Mechanical Engineering-Conference Papers
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Browsing Mechanical Engineering-Conference Papers by Author "Adewumi, O.O"
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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.
- ItemOpen AccessNumerical investigation into two-layered microchannel with varying axial length and temperature-dependent fluid properties(American Society of Mechanical Engineers, 2015-11) Adewumi, O.O; Bello-Ochende, T.; Meyer, J.PThis study numerically investigates the thermal performance of a two-layered microchannel heat sink with varying axial length, varying solid substrate aspect ratio (ratio of height to width of the silicon solid substrate) but with a fixed total volume constraint and water as the working fluid. The optimal geometry in terms of channel hydraulic diameter, channel aspect ratio and the solid substrate aspect ratio was selected based on the minimised peak temperature on the heated base of the solid substrate with a constant heat load of 100W. The optimal aspect ratio AR of the solid substrate was discovered to be 4 for all pressure drop range considered in this study but the optimal axial length shows a dependence on pressure drop. Results of the effect of varying axial length on surface heat flux, minimised thermal resistance and temperature variation on the heated base of the solid substrate were also presented and discussed.
- ItemOpen AccessNumerical optimization of forced convection of wall thickness of heated plates cooled using alumina-water nanofluid(Begel House Inc., 2018-08) Aduralere, T.T; Olakoyejo, O.T; Adewumi, O.O; Adelaja, A.O; Obayopo, S.O; Meyer, J.PThis paper applied constructal theory and design to present the numerical optimisation of forced convection of a rectangular plate placed between a heat source and a cooling fluid (Al2O3-Water) driven by forced convection at the upper surface. The main objective was to numerically optimise the configuration of the wall thickness using computational fluid dynamics (CFD) in such a way that the peak temperature was minimised from the solid to the fluid. An optimisation algorithm called Response Surface Optimisation within CFD code was applied in order to search for the optimal wall thickness configuration which improved thermal performance by minimising thermal resistance for a wide range of Reynolds numbers. The effect of varied Reynolds number and constant heat flux on the optimal geometry was reported. There was a unique optimal design geometry for a given value of Reynolds number. Results obtained show that an increase in the applied Reynolds number and the volume fraction of the cooling fluid leads to a decrease in minimum peak temperature.
- ItemOpen AccessTemperature variation on the heated base of a solid substrate cooled with different type of heat sinks(HEFAT, 2014-07) Adewumi, O.O; Bello-Ochende, T.; Meyer, J.PThree-dimensional numerical studies were carried out to investigate forced convection heat transfer and fluid flow in a solid substrate cooled using different types of micro heat sinks. The objective of this study is to investigate which heat sink type gives the lowest temperature variation on the heated base of the solid substrate which is being cooled. A low temperature variation indicates a low temperature gradient which, in practical application, improves the reliability of the electronic device. The different heat sinks considered are single microchannels, two-layer microchannels with parallel and counter-flow of fluid, single microchannels inserted with circularshaped micro pin fins and two-layer microchannels inserted with circular-shaped pin fins. All the heat sinks are geometrically optimised using a computational fluid dynamics code with a goal driven optimisation algorithm subject to global constraints. The thermal performance of the heat sinks considered in this study is based on two objectives namely, the minimisation of the peak temperature which results in maximisation of the thermal conductance and the lowest temperature variation on the heated base. The heat sink with the largest value of thermal conductance and lowest temperature variation on the heated base for the range of pressure drop considered is chosen as the best heat sink design. Numerical results of thermal performance for fixed axial length of the solid showed that cooling the solid substrate with the two-layer microchannel with counter-flow of fluid gave the lowest temperature difference at base of the solid substrate and also performed best in maximising thermal conductance at pressure drops of 20 and 30kPa.