One-way flow over uniformly heated U-shaped bodies driven by thermal edge effects
Abstract The thermal edge flow is a gas flow typically induced near a sharp edge (or a tip) of a uniformly heated (or cooled) flat plate. This flow has potential applicability as a nonmechanical pump or flow controller in microelectromechanical systems (MEMS). However, it has a shortcoming: the ther...
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2022-02-01
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| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-022-05534-y |
| _version_ | 1798023855347859456 |
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| author | Satoshi Taguchi Tetsuro Tsuji |
| author_facet | Satoshi Taguchi Tetsuro Tsuji |
| author_sort | Satoshi Taguchi |
| collection | DOAJ |
| description | Abstract The thermal edge flow is a gas flow typically induced near a sharp edge (or a tip) of a uniformly heated (or cooled) flat plate. This flow has potential applicability as a nonmechanical pump or flow controller in microelectromechanical systems (MEMS). However, it has a shortcoming: the thermal edge flows from each edge cancel out, resulting in no net flow. In this study, to circumvent this difficulty, the use of a U-shaped body is proposed and is examined numerically. More specifically, a rarefied gas flow over an array of U-shaped bodies, periodically arranged in a straight channel, is investigated using the direct simulation Monte-Carlo (DSMC) method. The U-shaped bodies are kept at a uniform temperature different from that of the channel wall. Two types of U-shaped bodies are considered, namely, a square-U shape and a round-U shape. It is demonstrated that a steady one-way flow is induced in the channel for both types. The mass flow rate is obtained for a wide range of the Knudsen numbers, i.e., the ratio of the molecular mean free path to the characteristic size of the U-shape body. For the square-U type, the direction of the overall mass flow is in the same direction for the entire range of the Knudsen numbers investigated. For the round-U type, the direction of the total mass flux is reversed when the Knudsen number is moderate or larger. This reversal of the mass flow rate is attributed to a kind of thermal edge flow induced over the curved part of the round-U-shaped body, which overwhelms the thermal edge flow induced near the tip. The force acting on each of the bodies is also investigated. |
| first_indexed | 2024-04-11T17:53:17Z |
| format | Article |
| id | doaj.art-740d929684604bdcb495265bae8af17b |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-04-11T17:53:17Z |
| publishDate | 2022-02-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-740d929684604bdcb495265bae8af17b2022-12-22T04:10:59ZengNature PortfolioScientific Reports2045-23222022-02-0112111710.1038/s41598-022-05534-yOne-way flow over uniformly heated U-shaped bodies driven by thermal edge effectsSatoshi Taguchi0Tetsuro Tsuji1Department of Advanced Mathematical Sciences, Graduate School of Informatics, Kyoto UniversityDepartment of Advanced Mathematical Sciences, Graduate School of Informatics, Kyoto UniversityAbstract The thermal edge flow is a gas flow typically induced near a sharp edge (or a tip) of a uniformly heated (or cooled) flat plate. This flow has potential applicability as a nonmechanical pump or flow controller in microelectromechanical systems (MEMS). However, it has a shortcoming: the thermal edge flows from each edge cancel out, resulting in no net flow. In this study, to circumvent this difficulty, the use of a U-shaped body is proposed and is examined numerically. More specifically, a rarefied gas flow over an array of U-shaped bodies, periodically arranged in a straight channel, is investigated using the direct simulation Monte-Carlo (DSMC) method. The U-shaped bodies are kept at a uniform temperature different from that of the channel wall. Two types of U-shaped bodies are considered, namely, a square-U shape and a round-U shape. It is demonstrated that a steady one-way flow is induced in the channel for both types. The mass flow rate is obtained for a wide range of the Knudsen numbers, i.e., the ratio of the molecular mean free path to the characteristic size of the U-shape body. For the square-U type, the direction of the overall mass flow is in the same direction for the entire range of the Knudsen numbers investigated. For the round-U type, the direction of the total mass flux is reversed when the Knudsen number is moderate or larger. This reversal of the mass flow rate is attributed to a kind of thermal edge flow induced over the curved part of the round-U-shaped body, which overwhelms the thermal edge flow induced near the tip. The force acting on each of the bodies is also investigated.https://doi.org/10.1038/s41598-022-05534-y |
| spellingShingle | Satoshi Taguchi Tetsuro Tsuji One-way flow over uniformly heated U-shaped bodies driven by thermal edge effects Scientific Reports |
| title | One-way flow over uniformly heated U-shaped bodies driven by thermal edge effects |
| title_full | One-way flow over uniformly heated U-shaped bodies driven by thermal edge effects |
| title_fullStr | One-way flow over uniformly heated U-shaped bodies driven by thermal edge effects |
| title_full_unstemmed | One-way flow over uniformly heated U-shaped bodies driven by thermal edge effects |
| title_short | One-way flow over uniformly heated U-shaped bodies driven by thermal edge effects |
| title_sort | one way flow over uniformly heated u shaped bodies driven by thermal edge effects |
| url | https://doi.org/10.1038/s41598-022-05534-y |
| work_keys_str_mv | AT satoshitaguchi onewayflowoveruniformlyheatedushapedbodiesdrivenbythermaledgeeffects AT tetsurotsuji onewayflowoveruniformlyheatedushapedbodiesdrivenbythermaledgeeffects |