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Thermally induced gas flows in ratchet channels with diffuse and specular boundaries
A net gas flow can be induced in the gap between periodically structured surfaces held at fixed but different temperatures when the reflection symmetry along the channel axis is broken. Such a situation arises when one surface features a ratchet structure and can be augmented by altering the boundar...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Nature Publishing Group
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5269730/ https://www.ncbi.nlm.nih.gov/pubmed/28128309 http://dx.doi.org/10.1038/srep41412 |
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author | Shahabi, Vahid Baier, Tobias Roohi, Ehsan Hardt, Steffen |
author_facet | Shahabi, Vahid Baier, Tobias Roohi, Ehsan Hardt, Steffen |
author_sort | Shahabi, Vahid |
collection | PubMed |
description | A net gas flow can be induced in the gap between periodically structured surfaces held at fixed but different temperatures when the reflection symmetry along the channel axis is broken. Such a situation arises when one surface features a ratchet structure and can be augmented by altering the boundary conditions on different parts of this surface, with some regions reflecting specularly and others diffusely. In order to investigate the physical mechanisms inducing the flow in this configuration at various Knudsen numbers and geometric configurations, direct simulation Monte Carlo (DSMC) simulations are employed using transient adaptive subcells for collision partner selection. At large Knudsen numbers the results compare favorably with analytical expressions, while for small Knudsen numbers a qualitative explanation for the flow in the strong temperature inhomogeneity at the tips of the ratchet is provided. A detailed investigation of the performance for various ratchet geometries suggests optimum working conditions for a Knudsen pump based on this mechanism. |
format | Online Article Text |
id | pubmed-5269730 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | Nature Publishing Group |
record_format | MEDLINE/PubMed |
spelling | pubmed-52697302017-02-01 Thermally induced gas flows in ratchet channels with diffuse and specular boundaries Shahabi, Vahid Baier, Tobias Roohi, Ehsan Hardt, Steffen Sci Rep Article A net gas flow can be induced in the gap between periodically structured surfaces held at fixed but different temperatures when the reflection symmetry along the channel axis is broken. Such a situation arises when one surface features a ratchet structure and can be augmented by altering the boundary conditions on different parts of this surface, with some regions reflecting specularly and others diffusely. In order to investigate the physical mechanisms inducing the flow in this configuration at various Knudsen numbers and geometric configurations, direct simulation Monte Carlo (DSMC) simulations are employed using transient adaptive subcells for collision partner selection. At large Knudsen numbers the results compare favorably with analytical expressions, while for small Knudsen numbers a qualitative explanation for the flow in the strong temperature inhomogeneity at the tips of the ratchet is provided. A detailed investigation of the performance for various ratchet geometries suggests optimum working conditions for a Knudsen pump based on this mechanism. Nature Publishing Group 2017-01-27 /pmc/articles/PMC5269730/ /pubmed/28128309 http://dx.doi.org/10.1038/srep41412 Text en Copyright © 2017, The Author(s) http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ |
spellingShingle | Article Shahabi, Vahid Baier, Tobias Roohi, Ehsan Hardt, Steffen Thermally induced gas flows in ratchet channels with diffuse and specular boundaries |
title | Thermally induced gas flows in ratchet channels with diffuse and specular boundaries |
title_full | Thermally induced gas flows in ratchet channels with diffuse and specular boundaries |
title_fullStr | Thermally induced gas flows in ratchet channels with diffuse and specular boundaries |
title_full_unstemmed | Thermally induced gas flows in ratchet channels with diffuse and specular boundaries |
title_short | Thermally induced gas flows in ratchet channels with diffuse and specular boundaries |
title_sort | thermally induced gas flows in ratchet channels with diffuse and specular boundaries |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5269730/ https://www.ncbi.nlm.nih.gov/pubmed/28128309 http://dx.doi.org/10.1038/srep41412 |
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