Author(s)

V. Bianco, O. Manca & S. Nardini

Abstract

In this paper the development of the laminar forced convection flow of a water– Al2O3 nanofluid in a circular tube submitted to a constant and uniform heat flux at the wall is numerically investigated in a transient regime. A single and twophase model (discrete particles model) is employed with either constant or temperature-dependent properties. The investigation is accomplished for a particle size equal to 100 nm. The convective heat transfer coefficient for nanofluids is greater than that of the base liquid. Heat transfer enhancement increases with the particle volume concentration, but it is accompanied by increasing wall shear stress values. Keywords: nanofluid, forced convection, transient numerical analysis. 1 Introduction Convective heat transfer enhancement is a continuous demand in many industrial heating or cooling equipment. An innovative technique for improving heat transfer by using ultra fine solid particles in the fluids has been used extensively during the last decade. Maxwell [1] showed the possibility of increasing thermal conductivity of a mixture by greater volume fraction of solid particles. These fluids, containing colloidal suspended nanoparticles, have been called nanofluids. Nowadays there is a fast growth of research activities in this heat transfer area, as recently reviewed for example in [2–4].

Keywords

nanofluid, forced convection, transient numerical analysis.