Title: Combined convection nanofluid flow and heat transfer over microscale forward-facing step

Authors: A.Sh. Kherbeet; H.A. Mohammed; Kannan M. Munisamy; B.H. Salman

Addresses: Mechanical Engineering Department, College of Engineering, Universiti Tenaga Nasional, Jalan Ikram-Uniten, 43000 Kajang, Selangor, Malaysia ' Department of Thermofluids, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor Bahru, Malaysia ' Mechanical Engineering Department, College of Engineering, Universiti Tenaga Nasional, Jalan IkramUniten, 43000 Kajang, Selangor, Malaysia ' Mechanical Engineering Department, College of Engineering, Universiti Tenaga Nasional, Jalan Ikram-Uniten, 43000 Kajang, Selangor, Malaysia

Abstract: The laminar mixed convection flow of nanofluids over a 3D horizontal microscale forward-facing step (MFFS) was numerically investigated using a finite volume method. Various nanoparticle materials, such as SiO2, Al2O3, CuO, and ZnO, were dispersed in ethylene glycol as a base fluid with volume fractions in the range of 0 and 0.04. The duct has a step height of 650 µm. The downstream wall was heated with a uniform heat flux of 12 Watt, and the straight wall of the duct was kept at a constant temperature of 323 K. The Reynolds number value was maintained at 35. The results revealed that the SiO2 nanofluid had the highest Nusselt number, which increased with decreasing nanoparticle material density, increasing volume fraction and decreasing nanoparticles diameter. The static pressure and the wall shear stress increased with increasing particle volume fraction and decreasing particle diameter. Moreover, the nanoparticle volume faction, material and diameters had small effect on the skin friction coefficient.

Keywords: mixed convection; microscale forward-facing step; MFFS; heat transfer enhancement; nanofluids; laminar flow; finite volume method; static pressure; wall shear stress; particle volume fraction; particle diameter; nanoparticles; skin friction coefficient; nanotechnology.

DOI: 10.1504/IJNP.2014.062008

International Journal of Nanoparticles, 2014 Vol.7 No.1, pp.1 - 25

Received: 26 Apr 2013
Accepted: 30 Aug 2013

Published online: 30 Jun 2014 *

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