Analysis of thermophoresis for separation of polystyrene microparticles in microfluidic devices
•The phenomenon of thermodiffusion is not valid as an application in separation processes for particles of 5 µm and larger under the gravitational field.•Convective flows of thermogravitational origin can be generated to mix different components in microdevices. We analysed the thermodiffusion pheno...
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Published in | International journal of heat and mass transfer Vol. 189; p. 122690 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Oxford
Elsevier Ltd
15.06.2022
Elsevier BV |
Subjects | |
Online Access | Get full text |
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Summary: | •The phenomenon of thermodiffusion is not valid as an application in separation processes for particles of 5 µm and larger under the gravitational field.•Convective flows of thermogravitational origin can be generated to mix different components in microdevices.
We analysed the thermodiffusion phenomenon both numerically and experimentally for size-based separation of polystyrene microparticles. For model validation, we followed previously published numerical studies using ANSYS Fluent 2020 R2 software. For our experimental analysis, we defined a new microchannel geometry that would separate at least two groups of particles (5 and 20 µm). We analysed the trajectory of the microparticles in the central channel of the microdevice under the following conditions: without a temperature gradient, with application of a thermal gradient parallel to the gravitational field (cooling from the bottom or top part), and generation of a temperature gradient perpendicular to the direction of the gravity force. Numerical and experimental results for these geometry and boundary conditions demonstrated that, under terrestrial conditions, 5 µm and larger microsized polystyrene particles cannot be separated by thermophoresis in flow because of the gravity force.
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ISSN: | 0017-9310 1879-2189 |
DOI: | 10.1016/j.ijheatmasstransfer.2022.122690 |