The Effect of Asymmetrically Confined Circular Cylinder and Opposing Buoyancy on Fluid Flow and Heat Transfer

Abstract:

In this paper, a two-dimensional numerical investigation is carried out to understand the effects of opposing thermal buoyancy and Prandtl number on fluid flow and mixed convection heat transfer characteristics of symmetrically and asymmetrically confined cylinder submerged in Newtonian fluid. The detailed flow and temperature field are illustrated in term of streamlines and isotherm contours to interpret the flow and thermal transport visualization. The numerical results are presented and discussed for the range of conditions as: Ri = 0 to -4, Pr = 0.7 to 50, eccentricity factor ε = 0 to 0.7 at Re = 40 and for a fixed blockage parameter B = 0.2. The effect of opposing buoyancy is brought about by varying Richardson numbers. The overall drag coefficient and average Nusselt number are computed to elucidate the role of Prandt number, eccentricity factor and Richardson number on the flow and heat transfer. At ε = 0, it is found that, when the buoyancy is opposed the flow becomes asymmetrically and some rotating zones appear under and above the cylinder. Moreover, the eccentricity factor has a tendency to decrease the rotating regions and to increase the heat transfer rate. For example an increase in eccentricity factor from 0 to 0.6 increases Nu by 77% at Ri = 4.

• Periodical: Defect and Diffusion Forum (Volume 374)
• Pages: 18-28
• DOI: https://doi.org/10.4028/www.scientific.net/DDF.374.18
• Online since: April 2017
• Authors: Houssem Laidoudi*, Mohamed Bouzit
• Keywords: Eccentricity Factor, Heat Transfer, Mixed Convection, Opposing Buoyancy, Recirculation Zone, Richardson Number

References

[1] A.K. Dhiman et al., Steady flow across a confined square cylinder: Effects of power-law index and blockage ratio, J. Non-Newtonian Fluid Mech. 148(2008)141-150.

DOI: 10.1016/j.jnnfm.2007.04.010

[2] D. Greenblatt, I. J Wygnanski, The control of flow separation by periodic Excitation, Pro. Aero. Sci. 36(2000)487-545.

DOI: 10.1016/s0376-0421(00)00008-7

[3] C. Sasmal, R.P. Chhabra, Effect of aspect ratio on natural convection in power-law liquids from a heated horizontal elliptic cylinder, Int. J. of Heat and Mass Transfer 55(2012) 4886-4899.

DOI: 10.1016/j.ijheatmasstransfer.2012.04.062

[4] H. Laidoudi, M. Bouzit, Mixed convection in Poiseuille fluid from asymmetrically confined heated circular cylinder, Thermal Science 00(2016)172-172.

DOI: 10.2298/tsci160424172l

[5] Dipankar Chatterjee, Bittagopal Mondal, Effect of thermal buoyancy on vortex shedding behind a square cylinder in cross flow at low Reynolds numbers, I. J. of Heat and Mass Transfer. 54(2011)5262-5274.

DOI: 10.1016/j.ijheatmasstransfer.2011.08.016

[6] H. Laidoudi, M. Bouzit, The local Nusselt number a long square cylinder immersed in power-law fluids under aiding thermal buoyancy, The third I. C. on Fracture Mechanics, Chlef-Algeria. (2016).

DOI: 10.4028/www.scientific.net/df.16.45

[7] Neha Sharma, Amit K. Dhiman, Surendra Kumar, Mixed convection flow and heat transfer across a square cylinder under the influence of aiding buoyancy at low Reynolds numbers. I. J. of Heat and Mass Transfer, 55(2012) 2601-2614.

DOI: 10.1016/j.ijheatmasstransfer.2011.12.034

[8] H. Laidoudi, M. Bouzit, Investigation des fluides Non-newtonien et transfert de chaleur autour d'un cylindre chaud, J. of Advanced Research in Science and Technology, 4(2017)421-432.

[9] Jaber Aboueian, Jahromi, Amin Behzadmehr, Effects of inclination angle on the steady flow and heat transfer of power-law fluids around a heated inclined square cylinder in a plane channel, J. of Non-Newtonian Fluid Mechanics, 166(2011)1406-1414.

DOI: 10.1016/j.jnnfm.2011.09.004