EXAMINATION OF THE VARIATION OF THERMAL PERFORMANCE WITH JET-PLATE DIST ANCE iN IMPINGING JET-CROSS FLOW CHANNELS HAVING FiN AND USED GRAPHENE OXIDE-WATER NANOFLUID

Abstract

With the developing technology, high performance and small voluıne electronic components can be produced; the temperatures of these elements exceed the limit values that can be considered safe. Current conventional heat transfer methods fall short of cooling these high­tech products. The heat transfer from electronic devices can be increased considerably with the impinging jet-cross flow. In this study, heat transfer from the crown and cavity pattemed surfaces was numerically analyzed by using water and 0.02% volumetric concentration GO (Graphene Oxide)-Water nanofluid in channels having differentjet-plate distances (H=3D and 4D) and fınless and fınned with impinging jet-cross flow. Numerical analysis was carried out steady and in three dimensions by using the Ansys-Fluent program with k-c turbulence model; the thermophysical properties of GO-Water nanofluid were obtained experimentally. Three models were positioned on the channels, taking into account the channel dimensions in the studies in the literature. When the fın angle is fıxed 90°; the distance of the fın in the channel from the impinging jet inlet is N=2D. A constant heat flux of 1000 W/m2 was applied to the model surfaces in the channels. The Re number range of both cross flow and impinging jet flow is 7000-11000. In order to prove the accuracy of the study, the results were compared with the results in the Nu number equation obtained by the experimental study in the literature and it was seen that they were quite compatible. The results of the study were investigated as the variations of the mean Nu number at different jet-plate distances and in the fınless-fınned state for each pattemed pattem surface and pattem row. In addition, velocity and temperature contour distributions for GO-Water nanofluid were evaluated in impinging jet-cross flow channels with both model surfaces for Re=l 1000 and in fın positions with H=3D and 4D jet­plate distances. However, the Performance Evaluation Nuınber (PEC) changes were determined for both model surface channels at different Re nuınbers and the pressure drop was interpreted against the Nu nuınber. In addition, the average Nu nuınber (Num) and surface temperature values (T m) for all three models in the channels were investigated. In the case of using nanofluids for all three crown and cavity model surfaces in H=3D and Re=ll000, the Num nuınbers are 64.78% and 56.56% higher than the fınless and water fluid, respectively; for H=4D, these values are 35.88% and 28.08% higher.