Heat transfer characteristics and entropy generation analysis in a plate heat exchanger using ethylene glycol and water mixture-based Al2O3 nanofluid

The present study aims to study the heat transfer and entropy generation analysis in a plate heat exchanger by dispersing Al2O3 nanoparticles into a water and ethylene glycol mixture (base fluid) of a 65:35 volume ratio. The study was carried out by varying the nanofluid concentration from 0.2 to 2 wt%. The effects of Peclet number and weight concentration of water:ethylene glycol-Al2O3 nanofluid on heat transfer characteristics and entropy generation were investigated. The nanofluid and distilled water were considered as a cold medium and hot medium on the plate heat exchanger, respectively, for the experimental study. The study showed considerable improvement in convective heat transfer coefficient and Nusselt number with the increase in nanofluid concentration. The study showed a 19.32% enhancement in overall heat transfer coefficient compared with base fluid at identical Peclet number. Pressure drop and pumping power were increased due to the addition of nanoparticles. Improved effectiveness was observed with the increase in concentration at higher Peclet numbers. Thermal entropy generation and friction entropy generation showed descending and ascending trends, respectively, for the considered weight concentration of nanofluid for the increased Peclet number. The Bejan number and entropy generation number demonstrated the roles of heat and friction in the entropy generation. A correlation was developed to predict the Nusselt number considering the experimental data. The prediction of the Nusselt number obtained from the present study showed good agreement with the experimental results.