Competing effects of buoyancy-driven and electrothermal flows for Joule heating-induced transport in microchannels
Ionic fluids subjected to externally applied electric fields experience Joule heating, which increases with the increased electric field and ionic conductivity of the medium. Temperature gradients induced by Joule heating can create buoyancy-driven flows produced by local density changes, as well as...
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| Format: | Article |
| Language: | English |
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Cambridge University Press
2023-01-01
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| Series: | Flow |
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| Online Access: | https://www.cambridge.org/core/product/identifier/S2633425923000193/type/journal_article |
| _version_ | 1797773125141659648 |
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| author | Mohammad K. D. Manshadi Ali Beskok |
| author_facet | Mohammad K. D. Manshadi Ali Beskok |
| author_sort | Mohammad K. D. Manshadi |
| collection | DOAJ |
| description | Ionic fluids subjected to externally applied electric fields experience Joule heating, which increases with the increased electric field and ionic conductivity of the medium. Temperature gradients induced by Joule heating can create buoyancy-driven flows produced by local density changes, as well as electrothermal transport due to the temperature-dependent variations in fluid permittivity and conductivity. This manuscript considers Joule heating-induced transport in microchannels by a pair of electrodes under alternating current electric fields. Resulting buoyancy-driven and alternating current electrothermal (ACET) flows are investigated theoretically, numerically and experimentally. Proper normalizations of the governing equations led to the ratio of the electrothermal and buoyancy velocities, as a new non-dimensional parameter, which enabled the construction of a phase diagram that can predict the dominance of ACET and buoyancy-driven flows as a function of the channel size and electric field. Numerical results were used to verify the phase diagram in various height microchannels for different ionic conductivity fluids and electric fields, while the numerical results were validated using the micro-particle-image velocimetry technique. The results show that ACET flow prevails when the channel dimensions are small, and the electric potentials are high, whereas buoyancy-driven flow becomes dominant for larger channel heights. The present study brings insights into Joule heating-induced transport phenomena in microfluidic devices and provides a pathway for the design and utilization of ACET-based devices by properly considering the co-occurring buoyancy-driven flow. |
| first_indexed | 2024-03-12T22:01:48Z |
| format | Article |
| id | doaj.art-2563932a315444d4a6375222b7ac525d |
| institution | Directory Open Access Journal |
| issn | 2633-4259 |
| language | English |
| last_indexed | 2024-03-12T22:01:48Z |
| publishDate | 2023-01-01 |
| publisher | Cambridge University Press |
| record_format | Article |
| series | Flow |
| spelling | doaj.art-2563932a315444d4a6375222b7ac525d2023-07-25T06:33:25ZengCambridge University PressFlow2633-42592023-01-01310.1017/flo.2023.19Competing effects of buoyancy-driven and electrothermal flows for Joule heating-induced transport in microchannelsMohammad K. D. Manshadi0Ali Beskok1https://orcid.org/0000-0002-8838-5683Mechanical Engineering Department, Southern Methodist University, Dallas, TX 75275, USAMechanical Engineering Department, Southern Methodist University, Dallas, TX 75275, USAIonic fluids subjected to externally applied electric fields experience Joule heating, which increases with the increased electric field and ionic conductivity of the medium. Temperature gradients induced by Joule heating can create buoyancy-driven flows produced by local density changes, as well as electrothermal transport due to the temperature-dependent variations in fluid permittivity and conductivity. This manuscript considers Joule heating-induced transport in microchannels by a pair of electrodes under alternating current electric fields. Resulting buoyancy-driven and alternating current electrothermal (ACET) flows are investigated theoretically, numerically and experimentally. Proper normalizations of the governing equations led to the ratio of the electrothermal and buoyancy velocities, as a new non-dimensional parameter, which enabled the construction of a phase diagram that can predict the dominance of ACET and buoyancy-driven flows as a function of the channel size and electric field. Numerical results were used to verify the phase diagram in various height microchannels for different ionic conductivity fluids and electric fields, while the numerical results were validated using the micro-particle-image velocimetry technique. The results show that ACET flow prevails when the channel dimensions are small, and the electric potentials are high, whereas buoyancy-driven flow becomes dominant for larger channel heights. The present study brings insights into Joule heating-induced transport phenomena in microfluidic devices and provides a pathway for the design and utilization of ACET-based devices by properly considering the co-occurring buoyancy-driven flow.https://www.cambridge.org/core/product/identifier/S2633425923000193/type/journal_articleJoule heatingAC electrothermal flowBuoyancy driven flowNon-dimensional equations |
| spellingShingle | Mohammad K. D. Manshadi Ali Beskok Competing effects of buoyancy-driven and electrothermal flows for Joule heating-induced transport in microchannels Flow Joule heating AC electrothermal flow Buoyancy driven flow Non-dimensional equations |
| title | Competing effects of buoyancy-driven and electrothermal flows for Joule heating-induced transport in microchannels |
| title_full | Competing effects of buoyancy-driven and electrothermal flows for Joule heating-induced transport in microchannels |
| title_fullStr | Competing effects of buoyancy-driven and electrothermal flows for Joule heating-induced transport in microchannels |
| title_full_unstemmed | Competing effects of buoyancy-driven and electrothermal flows for Joule heating-induced transport in microchannels |
| title_short | Competing effects of buoyancy-driven and electrothermal flows for Joule heating-induced transport in microchannels |
| title_sort | competing effects of buoyancy driven and electrothermal flows for joule heating induced transport in microchannels |
| topic | Joule heating AC electrothermal flow Buoyancy driven flow Non-dimensional equations |
| url | https://www.cambridge.org/core/product/identifier/S2633425923000193/type/journal_article |
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