Experimental investigation of the convective heat transfer characteristics of TiO2/distilled water nanofluids under constant heat flux boundary condition

This paper presents the experimental investigation of convective heat transfer characteristics of nanofluid containing TiO2 and distilled water inside a copper tube under laminar flow condition. Nanofluids with different particle weight concentration of 0.05, 0.1, 0.3 and 0.5 wt % are used in the present investigation. The effects of nanoparticles weight concentration on heat transfer coefficient and Nusselt number in the velocity range (0.1659–0.2322 m/s) under constant heat flux boundary conditions have been studied. The constant velocity criterion has been taken in order to get an accurate picture of convective heat transfer performance of nanofluids relative to base fluid. It is observed that the heat transfer coefficient increases with the increase in the particle weight concentration and flow velocity. Results revealed that the heat transfer coefficient increases from 29.93 to 50.11 % by increasing the concentration from 0.1 to 0.3 wt % as compared to distilled water in the given velocity range. The nanofluids show a decrease in heat transfer at higher concentration (0.5 wt %).