## THERMAL SCIENCE

International Scientific Journal

### STUDY OF CONVECTION HEAT TRANSFER ENHANCEMENT INSIDE LID DRIVEN CAVITY UTILIZING FINS AND NANOFLUID

**ABSTRACT**

In the present study, the effect of suspension of nanoparticle on mixed convection flow is investigated numerically in lid driven cavity with fins on its hot surface. Study is carried out for Richardson numbers ranging from 0.1 to 10, fin(s) height ratio change from 0.05 to 0.15 and volume fraction of nanoparticles from 0 to 0.03, respectively. The thermal conductivity ratio (kfin/kf) is equal to 330 and Grashof number is assumed to be constant (104) so that the Richardson numbers changes with Reynolds number. Results show that the heat transfer enhances by using nanofluid for all studied Richardson numbers. Adding fins on hot wall has different effects on heat transfer depend to Richardson number and height of fins. Use of low height fin in flow with high Richardson number enhances the heat transfer rate while by increasing the height of fin the heat transfer reduces even lower than it for pure fluid. The overall enhancement in Nusselt number by adding 3% nanoparticles and 3 fins is 54% at Ri=10. They cause reduction of Nusselt Number by 25% at Ri=0.1. Higher fins decrease the heat transfer due to blocking fluid at corners of fins.

