Abstract
An experimental analysis is made to measure the heat transfer, friction factor, thermal performance, and effectiveness of Cu/water nanofluids flow in a double-pipe U-bend heat exchanger. The metallic Cu nanoparticles are synthesized using chemical reduction method characterized with XRD technique. The stable Cu nanofluids were prepared by dispersing synthesized Cu nanoparticles in distilled water and then used for thermophysical properties and heat transfer evaluations. The experiments were conducted in the Reynolds number range from 3000 to 30,000 and in the particle volume concentrations of 0.1% and 0.3%. With the increase of particle volume concentrations and Reynolds number, the Nusselt number is enhanced. The increase of Nusselt number is of the order of 21.73% at particle volume concentration of 0.3% at a Reynolds number of 30,000 over water data. With the addition of Cu nanoparticles to the distilled water obviously the friction factor penalty is there. This penalty in friction factor is of the order of 1.141-fold over water data. The number of transfer units and effectiveness are directly proportional to the Reynolds number and volume concentrations. With the increase of volume concentrations and Reynolds number, the number of transfer units and effectiveness are increased. The experimental data is fitted based on the least-square method to obtain useful correlations.