Influence of Copper Oxide on Femtosecond Laser Surface Processed Copper Pool Boiling Heat Transfer Surfaces
Autor: | Dennis R. Alexander, Corey Kruse, Edwin Peng, George Gogos, Alfred Tsubaki, Craig Zuhlke, Jeffrey E. Shield, Sidy Ndao, Mark R. Anderson |
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Rok vydání: | 2019 |
Předmět: |
010302 applied physics
Copper oxide Materials science Critical heat flux Mechanical Engineering Polishing chemistry.chemical_element 02 engineering and technology Heat transfer coefficient 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Copper chemistry.chemical_compound Thermal conductivity chemistry Chemical engineering Mechanics of Materials 0103 physical sciences Heat transfer Femtosecond General Materials Science 0210 nano-technology |
Zdroj: | Journal of Heat Transfer. 141 |
ISSN: | 1528-8943 0022-1481 |
DOI: | 10.1115/1.4043129 |
Popis: | Pool boiling heat transfer with the use of femtosecond laser surface processing (FLSP) on copper surfaces has been studied. FLSP creates a self-organized micro/nanostructured surface. In the previous pool boiling heat transfer studies with stainless steel FLSP surfaces, enhancements in critical heat flux (CHF) and heat transfer coefficients (HTCs) were observed compared to the polished reference surface. However, this study shows that copper FLSP surfaces exhibit reductions in both CHF and HTCs consistently. This reduction in heat transfer performance is a result of an oxide layer that covers the surface of the microstructures and acts as an insulator due to its low thermal conductivity. The oxide layer was observed and measured with the use of a focused ion beam milling process and found to have thickness of a few microns. The thickness of this oxide layer was found to be related to the laser fluence parameter. As the fluence increased, the oxide layer thickness increased and the heat transfer performance decreased. For a specific test surface, the oxide layer was selectively removed by a chemical etching process. The removal of the oxide layer resulted in an enhancement in the HTC compared to the polished reference surface. Although the original FLSP copper surfaces were unable to outperform the polished reference curve, this experiment illustrates how an oxide layer can significantly affect heat transfer results and dominate other surface characteristics (such as increased surface area and wicking) that typically lead to heat transfer enhancement. |
Databáze: | OpenAIRE |
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