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A computational fluid dynamics (CFD) model investigating the heat transfer convective coefficient of the upstream face, the upstream face and the tube face, and the upstream face, tube face, and leeward face of a perforated sheet was developed. This model was based on the hexagonally shaped flow pattern that exists around each of the holes in a perforated sheet of a certain pitch to diameter ratio. The CFD model used in the investigation of the convective heat transfer coefficient involved a single hole in a thin hexagonally shaped sheet with appropriate boundary conditions. Through a series of models varying the inlet velocity, hole diameter, and the plate temperature and then solving for the exit temperature the convective coefficient could be obtained. After obtaining the convective coefficient, the Nusselt number was calculated. These values were then plotted against the Reynolds number and an equation for the line was obtained of the form: Nu=C1·ReC2(1)

In this paper, experimental investigation has been performed to characterize the heat transfer behavior of CuO–water and ZnO–water nanofluids. Nanofluids containing different volume percent (vol %) of nanoparticle concentrations flowed over a flat copper plate under a constant heat load. The constant heat flux was maintained using evenly placed cartridge heaters. The heat transfer coefficients of nanofluids were measured and compared with the results obtained from identical experiments performed with de-ionized (DI) water. In order to thoroughly characterize the nanofluids, nanoparticle size was investigated to inspect for possible agglomeration. The particle size was measured by using both a transmission electron microscope (TEM) and a dynamic light scattering system (DLS). Enhancement of convective heat transfer of nanofluids was 2.5–16% depending on the nanoparticle concentrations and Reynolds number. The plausible mechanisms of the enhanced thermal performance of CuO and ZnO nanofluids will be discussed in the following paper.