Simulação numérica de nanofluidos escoando no interior de dutos retos

Abstract

This work aimed to show the enhancement of the convective heat transfer coefficient of nanofluids flowing in a straight pipe. For this purpose, the nanofluid was simulated numerically, both laminar and turbulent flow, and subjected to a boundary condition of constant heat flow through the wall, under the assumption that nanofluids have characteristics of single-phase fluids with modified properties. With the knowledge that the properties of nanofluids are function of the properties of both, nanoparticles and base fluid, was used a variety of combinations of these components in order to show a trend on the utilization of nanoparticles and base fluids of different natures. Thus, were used metallic nanoparticles (silver, copper and iron) and metallic oxides (alumina and copper oxide) dispersed in deionized water, ethylene glycol and poly-alpha-olefins. The properties of nanofluids were calculated by the conservative theoretical models for thermal conductivity and viscosity, and applying the rule of mixtures for density and specific heat, based on the properties of the components found in the literature. With these properties calculated, each nanofluid was simulated using the computational solver ANSYS®, at hydrodynamic and thermal conditions established, to obtain the corresponding fields for velocity, temperature and pressure. Finally, the results of simulation were processed to visualize the behavior of the convective heat transfer coefficient. Under the assumptions pre-defined, the highest enhancements of convective heat transfer of nanofluids were found with nanoparticles of metal oxides, relative to those of metallic nanoparticles.