**KEYWORDS**

PAPER SUBMITTED: 2015-01-25

PAPER REVISED: 2015-10-07

PAPER ACCEPTED: 2015-10-23

PUBLISHED ONLINE: 2015-11-15

**THERMAL SCIENCE** YEAR

**2017**, VOLUME

**21**, ISSUE

**6**, PAGES [2431 - 2442]

- Imberger, J. and Hamblin, P. F., Dynamics of lakes, reservoirs, and cooling ponds, Annual Review of Fluid Mechanics, 14(1982), pp. 153-187.
- Vahl Davis, G. D., Natural Convection of Air in Square Cavity: A Bench Mark Solution, Int. J. for Numerical Methods in Fluids, 3(1983), pp. 249-264.
- Schreiber R., Keller, H. B.,Driven cavity flows by efficient numerical techniques, Journal of Computational Physics,49(1983) 310-333.
- Iwatsu, R., et al., Mixed convection in a driven cavity with a stable vertical temperature gradient, Int. J. Heat Mass Transfer, 36(1993), pp. 1601-1608.
- Moallemi, M. K., Jang, K. S.,Prandtl number effects on laminar mixed convection heat transfer in a lid-driven cavity, Int. J. Heat Mass Transfer, 35(1992), pp. 1881-1892.
- A. K. Prasad and J. R. Koseff, Combined forced and natural convection heat transfer in a deep liddriven cavity flow, Int. J. Heat Fluid Flow,17(1996) 460-467.
- Leong, J. C., et al, Mixed convection from an open cavity in a horizontal channel, Int. Commun. Heat Mass Transfer, 32(2005), pp. 583-592.
- Darzi, A.A.R, et al, Numerical study of the fins effect on mixed convection heat transfer in a liddriven cavity, Proc. Inst. Mech. Eng. C J. Mech. Eng. Sci., 225(2011), pp. 397-406.
- Ko, T.H., Ting, K., Optimal Reynolds number for the fully developed laminar forced convection in a helical coiled tube, Energy, 31 (2006) 2142-2152.
- Hajmohammadi, M.R., et al., Essential reformulations for optimization of highly conductive inserts embedded into a rectangular chip exposed to a uniform heat flux, Proc. Inst. Mech. Eng. C J. Mech. Eng. Sci., 228 (2014) , pp. 2337-2346.
- Hajmohammadi, M.R., et al., Evolution in the Design of V-Shaped Highly Conductive Pathways Embedded in a Heat-Generating Piece, J. Heat Transfer 137 (6), pp. 061001-7.
- Hajmohammadi, M.R., et al., Controlling the heat flux distribution by changing the thickness of heated wall, J. Basic. Appl. Sci. Res., 2(7)7270-7275, 2 (7), pp. 7270-7275.
- Pouzesh, A., et al., Investigations on the internal shape of constructal cavities intruding a heat generating body, Thermal Science, 19 (2015, pp. 609-618.
- Velagapudi, V., et al., Empirical Correlation to Predict Thermophysical and Heat Transfer Characteristics of Nanofluids, Thermal Science, 12 (2008), 1, pp. 27-37.
- Murugesan, C., Sivan, S., Limits for Thermal Conductivity of Nanofluids, Thermal Science, 14 (1) (2010), pp. 65-71.
- Sourtiji, E., Hosseinizadeh, S. F., Heat Transfer Augmentation of Magneto hydrodynamic Natural Convection in L-Shaped Cavities Utilizing Nanofluids, Thermal Science, 16 (2012), 2, pp. 489-501.
- Öztop, H. F., et al., A brief review of natural convection in enclosures under localized heating with and without nanofluids, Int. Commun. Heat Mass Transfer, 60(2015), pp. 37-44.
- Hajmohammadi, M.R., et al., Effects of Cu and Ag nano-particles on flow and heat transferfrom permeable surfaces, Advanced Powder Technology, 26 (2015) 193-199.
- Mahmoodi, M., et al., Free convection of nanofluid in a square cavity with heat source on the bottom wall and partially cooled from sides, Thermal Science,18(2014), pp.283-300.
- Masuda, H., et al., Alteration of thermal conductivity and viscosity of liquid by dispersing ultra-fine particles, Netsu Bussei,7 (1993) (4), pp. 227-233.
- Choi, U. S., Enhancing Thermal Conductivity of Fluids with Nanoparticles, ASME FED, 231 (1995), pp.99-105.
- Garoosi, F., et al., Numerical simulation of natural convection of nanofluids in a square cavity with several pairs of heaters and coolers (HACs) inside, Int. J. Heat Mass Transfer, 67(2013) 362-374.
- Parvin, S., et al., An analysis on free convection flow, heat transfer and entropy generation in an odd-shaped cavity filled with nanofluid, Int. Commun. Heat Mass Transfer, 50(2014), pp. 8-17.
- A. Abouei Mehrizi, et al., Mixed convection heat transfer in a ventilated cavity with hot obstacle: Effect of nanofluid and outlet port location, Int. Commun. Heat Mass Transfer, 39 (2012) (7), pp.1000-1008.
- Hosseinizadeh, S.F., et al., Numerical investigations of unconstrained melting of nano-enhanced phase change material (NEPCM) inside a spherical container, Int. J. Thermal science, 51(2012), pp. 77-83.
- Ho, C.J., et al., Buoyancy-driven flow of nanofluids in a cavity considering the Ludwig-Soret effect and sedimentation: Numerical study and experimental validation, Int. J. Heat mass transfer, 77 (2014), pp. 684-694.
- Khanafer, K., et al., Buoyancy-driven heat transfer enhancement in a two-dimensional enclosure utilizing nanofluids, Int. J. Heat Mass Transfer, 46 (2003) (19), pp. 3639-3653.
- Talebi, F., et al., Numerical study of mixed convection flows in a square lid-driven cavity utilizing nanofluid, Int. Commun. Heat Mass Transfer, 37 (2010), pp. 79-90.
- Hajmohammadi, M.R., et al., Effects of Cu and Ag nano-particles on flow and heat transfer from permeable surfaces, Advanced Powder Technology, 26 (2015) 193-199.
- Nemati, H., et al., Lattice Boltzmann simulation of nanofluid in lid-driven cavity, Int. Commun. Heat Mass Transfer, 37(2010), pp. 1528-1537.
- Hosseini, M., et al., Nanofluid in tilted cavity with partially heated wall, J. Molecular Liquids. 199 (2014), pp. 545-551.
- Rashidi, I., et al., Natural convection of Al2O3/water nanofluid in a square cavity: Effects of heterogeneous heating, Int. J. Heat Mass Transfer, 74(2014), pp. 391-402.
- Abu-Nada E., Chamkha, A.J., Mixed convection flow of nanofluid in a lid driven cavity with wavy wall, Int. Commun. Heat Mass Transfer, 57 (2014), pp. 36-47.
- Brinkman, H.C., The viscosity of concentrated suspensions and solutions, J. Chemical Physics, 20 (1952), pp. 571-581.
- Patel, H. E., et al., A micro convection model for thermal conductivity of nanofluid, Pramana-Journal of Physics, 65 (2005), pp. 863-869.
- Nourollahi, M.,Generation of CFD code for solving the fluid governing equations in non-orthogonal coordinate systems, MSc. thesis, Babol University of Technology, Iran, 2007.
- Ferziger, J. H., Peric, M., Computational Methods for Fluid Dynamics, Springer-Verlag, Berlin Heidelberg, New York, 2002.
- Farhadi, M., et al., Effect of wall proximity on forced convection in a plane channel with a built-in triangular cylinder, Int. J. Thermal Sciences, 49 (2010), pp. 1010-1018.