The effects of nanofluid on thermophysical properties and heat transfer characteristics of a plate heat exchanger

Improving heat exchanger's performance by increasing the overall heat transfer as well as minimising pressure drop is one of the promising fields of research to focus on. Nanofluids with higher thermal conductivity and better thermophysical properties can be applied in heat exchanger to increase the heat transfer rate. In the present study SiO2, TiO2 and Al2O3 are applied in a plate heat exchanger and the effects on thermophysical properties and heat transfer characteristics are compared with the base fluid. Since it is desired to minimize the pressure drop, the influence of nanofluid application on pressure drop and entropy generation is investigated. It is concluded that the thermal conductivity, heat transfer coefficient and heat transfer rate of the fluid increase by adding the nanoparticles and TiO2 and Al2O3 result in higher thermophysical properties in comparison with SiO2. The highest overall heat transfer coefficient was achieved by Al2O3 nanofluid, which was 308.69 W/m(2).K in 0.2% nanoparticle concentration. The related heat transfer rate was improved around 30% compared to SiO2 nanofluid. In terms of pressure drop, SiO2 shows the lowest pressure drop, and it was around 50% smaller than the pressure drop in case of using TiO2 and Al2O3. (c) 2013 Elsevier Ltd. All rights reserved.