Experimental study on the effect of TiO2-water nanofluid on heat transfer and pressure drop

An experimental study performed to investigate the effect of nanoparticle volume fraction on the convection heat transfer characteristics and pressure drop of TiO2 (30 nm)-water nanofluids with nanoparticle volume fraction between 0.002 and 0.02, and Reynolds number between 8000 and 51,000. The experimental apparatus is a horizontal double tube counter-flow heat exchanger. It is observed that by increasing the Reynolds number or nanoparticle volume fraction, the Nusselt number increases. Meanwhile all nanofluids have a higher Nusselt number compared to distilled water. By use the nanofluid at high Reynolds number (say greater than 30,000) more power compared to low Reynolds number needed to compensate the pressure drop of nanofluid, while increments in the Nusselt number for all Reynolds numbers are approximately equal. Therefore using nanofluids at high Reynolds numbers compared with low Reynolds numbers, have lower benefits. (C) 2012 Elsevier Inc. All rights reserved.