Capillary-Limited Evaporation From Well-Defined Microstructured Surfaces
Thermal management is increasingly becoming a bottleneck for a variety of high power density applications such as integrated circuits, solar cells, microprocessors, and energy conversion devices. The performance and reliability of these devices are usually limited by the rate at which heat can be re...
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| Format: | Article |
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American Society of Mechanical Engineers
2019
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| Online Access: | http://hdl.handle.net/1721.1/120516 https://orcid.org/0000-0002-0258-0745 https://orcid.org/0000-0001-7045-1200 |
| _version_ | 1826206543707635712 |
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| author | Adera, Solomon Raj, Rishi Wang, Evelyn |
| author2 | Massachusetts Institute of Technology. Department of Mechanical Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Mechanical Engineering Adera, Solomon Raj, Rishi Wang, Evelyn |
| author_sort | Adera, Solomon |
| collection | MIT |
| description | Thermal management is increasingly becoming a bottleneck for a variety of high power density applications such as integrated circuits, solar cells, microprocessors, and energy conversion devices. The performance and reliability of these devices are usually limited by the rate at which heat can be removed from the device footprint, which averages well above 100 W/cm[superscript 2] (locally this heat flux can exceed 1000 W/cm[superscript 2]). State-of-the-art air cooling strategies which utilize the sensible heat are insufficient at these large heat fluxes. As a result, novel thermal management solutions such as via thin-film evaporation that utilize the latent heat of vaporization of a fluid are needed. The high latent heat of vaporization associated with typical liquidvapor phase change phenomena allows significant heat transfer with small temperature rise. In this work, we demonstrate a promising thermal management approach where square arrays of cylindrical micropillar arrays are used for thin-film evaporation. The microstructures control the liquid film thickness and the associated thermal resistance in addition to maintaining a continuous liquid supply via the capillary pumping mechanism. When the capillary-induced liquid supply mechanism cannot deliver sufficient liquid for phase change heat transfer, the critical heat flux is reached and dryout occurs. This capillary limitation on thin-film evaporation was experimentally investigated by fabricating well-defined silicon micropillar arrays using standard contact photolithography and deep reactive ion etching. A thin film resistive heater and thermal sensors were integrated on the back side of the test sample using e-beam evaporation and acetone lift-off. The experiments were carried out in a controlled environmental chamber maintained at the water saturation pressure of ≈3.5 kPa and ≈25 °C. We demonstrated significantly higher heat dissipation capability in excess of 100 W/cm[superscript 2]. These preliminary results suggest the potential of thin-film evaporation from microstructured surfaces for advanced thermal management applications. |
| first_indexed | 2024-09-23T13:34:17Z |
| format | Article |
| id | mit-1721.1/120516 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T13:34:17Z |
| publishDate | 2019 |
| publisher | American Society of Mechanical Engineers |
| record_format | dspace |
| spelling | mit-1721.1/1205162022-10-01T15:46:32Z Capillary-Limited Evaporation From Well-Defined Microstructured Surfaces Adera, Solomon Raj, Rishi Wang, Evelyn Massachusetts Institute of Technology. Department of Mechanical Engineering Adera, Solomon Raj, Rishi Wang, Evelyn Thermal management is increasingly becoming a bottleneck for a variety of high power density applications such as integrated circuits, solar cells, microprocessors, and energy conversion devices. The performance and reliability of these devices are usually limited by the rate at which heat can be removed from the device footprint, which averages well above 100 W/cm[superscript 2] (locally this heat flux can exceed 1000 W/cm[superscript 2]). State-of-the-art air cooling strategies which utilize the sensible heat are insufficient at these large heat fluxes. As a result, novel thermal management solutions such as via thin-film evaporation that utilize the latent heat of vaporization of a fluid are needed. The high latent heat of vaporization associated with typical liquidvapor phase change phenomena allows significant heat transfer with small temperature rise. In this work, we demonstrate a promising thermal management approach where square arrays of cylindrical micropillar arrays are used for thin-film evaporation. The microstructures control the liquid film thickness and the associated thermal resistance in addition to maintaining a continuous liquid supply via the capillary pumping mechanism. When the capillary-induced liquid supply mechanism cannot deliver sufficient liquid for phase change heat transfer, the critical heat flux is reached and dryout occurs. This capillary limitation on thin-film evaporation was experimentally investigated by fabricating well-defined silicon micropillar arrays using standard contact photolithography and deep reactive ion etching. A thin film resistive heater and thermal sensors were integrated on the back side of the test sample using e-beam evaporation and acetone lift-off. The experiments were carried out in a controlled environmental chamber maintained at the water saturation pressure of ≈3.5 kPa and ≈25 °C. We demonstrated significantly higher heat dissipation capability in excess of 100 W/cm[superscript 2]. These preliminary results suggest the potential of thin-film evaporation from microstructured surfaces for advanced thermal management applications. United States. Office of Naval Research National Science Foundation (U.S.). Graduate Research Fellowship Program Battelle 2019-02-21T15:01:58Z 2019-02-21T15:01:58Z 2013-12 2019-01-09T18:05:21Z Article http://purl.org/eprint/type/JournalArticle 978-0-7918-5615-4 http://hdl.handle.net/1721.1/120516 Adera, Solomon, Rishi Raj, and Evelyn N. Wang. “Capillary-Limited Evaporation From Well-Defined Microstructured Surfaces.” ASME 2013 4th International Conference on Micro/Nanoscale Heat and Mass Transfer, 11-14 December, 2014, Hong Kong, China, ASME, 2014. © 2013 by ASME https://orcid.org/0000-0002-0258-0745 https://orcid.org/0000-0001-7045-1200 http://dx.doi.org/10.1115/MNHMT2013-22120 ASME 2013 4th International Conference on Micro/Nanoscale Heat and Mass Transfer Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Society of Mechanical Engineers ASME |
| spellingShingle | Adera, Solomon Raj, Rishi Wang, Evelyn Capillary-Limited Evaporation From Well-Defined Microstructured Surfaces |
| title | Capillary-Limited Evaporation From Well-Defined Microstructured Surfaces |
| title_full | Capillary-Limited Evaporation From Well-Defined Microstructured Surfaces |
| title_fullStr | Capillary-Limited Evaporation From Well-Defined Microstructured Surfaces |
| title_full_unstemmed | Capillary-Limited Evaporation From Well-Defined Microstructured Surfaces |
| title_short | Capillary-Limited Evaporation From Well-Defined Microstructured Surfaces |
| title_sort | capillary limited evaporation from well defined microstructured surfaces |
| url | http://hdl.handle.net/1721.1/120516 https://orcid.org/0000-0002-0258-0745 https://orcid.org/0000-0001-7045-1200 |
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