylinder in a square enclosure on
natural convection at Rayleigh number of 107, American Institute of
Physics, PHYSICS OF FLUIDS 21 (047101) (2009).
[4] Hakan F. Oztop, Zepu Zhao and BoYu, Fluid flow due to combined
convection in lid-driven enclosure having a circular body,
International Journal of Heat and Fluid Flow 30 (2009) 886-901.
[5] J.M. Lee, M.Y. Ha and H.S. Yoon, Natural convection in a square
enclosure with a circular cylinder at different horizontal and diagonal
locations, International Journal of Heat and Mass Transfer 53 (2010)
5905-5919.
[6] Salam Hadi Hussain and Ahmed Kadhim Hussein, Numerical
investigation of natural convection phenomena in a uniformly heated
circular cylinder immersed in square enclosure filled with air at
different vertical locations, International Communications in Heat and
Mass Transfer 37 (2010) 1115 -1126.
[7] TalalKassem, Numerical study of the natural convection process in the
parabolic-cylindrical solar collector, The Ninth Arab International
Conference on Solar Energy (AICSE-9), Kingdom of Bahrain,
Desalination 209 (2007) 144-150.
[8] C. Shu ,Q.Yao , K. S. Yao and Y. D. Zhu , Numerical analysis of flow
and thermal fields ia arbitrary eccentric annulus by differential
quadrature method, Heat and Mass Transfer 38 (2002) 597-608.
[9] Arnab Kumar De and AmareshDalal , A numerical study of natural
convection around a square horizontal heated cylinder placed in an
enclosure, International Journal of heat mass transfer 49 (2006) 4608-
4623.
[10]WenRuey Chen, Natural convection heat transfer between inner sphere
and outer vertically eccentric cylinder, International Journal of Heat
and Mass Transfer 53 (2010) 5147-5155.
[11] XuXu, Gonggang Sun, Zitao Yu, Yacai Hu, Liwu Fan, Kefa Cen,
Numerical investigation of laminar natural convective heat transfer
from a horizontal triangular cylinder to its concentric cylindrical
enclosure, International Journal of Heat and Mass Transfer 52 (2009)
3176-3186.
[12] Zi-Tao Yu, Li-Wu Fan, Ya-Cai Hu and Ke-Fa Cen, Prandtl number
dependence of laminar natural convection heat transfer in a horizontal
cylindrical enclosure with an inner coaxial triangular cylinder,
International Journal of Heat and Mass Transfer 53 (2010) 1333-
1340.
[13] Manab Kumar Das and K . Saran Kumar Reddy, Conjugate natural
convection heat transfer in an inclined square cavity containing a
conducting block, International Journal of Heat and Mass Transfer 49
(2006) 4987-5000.
[14] YasinVarol, Hakan F. Oztop, AhmetKoca and FilizOzgen, Natural
convection and fluid flow in inclined enclosure with a corner heater,
Applied Thermal Engineering 29 (2009) 340-350.
[15] H.F. Nouanegue, A. Muftuoglu, E. Bilgen, Heat transfer by natural
convection, conduction and radiation in an inclined square enclosure
bounded with a solid wall, International Journal of Thermal Sciences
48 (2009) 871-880.
[16] F.A. Munir, N.A.C. Sidik and N.I.N. Ibrahim, Numerical Simulation
of Natural Convection in an Inclined Square Cavity, Journal of
Applied Sciences 11 (2) (2011) 373-378.