Flow optimization in a microchannel with vortex generators using genetic algorithm

A holistic approach to thermal-hydraulic design of 3D manifold microchannel heat sinks for energy-efficient cooling

We have investigated experimentally, for the first time at microscopic level, the growth of the deposit left around a drop of colloids drying on a solid surface (\"coffee stain effect\"). Direct observations show that there are several distinct phases of growth, the later ones exhibiting surprising pattern formations with spatial modulation of the deposit. In addition, fluorescence reveals that the initial growth phase is governed by a single length scale, increasing with time as t(23). We show that this exponent is a direct consequence of the divergence of evaporation near contact line evidenced by Deegan et al. We propose a simple ballistic model that allows us to calculate both this exponent and the prefactor, in agreement with yet available more complex descriptions. This model also opens the possibility to include effects neglected up to now.

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Evaporation of a sessile droplet: Inside the coffee stain

Lattice Boltzmann study of droplet evaporation on a heated substrate under a uniform electric field

Review article: Microscale evaporative cooling technologies for high heat flux microelectronics devices: Background and recent advances

Seeking maximum evaporative heat transfer, here we report the numerical optimization of an array of non-axisymmetric droplet shapes confined on hollow micropillars. Different shapes of droplets exhibit very different interfacial mass transport features, based on their different perimeter-to-area ratios and meniscus curvatures. Most recently, we have shown that, compared to spherical droplets, microdroplets confined on triangular micropillars can have up to a 71% higher heat transfer coefficient at a substrate temperature of 98°. Furthermore, to maximize the heat transfer coefficient, we optimized the shape of a triangular micropillar. In this study, building on our previous work, we use particle swarm optimization to identify the arrangement of arrays of micropillars that maximizes non-axisymmetric droplet evaporation. The optimized array of non-axisymmetric droplets, confined on pseudo-triangles, has a 3.5% higher heat transfer coefficient than an unoptimized array of reference non-axisymmetric pseudo-triangles. Compared to circular droplets on an orthogonal arrangement of micropillars, it has a 14.1% higher heat transfer coefficient.

Mun Mun Nahar

Papers

Review article: Microscale evaporative cooling technologies for high heat flux microelectronics devices: Background and recent advances

Design and Optimization Array of Micropillar Structures for Enhanced Evaporative Cooling of High-Powered Electronics