Study of forced convection of a nanofluid used as a heat carrier in a microchannel heat sink

摘要

In order to cool electronic equipment with a high efficiency we can use the flow of a nanofluid in a micro-channel heat sink. The paper reports the results of the study of the laminar forced convective heat transfer flow in such geometries. The study is numerical and was achieved using the mixture water /γ-Al2O3 as nanofluid and a single-phase approach. The geometrical configuration used in the computations contains two inlet jets. Calculations were first made with constant thermo-physical properties and then made using temperature-dependent thermo-physical properties. The volume fraction of nanoparticles in the nanofluid mixture was taken as 0% (i.e. water only), 1% and 4%. A three-dimensional conjugate heat transfer model was used and numerical simulations were based on a finite volume method. The results of thermal and hydrodynamic fields show that nanofluids can provoke an increase in the average and local Nusselt numbers, a decrease of bottom surface local temperature and a slight decrease of the shear stress on the wall, when compared to predictions using constant properties and nanoparticles free water. The results are discussed for nanoparticle diameters of 38 nm and a range of Reynolds number from 200 to 1200. Also the heat flux through the bottom surface of the heat sink was varied in the range q'' = 30W/cm~2 to 120 W/cm~2.