## THERMAL SCIENCE

International Scientific Journal

### IMPACT OF SURFACE TEXTURE ON NATURAL CONVECTION BOUNDARY LAYER OF NANOFLUID

**ABSTRACT**

Heat transfer characteristics are investigated in natural convection flow of water-based nanofluid near a vertical rough wall. The analysis considers five different nanoparticles, namely, silver (Ag), copper (Cu), alumina (Al2O3), magnetite (Fe3O4)and silica (SiO2). The concentration has been limited between 0-20% for all types of nanoparticle. The governing equations are modeled using the Boussinesq approximation and Tiwari and Das model is utilized to represent the nanofluid. The analysis examines the effects of the nanoparticle volume fraction, the type of nanofluid and the wavy surface geometry parameter on the skin friction and Nusselt number. It is observed that for a given nanofluid the skin friction and Nusselt number can be maximized via an appropriate tuning of the wavy surface geometry parameter along with the selection of suitable nanoparticle. Particular to this study copper (Cu) is observed to be more productive towards the flow and heat transfer enhancement. In total the metallic oxides are found to be less beneficial as compared to the pure metals.

**KEYWORDS**

PAPER SUBMITTED: 2015-10-08

PAPER REVISED: 2016-04-08

PAPER ACCEPTED: 2016-05-17

PUBLISHED ONLINE: 2016-05-30

**THERMAL SCIENCE** YEAR

**2018**, VOLUME

**22**, ISSUE

**1**, PAGES [157 - 169]

- Choi, S.U. S., Enhancing Thermal Conductivity of Fluids with Nanoparticles, ASME, FED, 132 (1995), 66, pp. 99-105
- Masuda, H., Ebata, A., Teramae, K., Hishinuma, N., Alteration of Thermal Conductivity and Viscosity of Liquid by Dispersing Ultra-Fine Particles. Netsu Bussei, 7 (1993), pp. 227-233
- Khanafer, K., Vafai, K., Lightstone, M., Buoyancy-Driven Heat Transfer Enhancement in a Two-Dimensional Enclosure Utilizing Nanofluids. Int. J. Heat Mass Transf., 46 (2003), pp. 3639-3653
- Pohlhausen, E., Der Wareastausch Zwischen Festen Kor- penn und Flussigkeiten mit Kleineer Reibung und Klein- erwarmeletung. Zeitschrift für Angewandte Mathematik und Mechanik, 2 (1921), pp. 115-121
- Ostrach, S., An Analysis of Laminar Free Convective Flow and Heat Transfer about a Flat Plate Parallel to Direction of the Generating Body Force. NASA (1953), (1111).
- Yao, L. S., Natural Convection along a Vertical Wavy Surface. ASME J. Heat Transf., 105 (1983), pp. 465-468
- Moulic, S. G., Yao, L. S., Natural Convection along a Wavy Surface with Uniform Heat Flux, ASME J. Heat Transf., 111 (1989), pp. 1106-1108
- Molla, M. M., Hossain, M. A., Yao, L. S., Natural Convection Flow along a Vertical Wavy Surface with Heat Generation/Absorption, Int. J. Therm. Sci., 43 (2004), pp. 157-163
- Rees, D.A. S., Pop, I., A Note on a Free Convection along a Vertical Wavy Surface in a Porous Medium, ASME J. of Heat Transf., 115 (1994), pp. 505-508
- Hossain, M. A., Rees, D.A. S., Combined Heat and Mass Transfer in Natural Convection Flow from a Vertical Wavy Surface, Acta Mechanica, 136 (1999), pp. 133-141
- Cheng, C. Y, Natural Convection Heat and Mass Transfer near a Vertical Wavy Surface with Constant Wall Temperature and Concentration in a Porous Medium. Int. Commun. Heat and Mass Transf., 27 (2000), pp. 1143-1154
- Siddiqa, S., Hossain, M. A., Saha, S. C., Natural Convection Flow with Surface Radiation along a Vertical Wavy Surface. Num. Heat Transf., 64 (2013), pp. 400-415
- Molla, M. M., Hossain, M. A., Yao, L. S., Natural Convection Flow along a Vertical Wavy Surface with Uniform Surface Temperature in Presence of Heat Generation/Absorption. Int. J. Therm. Sci.,43 (2004), 2, pp. 157-163
- Javed, T., Mehmood, Z., Siddique, A.M., Pop, I., Effects of uniform magnetic field on the natural convection of Cu-water nanofluid in a triangular cavity, Int. J. Num. Meh. Heat Fliud Flow, (2016) DOI 10.1108/HFF-10-2015-0448
- Mustafa, I., Javed, T. and Majeed, A., Magnetohydrodynamic (MHD) mixed convection stagnation point flow of a nanofluid over a vertical plate with viscous dissipation, Canad. J. Phy., 93(11) (2015) pp.1365-1374
- Ghaffari, A., Javed,T., Labropuluo, F., Oblique stagnation point flow of a non-Newtonian nanofluid over stretching surface with radiation, A numerical study, Therm. Sci., (2015), DOI: 10.2298/TSCI150411163G
- Tiwari, R. K., Das, M. K., Heat Transfer Augmentation in a Two-Sided Lid-Driven Differentially Heated Square Cavity Utilizing Nanofluids, Int. J. Heat Mass Transf., 50 (2007), pp. 2002-2018
- Maxwell G. J. C., Colours in Metal Glasses and in Metallic Films. Philos. Trans. R. Soc. Lond. A, 203 (1904), pp. 385-42
- Cebeci, T., Bradshaw, P., Physical and Computational Aspects of Convective Heat Transfer, Springer New York, 1988
- Cebeci, T., Cousteix, J., Modeling and Computing of Boundary-Layer Flows Laminar, Turbulent and Transitional Boundary Layers in Incompressible and Compressible Flows, Springer, 2005
- Na, T. Y., Computational Methods in Engineering Boundary Value Problems, Academic Press New York, 1979
- Alim, M. A., Karim, M. R., Akand, M. M., Heat Generation Effects on Magnetohydrodynamic(MHD) Natural Convection Flow along a Vertical Wavy Surface with Variable Thermal Conductivity, A. J. of Comput. Math., 2 (2012), pp. 42-50
- Hossain, M. A, Kabir, S., Rees, D.A. S., Natural Convection of Fluid with Temperature Dependent Viscosity from Heated Vertical Wavy Surface, ZAMP, 53 (2002), pp. 48-52
- Kabir, K. H., Alim, M. A, Andallah, L. S., Effect of Viscous Dissipation on MHD Natural Convection Flow along a Uniformly Heated Vertical Wavy Surface, J. Theo. and App. Phy., 7 (2013), pp. 1-8
- Bachok, N., Ishak, A., Pop I., Flow and Heat Transfer Characteristics on a Moving Plate in a Nanofluid, Int. J. Heat Mass Transfer, 55 (2012), pp. 642-648