Experimental investigation of hydrodynamics and heat transfer characteristics of γ-Al2O3/water under laminar flow inside a horizontal tube

In the present study, hydrodynamics and heat transfer characteristics of gamma-Al2O3 nanoparticles inside a circular tube in laminar flow with constant heat flux was investigated. For this purpose, gamma-Al2O3 nanoparticles with 15 nm diameter and distilled water as base fluid were used. The primary objective is to evaluate the effect of different volume concentration on convective heat transfer. In addition, the effect of volume concentration is also studied on friction factor. Increasing the particle volume fraction leads to enhancement of convective heat transfer coefficient. Results revealed that the average heat transfer coefficient increased 6.8% with 0.5% volume concentration and enhanced 19.1% at 1% volume concentration in comparison with distilled water. More the heat flux is more the heat transfer coefficient is. From the results, there is no significant change of friction factor for nanofluids in comparison with base fluid. A new correlation was proposed based on our experimental observation in order to present a deep insight into the current issue. (C) 2012 Published by Elsevier Masson SAS.