Abstract

Today, energy transfer enhancement techniques have received much attention for design and manufacturing more efficient systems in various industries such as automotive, computers, electronics, so forth. One way to achieve high-efficiency cooling systems is to use impingement jet cooling. In the present work, a numerical study has been conducted on nanofluid impingement jet in the vertical position to investigate the fluid flow characteristics and thermal energy transfer features. The working fluid in this study is a nanofluid with water- ethylene glycol mixture as base-fluid and nanoparticles of boehmite alumina. The flow is considered to be laminar, steady-state, two-dimensional, symmetrically axial, for which the finite volume method is used to solve the equations. The effect of Reynolds number variations, the volume fraction of nanoparticle, and different nanoparticle shapes (including spherical, plate, blade, cylindrical, and brick shapes) on thermos-physical features of the flow are studied. The results reveal that increasing Reynolds number and increasing the volume fraction of nanoparticles improves the thermal energy transfer rate. The highest Nusselt number, which leads to a maximum of energy transfer related to nanofluids with platelet and cylindrical nanoparticles, while the lowest thermal energy transfer rate is related to nanofluids containing spherical nanoparticles. Moreover, it is illustrated that nanofluids with platelets nanoparticles, because of their higher effective viscosity compares to other nanofluids, experience the highest pressure drop and those of with spherical nanoparticles show the lowest pressure drop.

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