Heat transfer studies in a plate heat exchanger using Fe2O3-water-engine oil nanofluid

Abstract

Improving the heat transfer performance of conventional fluid creates significant energy savings in process Industries. In this aspect, an experimental study was performed to evaluate the heat transfer performance of Fe2O3-water (W)-engine oil (EO) nanofluid at different concentrations and hot fluid inlet temperatures in a plate heat exchanger. Experiments were conducted by mixing Fe2O3 nanoparticles (45 nm) in a W-EO mixture base fluid with volume fractions of 5% EO + 95% W and 10% EO +90% W. The main aim of the present study was to assess the impacts of nanoparticle volume fraction and hot fluid inlet temperature variations on the heat transfer performance of the prepared nanofluid. The convective heat transfer coefficient, Reynolds, Prandtl, and Nusselt numbers were determined based on the experimental results. The result shows that at the hot fluid inlet temperature of 75 ?C, the increase in Nusselt number and convective heat transfer coefficient are optimum at 0.9 vol. % nanoparticle for both the base fluid mixtures. The increase in heat transfer coefficient is because of the Brownian motion (increasing thermal conductivity) effect, motion caused by the temperature gradient (Thermo-phoretic), and motion due to concentration gradient (Osmophoretic). If the volume fraction of the nanoparticle increases, then the Reynolds number increment is higher than the Prandtl number decrement, which augments the Nusselt number and convective heat transfer coefficient.