Browsing by Author "Godi, N. Y."

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Forced convection heat transfer in micro heat sinks with square and circular configuration
(2023-06) Godi, N. Y.; Zhengwuvi, L. B.; Petinrin, M. O.
This paper reports the results of three-dimensional numerical optimisation of microchannel heat exchanger with square and circular cooling channels. The objective of the optimisation is to maximise the global thermal conductance or minimise global thermal resistance. Response surface optimisation methodology (RSM) is used in the numerical optimisation. A high-density heat flux (2.5×106𝑊/𝑚2) is imposed at the bottom surface of the unit cell microchannel and numerical simulation carried out using ANSYS Fluent commercial software package. The elemental volume and axial length 𝑁=10 𝑚𝑚 of the microchannel were all fixed, while the width was free to morph. The cooling technique employs single-phase water which flows through the rectangular block microchannel heat sink to remove the heat at the bottom of the microchannels in a forced convection laminar flow regime. The velocity of the fluid pumped across the microchannel axial length is the range 400≤𝑅𝑒𝑤≤500. Finite volume method (FVM) is used to descretised the computational domain and computational fluid dynamic (CFD) code employed to solve a series of governing equations. The effect of channel hydraulic diameter and Reynolds number of water-flow on peak wall temperature and minimised temperature are investigated and reported. The numerical results show that the microchannel with square cooling channel has the highest maximised global thermal conductance than the micro heat sink with circular configuration. The result of the numerical study agrees with what is in the open literature.
Heat transfer analysis in constructal designed microchannels with perforated micro fins
(The Institution of Engineers (India), 2023-04) Godi, N. Y.; Petinrin, M. O.
This paper documents 3-D numerical optimisation of combined microchannel heat sink with solid and perforated rectangular fins. Constructal design technique is deployed to construct a geometry with reduced material substrate and the effect on the heat transfer is examined. The goal of the study is to minimise the peak temperature or maximise global thermal performance. The axial length and volume of the microchannel are fixed, while the width is allowed to morph. The microelectronic device placed at the bottom of the combined heat sink emits heat flux q″ and the heat deposited at the bottom is removed using a single-phase fluid (water) of Reynolds number Re w in a forced convection laminar regime. The computational domain is descretised and the mathematical equations that govern the fluid flow and heat transfer are solved using the CFD code. Three unique cases were considered in this study. The influence of design parameters (channel width, external shape, and velocity of fluid applied) on the performance of the combined microchannel heat sink is discussed. The study revealed that the solid material substrates used in the manufacturing of the combined microchannel heat sink can be reduced without necessarily compromising the heat transfer at certain applied Re w . The global thermal conductance of the combined microchannel with no perforation on fins increases by 1.1% higher than the microchannel with 1-rectangular perforation on fins and 0.8% above the heat sink with 2-rectangular perforations on fins. The numerical results validation agrees with what is in the open literature.