COOLING OF HEATED SURFACES IN COMBINED JET FLOW CHANNELS WITH DIFFERENT FIN POSITIONS AND SiO2-WATER NANOFLUID

Abstract

The increase in energy prices around the world negatively affects production costs, especially in the heat-intensive industry. However, the increase in the amount of heat production per unit volume in electronic devices whose dimensions have decreased with the development of technology is an undesirable situation for the progress process in this sector. The co-application of cross-flow-impinging jet flow as a combined jet flow increases the cooling capacity of high-temperature surfaces. In this study, heat transfer from trapezoidal and hollow model surfaces and flow structures in channels were investigated numerically using water and SiO2-Water nanofluids in H=4D height channels with combined jet flow with 30o and 60o angled fins. The fins were located at N=D and N=2D positions from the impinging jet inlet. The fin length (K) is 2D. Numerical analysis was carried out by solving energy and Navier-Stokes equations with the k- turbulence model using the Ansys-Fluent program in three-dimensional and steady. While the upper and lower surfaces of the fin and channel are adiabatic; model surfaces have a constant heat flux of 1000 W/m2. The Reynolds number range studied for fluids is 7000-11000. Thermophysical properties of SiO2-Water nanofluid with 2% volumetric concentration were obtained with the help of equations found in the literature. The results of the study were compared with the correlation obtained as a result of the experimental study in the literature and the results were found to be compatible. The results were evaluated as the variation of the mean Nu number for each trapezoidal and hollow model surface in the channels. However, velocity-streamline and temperature contour distributions of SiO2-Water nanofluid were visualized for different fin angles (30o and 60o) and placements (N=D and N=2D) at Re=11000. Nuort and Tort values were analyzed comparatively when water and SiO2-Water nanofluid were used for all model surfaces in the channels at different values of Reynolds number and N=D and N=2D fin positions. As a result, 46.65% and 51.27% increases in Nuort value for trapezoidal and hollow model surfaces, respectively, were obtained compared to water fluid when N=2D fin position and SiO2-Water nanofluid were used for Re=11000.