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ISSN Online: 2379-1748
8th Thermal and Fluids Engineering Conference (TFEC)
HEAT TRANSFER ENHANCEMENT OF A COIL HEAT EXCHANGER USING NANOFLUIDS WITH METAL OXIDE NANOPARTICLES DISPERSED IN WATER, OIL AND EHTYLENE GLYCOL
Abstract
In recent years, nanofluids have been used to improve the rate of heat transfer in heat exchangers. In this study numerical simulations were performed to evaluate the effect on the heat transfer in a Coil Heat Exchanger (CHE) due to the variation of geometry, Dean Number and type of nanofluid. The numerical model assumed thermophysical properties dependent on the base fluid, type and concentration of nanoparticle and fluid temperature. Seven geometries of CHE with different coil curvature and pitch were considered in the simulation. Nanofluids with nanoparticles of Al2O3, CuO and TiO2 dispersed in water, oil and ethylene glycol at concentration of 0.5%, 1% and 2% by weight were employed as a working fluid. The average Nusselt (Nu) number of CHE increased with higher Dean Numbers and lower curvature ratios. For higher concentrations of nanofluid, the Nusselt Number increased but a lower rate than with the geometry and Dean Number. A general correlation to predict the Nusselt Number for a variety of nanofluids in function of the Reynolds Number, curvature ratio and nanoparticle concentration was developed for a range of Prandtl numbers of 3.5 to 350.