Constructal design of combined microchannel and micro pin fins for electronic cooling

Abstract

This paper presents a three-dimensional numerical study of steady, laminar, incompressible flow and forced convection heat transfer through a microchannel heat sink with micro pin fin inserts for both fixed and variable axial lengths. The objective of the study was to optimise the geometric configuration of an integrated microchannel and micro pin fins for different solid volumes so that the peak temperature in the configuration was minimised. The effect of the micro pin fins on the optimised microchannel was also investigated. The geometric optimisation of the integrated microchannel and micro pin fin was carried out using a computational fluid dynamics (CFD) code with a goal-driven optimisation tool subject to global constraints. The optimisation procedure was carried out in two steps. Firstly, the microchannel configuration was optimised without the micro pin fins inserted and the results were compared with similar work found in the open literature. This optimisation was carried out for both fixed and relaxed lengths. Thereafter, the integrated design of the microchannel and micro pin fins was optimised. The effect of the Bejan number on the solid volume fraction, channel aspect ratio and hydraulic diameter, pin fin aspect ratio, minimised peak temperature and maximized thermal conductance were reported. Results showed that as the Bejan number increased, the minimised peak temperature decreased. Also, the maximum thermal conductance increased with the optimised microchannel structure with three to six rows of micro pin fin inserts. Diminishing return set in when the number of rows of micro pin fin inserts was greater than three for the fixed length but for the relaxed length, as the number of rows increased, the results improved but when it exceeded six diminishing returns set in for a fixed solid volume of 0.9mm 3 . For each Bejan number used in this study, there was an optimum channel hydraulic diameter and aspect ratio, solid volume fraction and pin fin aspect ratio that satisfied the global objective.

Entropy generation and optimization of laminar convective heat transfer and fluid flow in a microchannel with staggered arrays of pin fin structure with tip clearance

“…Among all configurations under investigation, higher fin height scaled to channel height, lower fin width with spacing in a doubled size yields maximum number of fins in a row and better overall performance. Numerical simulation coupled with response surface method is implemented by Adewumi et al [26] for the peak temperature minimization in a microchannel with a single column of pin fins aligned in the flow direction. Increasing the dimensionless pressure difference -Bejan number minimizes the peak temperature of the microchannel.…”

A comparison of micro-structured flat-plate and cross-cut heat sinks for thermoelectric generation application

“…This type of heat sink has been interest of researchers for configuration optimization. To decrease the peak temperature and thermal conductance in a microchannel heat sink, Adewumi et al [2] presented a three-dimensional numerical study of an integrated design with micro pin fin inserts.…”

Influence of heating load on heat transfer characteristics in micro-pin-fin arrays

“…The structural parameters of each shape were optimized. Besides, Adewumi et al [14] also carried out an optimization of geometric configuration of an integrated micro-channel and micro pin fins for different solid volumes so that the peak temperature in the configuration was minimized. This optimization was carried out for both fixed and relaxed lengths.…”