Mechanical Engineering-Conference Papers
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Browsing Mechanical Engineering-Conference Papers by Subject "Heat transfer enhancement"
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- ItemOpen AccessComparison between the thermal performance of single and two-layer microchannels inserted with micro pin fins(Begel House Inc., 2014-08) Adewumi, O.O; Bello-Ochende, T.; Meyer, J.PThis paper presents a three-dimensional numerical study of steady, laminar, incompressible flow and forced convection heat transfer through a two-layer rectangular microchannel heat sink inserted with pin fins. The objective of the study was to optimise the geometric configuration of the combined two layer microchannel heat sink with micro pin fin inserts for a fixed solid volume so that the peak temperature within the configuration is minimised. The geometric optimisation of the microchannel was carried out using a computational fluid dynamic code with a goal driven optimization workbench tool subject to global constraints. Effects of pressure drop on the minimised peak temperature and maximum thermal conductance for the fixed solid volume were reported. The thermal performance of the single and two-layer microchannel heat sink inserted with micro pin fins based on the minimised peak temperature and maximised global thermal conductance were compared and their results were reported. For a constant solid volume of 0.9mm3 and fixed length of 10mm, it was observed that while the performance of the single microchannel was improved with the micro pin fins, it was not the case with the two-layer microchannel. These results showed that inserting pin fins in a two-layer microchannel does not enhance the heat transfer when the length of the solid substrate is fixed. The thermal performance of the combined design when the axial length of the solid substrate was relaxed was also reported.
- ItemOpen AccessGeometric optimisation of multi-layered microchannel heat sink with different flow arrangements(Begel House Inc., 2014-08) Adewumi, O.O; Bello-Ochende, T.; Meyer, J.PThis paper presents the use of the constructal design technique to optimise the geometry of a multilayered microchannel heat sink. The objective of this numerical investigation was to minimise the peak temperature of the solid substrate into which the microchannel was embedded. Parallel and counter-flow of fluid through the microchannel is considered in this study. The geometric optimisation of the microchannel was carried out using a computational fluid dynamic (CFD) code with a goal-driven optimisation workbench tool subject to global constraints. Optimal dimensions of the multi-layered microchannel in terms of the channel hydraulic diameter, channel aspect ratio, solid volume fraction, for the fixed solid volume that minimised the peak temperature and maximised the thermal conductance were reported. Results showed that as the pressure drop increased, the minimised peak temperature decreased and the maximum thermal conductance increased. When the number of layers of the microchannel was increased from two to three, the results of the thermal conductance became worse. For the design parameters used in this study, the two-layered stack microchannel with counter-flow arrangement was the best design in minimising the peak temperature and maximising the thermal conductance when the pressure drop was between 20 and 60kPa.