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

At current paper, heat transfer and pressure drop of TiO2-water nanofluid are investigated at nanoparticles volume fraction between 0.002 and 0.2, and Reynolds number between 8000 and 49000 experimetally in a double tube counter-flow heat exchanger. The results show that the Nusselt number and pressure drop of nanofluid increase by increasing nanoparticles volume fraction or Reynolds number, and the pressure drop of nanofluid is higher than the base fluid. The increament percentage in pressure drop of nanofluid compared with the base fluid is higher at lower Reynolds number. The enhancement value in the Nusselt number decreased with increasing the Reynolds number at 0.002 volume fraction. The Nusselt number increment value for nanoparticles volume fractions of 0.01 and 0.02 are identical for all Reynolds number. Therefore, more efficiency obtained at low Reynolds number by using nanofuid with 0.002-volume fraction, and at high Reynolds number for 0.01 and 0.02 volume fractions.