LAUSR

Abstract Three-dimensional heat transfer of nanofluids in microchannels with hydrophilic, hydrophobic and, superhydrophobic surfaces were studied using numerical simulation. For this purpose, Navier Stokes and energy equations were solved using the finite volume method. The flow Reynolds numbers were in the range of 40–500. Water/Al2O3 and Water/TiO2 were considered as coolant fluids. By applying hydrophobic surfaces, the flow pressure drop decreased, especially for the case of superhydrophobic walls. Microchannel with hydrophobic walls required 12% less pumping power than those with hydrophilic walls. The superhydrophobic wall caused a 66% reduction in the required pumping power. The use of nanofluids as a coolant improved the thermal performance. The results showed that the simultaneous use of the hydrophobic surface and the addition of nanoparticles could increase the performance evaluation criterion to 1.75 at Re = 400 and caused the lowest substrate temperatures. In addition, for the flows with Re > 150, applying the superhydrophobic walls was more effective than the usage of nanofluids as coolants with conventional walls.