Influence of texture shape and arrangement on thermo-hydraulic performance of the textured microchannels

Research output: Contribution to journalArticle

Authors

Colleges, School and Institutes

External organisations

  • Indian Institute of Technology, Bombay

Abstract

Textured superhydrophobic surfaces (TSS) are found to reduce flow friction in
microchannels due to velocity slip at liquid-gas interface. At the same time, the liquid-gas interface inhibits heat transfer in textured microchannels due to the low thermal conductivity of entrapped gas phase. Despite significant understanding on fluid flow and thermal transport on the TSS, the interplay of texture shape and arrangement on thermo-hydraulic performance has not investigated in detail hitherto. To this end, we have numerically investigated the
pressure-driven flow through textured microchannels with an aim to enhance the thermohydraulic performance. The effective slip length and temperature jump length were estimated as a function of flow and geometry parameters for three types of micropillar shapes viz., square, triangular and herringbone, decorated in microchannels in regular and staggered manner. Scaling relations for the effective slip length and temperature jump length have been shown to be valid for triangular and herringbone shaped micropillars at different flow and geometry related parameters. Herringbone shaped micropillars exhibit more flow friction and allow a significant heat transfer in microchannels within the parameter range investigated, followed by triangular and square shaped micropillars. Although the arrangement of textures in microchannels was found to affect the flow friction substantially, its effect on heat transfer was found to be marginal. Subsequently, the overall thermo-hydraulic performance was observed to be superior in regularly arranged herringbone shaped micropillars, at moderate to high constriction ratios and high Peclet numbers over the other texture shapes. The results presented in this work would serve as a useful guide to attain maximum thermo-hydraulic performance in textured microchannels.

Details

Original languageEnglish
JournalInternational Journal of Thermal Sciences
Publication statusAccepted/In press - 15 Oct 2019

Keywords

  • Effective slip length, microchannel, Nusselt number, pressure-driven flow, temperature jump length, superhydrophobic surfaces, textured surfaces