## THERMAL SCIENCE

International Scientific Journal

### Thermal Science - Online First

online first only
### Numerical study of the turbulent natural convection of nanofluids in a partially heated cubic cavity

**ABSTRACT**

In this work we study numerically the three-dimensional turbulent natural convection in a partially heated cubic cavity filled with water containing metallic nanoparticles, metallic oxides and others based on carbon.The objective is to study and compare the effect of the addition of nanoparticles studied in water and also the effect of the position of the heated partition on the heat exchange by turbulent natural convection in this type of geometry, which can significantly improve the design of heat exchange systems for better space optimization. For this we have treated numerically for different volume fractions the turbulent natural convection in the two cases where the cavity is heated respectively by a vertical and horizontal strip in the middle of one of the vertical walls. To take into account the effects of turbulence, we used the standard turbulence model κ - ε. The governing equations are discretized by the finite volume method using the power law scheme which offers a good stability characteristic in this type of flow. The results are presented in the form of isothermal lines and current lines. The variation of the mean Nusselt number is calculated for the two positions of the heated partition as a function of the volume fraction of the nanoparticles studied in water for different Rayleigh numbers.The results show that carbon-based nanoparticles intensify heat exchange by convection better and that the position of the heated partition significantly influences heat exchange by natural convection. In fact, an improvement in the average Nusselt number of more than 20% is observed for the case where the heated partition is horizontal.

