Enabling Highly Effective Boiling from Superhydrophobic Surfaces
| Autor: | Suresh V. Garimella, Justin A. Weibel, Taylor P. Allred |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Materials science
Critical heat flux General Physics and Astronomy 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Leidenfrost effect 010305 fluids & plasmas Superheating Heat flux Boiling 0103 physical sciences Heat transfer Wetting Composite material 0210 nano-technology Nucleate boiling |
| Zdroj: | Physical review letters. 120(17) |
| ISSN: | 1079-7114 |
| Popis: | A variety of industrial applications such as power generation, water distillation, and high-density cooling rely on heat transfer processes involving boiling. Enhancements to the boiling process can improve the energy efficiency and performance across multiple industries. Highly wetting textured surfaces have shown promise in boiling applications since capillary wicking increases the maximum heat flux that can be dissipated. Conversely, highly nonwetting textured (superhydrophobic) surfaces have been largely dismissed for these applications as they have been shown to promote formation of an insulating vapor film that greatly diminishes heat transfer efficiency. The current Letter shows that boiling from a superhydrophobic surface in an initial Wenzel state, in which the surface texture is infiltrated with liquid, results in remarkably low surface superheat with nucleate boiling sustained up to a critical heat flux typical of hydrophilic wetting surfaces, and thus upends this conventional wisdom. Two distinct boiling behaviors are demonstrated on both micro- and nanostructured superhydrophobic surfaces based on the initial wetting state. For an initial surface condition in which vapor occupies the interstices of the surface texture (Cassie-Baxter state), premature film boiling occurs, as has been commonly observed in the literature. However, if the surface texture is infiltrated with liquid (Wenzel state) prior to boiling, drastically improved thermal performance is observed; in this wetting state, the three-phase contact line is pinned during vapor bubble growth, which prevents the development of a vapor film over the surface and maintains efficient nucleate boiling behavior. |
| Databáze: | OpenAIRE |
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