Experimental heat transfer and pressure drop characteristics of Al2O3/water nanofluid in a circular tube with meshes and without meshes is reported in this paper. The SEM image of Al2O3 nanoparticles in base fluid showed that the particles are uniformly dispersed in base fluid and tiny agglomeration of nanoparticles are present. The experiments were conducted under turbulent conditions with varying flow rates. It is observed the heat transfer rates increased by about 7% and 13% for the case of tube with mesh insert compared to tube without mesh for the water and nanofluid, respectively. At the same time, it is also observed concluded that there is no remarkable increase in friction factor with the use of nanofluids which indicates that the dilute nanofluids having volume concentration about 0.1% can be used for enhancement of heat transfer with no additional pumping power