**KEYWORDS**

PAPER SUBMITTED: 2020-05-13

PAPER REVISED: 2020-09-03

PAPER ACCEPTED: 2020-10-30

PUBLISHED ONLINE: 2021-02-06

- Choi, S. U. S., Eastman, J. A., Enhancing thermal conductivity of fluids with nanoparticules, developments and applications of Non -Newtonian flows, American Society of Mechanical Engineers, 231 (1995), pp. 99-105
- Namburu, P. K., et al., Numerical study of turbulent flow and heat transfer characteristics of nanofluids considering variable properties, International Journal of Thermal Science, 48 (2009), pp. 290-302
- Rabhi, R., et al., Influence of magnetohydrodynamic viscous flow on entropy generation within porous micro duct using the Lattice Boltzmann Method, RSC Advance, 7 ( 2017), 49, pp. 30673-30686
- Mirmasoumi, S., Bezadmehr, A., Effect of nanoparticles mean diameter on mixed Convection heat transfer of a nanofluid in a horizontal tube, International Journal of Heat and Fluid Flow, 29 (2008), pp. 557-566
- Irfan, et al., Heat transfer in natural convection flow of nanofluid along a vertical wavy plate with variable heat flux. Thermal Science, 23 (2019), pp. 179-190
- Fallah, et al., Simulation of natural convection heat transfer using nanofluid in a concentric annulus, Thermal Science, 21 (2017), pp. 1275-1286
- Javed, S., et al., Internal convective heat transfer ofnanofluids in different flow regimes, A comprehensive review, PHYSICA A: Statistical Mechanics and its Applications, 538 (2019), doi:10.1016/j.physa.2019.122783
- Mendu, S., et al., Simulation of natural convection of nanofluidsin a square enclosure embedded with bottom discrete heater, Thermal Science, 22 (2018), pp. 2771-2781
- Aghajani Delavar M., et al., Effect of discrete heater at the vertical wall of the cavity over the heat transfer and entropy generation using lattice bolzmann method, Thermal Science, 15 (2011), 2, pp. 423-435
- Terekhov, V. I., et al., Three-Dimensional Laminar Convection in a Parallelepiped with Heating of Two Side Walls, Teplofizika Vysokikh Temperatur, 49 (2011), 6, pp. 905-911
- Mejia-Ariza, R., et al., Formation of hybrid gold nanoparticle network aggregates by specific host-guest interactions in a turbulent flow reactor, Journal of Materials Chemistry B, 2 (2014), pp. 210-216
- Liu, Y., et al., Turbulence in a microscale planar confined impinging-jets reactor, Journal of Materials Chemistry B, 9 (2009), pp. 1110-1118
- Sadiq, M. A., et al., Numerical simulation of oscillatory oblique stagnation point flow of a magneto micropolar nanofluid, RSC Advance, 9 (2019), pp. 4751-4764
- Peng, Y., et al., A numerical simulation for magnetohydrodynamic nanofluid flow and heat transfer in rotating horizontal annulus with thermal radiation, RSC Advance, 9 (2019), pp. 22185-22197
- Sadeghi, G., et al., Experimental and numerical investigations on performance of evacuated tube solar collectors with parabolic concentrator, applying synthesized Cu2O/distilled water nanofluid, Energy for Sustainable Development, 48 (2019), pp 88-106
- Dogonchi, A. S., et al., Heat transfer by natural convection of Fe3O4-water nanofluid in an annulus between a wavy circular cylinder and a rhombus. International Journal of Heat and Mass Transfer, 130 (2019), pp 320-332
- Zaraki, A., et al., Theoretical analysis of natural convection boundary layer heat and mass transfer of nanofluids: Effects of size, shape and type of nanoparticles, type of base fluid and working temperature, Advanced Powder Technology, 26 (2015), 3, pp. 935-946
- Jahanshahi, M., et al., Numerical simulation of free convection based on experimental measured conductivity in a square cavity using Water/SiO2 nanofluid , International Communications in Heat and Mass Transfer, 37 (2010), 6, pp 687-694
- Zangooee, M. R., et al., Hydrothermal analysis of MHD nanofluid (TiO2-GO) flow between two radiative stretchable rotating disks using AGM. Case Studies in Thermal Engineering, 14 (2019), doi: 10.1016/j.csite.2019.100460
- Haddad, O., et al., Free convection in ZnO-Water nanofluid-filled and tilted hemispherical enclosures containing a cubic electronic device, International Communications in Heat and Mass Transfer, 87 (2017), pp 204-211
- Iqbal, S. M., et al., A comparative investigation of AL2O3/H2O, SIO2/H2O and ZRO2/H2O nanofluid for heat transfer applications, Digest Journal of Nanomaterials and Biostructures, 12 (2017), 2, pp 255 - 263
- Aman, S., et al., Impacts of gold nanoparticles on MHD mixed convectionPoiseuille flow of nanofluid passing through a porous mediumin the presence of thermal radiation, Thermal Diffusion and Chemical Reaction. Neural Comput. & Applic., 30 (2018), 3, pp789-797
- Kefayati, G. H. R., Simulation of Ferrofluid Heat Dissipation Effect on Natural Convection at an Inclined Cavity Filled with Kerosene/Cobalt Utilizing the Lattice Boltzmann Method, Numerical Heat Transfer, Part A: Applications, 65 (2014), 6, pp 509-530
- Shafie, Sh., et al., Molybdenum Disulfide Nanoparticles Suspended in Water- Based Nanofluids with Mixed Convection and Flow inside a Channel filled with Saturated Porous Medium, AIP Conference Proceedings, 2nd International Conference on Mathematics, Engineering and Industrial Applications , Songkhla, Thailand, 2016, vol. 1775, Article number 030042
- Sandeep, N., et al., Effects of radiation on an unsteady natural convective flow of a EG-Nimonic 80a nanofluid past an infinite vertical plate, Advances in Physics Theories and Applications, 23 (2013), pp. 36-43
- Benabderrahmane, A., Numerical Study of the Application of Nanofluids in Improving Heat Transfer in Solar Sensors, Ph. D. thesis, Djillali Liabes University, Sidi Bel Abbès, Algérie, 2017 (in French)
- Salman, S. D., et al., Numerical Investigation of Heat Transfer and Friction Factor Characteristics in a Circular Tube Fitted with V-Cut Twisted Tape Inserts, The Scientific World Journal, 1 (2013), pp. 1-8
- Gunnasegaran, P., et al., Numerical Study of Fluid Dynamic and Heat Transfer in a Compact Heat Exchanger Using Nanofluids, International Scholarly Research Network ISRN Mechanical Engineering, 1 (2012), pp. 1-11
- Selimefendigil, F., et al., Mixed convection in a lid-driven cavity filled with single and multiple walled carbon nanotubes nanofluid having an inner elliptic obstacle, Propulsion and Power Research , 8 (2018), 2, pp. 128-137
- Brinkman, H. C., The Viscosity of Concentrated Suspensions and Solutions, Journal of Chemical Physics, 20 (1952), pp 571-581
- Maxwell, J. C., A Treatise on Electricity and Magnetism, Clarendon Press, U.K, 1891
- Pak, B. C., et al., Hydrodynamic and heat transfer study of dispersed fluids with submicron metallic oxide particles, Experimental Heat Transfer, 11 (1998), pp 151-170
- Launder, B. E., Spalding, D. B., The numerical computation of turbulent flows, Computer Methods in Applied Mechanics and Engineering, 3 (1974), 2, pp 269-289
- Henkes, et al., Comparison of the standard case for turbulent natural convection in a square enclosure, in a seminar on turbulent natural convection in enclosures: a computational and experimental benchmark study, Proceedings (R.A.W.M. Henkes and C.J. Hoogendoorn), Delft, Netherlands, 1992, 22, pp. 185-213
- Bilgen E., et al., Naturel convection in cavities with a thin fin on the hot wall, International Journal of Heat and Mass Transfer, 48 (2005), 17, pp 3493-3505
- Dixit, et al., Simulation of high Rayleigh number convection in a square cavity using the lattice Boltzmann method, International Journal of Heat and Mass Transfer, 49 (2006), pp. 727-739
- Baϊri, A., et al., 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, 49 (2008), pp. 771-782
- Lankhorst, A. M., Laminar and turbulent natural convection in cavities - numerical modelling and experimental validation, Ph.D. thesis, Technology University of Delft, Netherlands, 1991
- Ampofo, et al., Experimental benchmark data for turbulent natural convection in an air filled square cavity, International Journal of Heat and Mass Transfer, 46 (2003), pp. 3551-3572