Cooling performance of an impinging synthetic jet in a microchannel with nanofluids: An Eulerian approach

Numerical investigations of heat transfer enhancement in a three-dimensional micro-channel with a single synthetic jet were conducted using Al2O3-water, CuO-water and TiO2-water nanofluids. The effects of different types of nanoparticles at particle volume concentrations of 1%, 2% and 5% on the thermal performance in the micro-channel were examined. The numerical tool was validated against existing experimental data on the heat transfer characteristic of nanofluids in micro-channel. Heat transfer enhancement using nanofluids based on the Eulerian single-phase model was assessed for the cases with and without the operation of the synthetic jet. In general, the overall thermal performance was greatly influenced by the thermal conductivity and dynamic viscosity of the working nanofluids. The former corresponds to thermal enhancement by conduction whilst the latter corresponds to convective enhancement due to the periodic oscillation of the synthetic jet diaphragm. As the particle volume concentration of a nanofluid increased, effectiveness of the synthetic jet to provide convective cooling became poorer on account of higher viscosity. Nevertheless, in some cases, this can be overcome by the enhancement in thermal conductivity, depending on the Peclet number of the working fluid. Synthetic jet micmchannel with Al2O3-water nanofluid at phi = 5% showed the best overall cooling performance whereas TiO2-water nanofluid at phi = 5% failed to improve the thermal performance.

Automated summary

Numerical investigations were conducted on the heat transfer enhancement in a three-dimensional micro-channel using Al2O3-water, CuO-water and TiO2-water nanofluids with a single synthetic jet. Different types of nanoparticles at various concentrations were examined to assess their effects on thermal performance. The study found that the overall thermal performance was greatly influenced by the thermal conductivity and dynamic viscosity of the nanofluids, and the convective cooling effectiveness of the synthetic jet decreased with higher nanofluid viscosity, although this could be offset by an increase in thermal conductivity depending on the Peclet number.