TY - GEN
T1 - Role of copper oxide layer on pool boiling performance with femtosecond laser processed surfaces
AU - Kruse, Corey
AU - Peng, Edwin
AU - Zuhlke, Craig
AU - Shield, Jeff
AU - Alexander, Dennis
AU - Ndao, Sidy
AU - Gogos, George
N1 - Funding Information:
This work has been supported by a grant through the Nebraska Center for Energy Sciences Research (NCESR) Grant # 803, A-00-A-03, a NASA EPSCoR Grant # 2014-198-SC1, a NASA Space Technology Research Fellowship (NSTRF) Grant # NNX14AM50H, and an Office of Naval Research (ONR) Grant # FA4600-12-D-9000-0045.
Publisher Copyright:
© 2017 ASME The American Society of Mechanical Engineers.
PY - 2017
Y1 - 2017
N2 - Copper pool boiling surfaces are tested for pool boiling enhancement due to femtosecond laser surface processing (FLSP). FLSP creates self-organized micro/nanostructures on metallic surfaces and creates highly wetting and wicking surfaces with permanent surface features. In this study two series of samples were created. The first series consists of three flat FLSP copper surfaces with varying microstructures and the second series is an open microchannel configuration with laser processing over the horizontal surfaces of the microchannels. These microchannels range in height from 125 microns to 380 microns. Each of these surfaces were tested for pool boiling performance. It was found that all the processed surfaces except one resulted in a decrease in critical heat flux and heat transfer coefficient compared to an unprocessed surface. It was found that the laser fluence parameter had a significant role in whether there was an increase in CHF or HTC. A cross sectioning technique was employed to study the different layers of the microstructure and to understand how FLSP could have a negative effect on the CHF and HTC. It was found that a thick oxide layer forms during the FLSP process of copper in an open-air atmosphere. The thickness and uniformity of the oxide layer is highly dependent on the laser fluence. A low fluence sample results in an inconsistent oxide layer of nonuniform thickness and subsequently an increase in CHF and HTC. A high laser fluence sample results in a uniformly thick oxide layer which increases the thermal resistance of the sample and allows for a premature CHF and decrease in HTC.
AB - Copper pool boiling surfaces are tested for pool boiling enhancement due to femtosecond laser surface processing (FLSP). FLSP creates self-organized micro/nanostructures on metallic surfaces and creates highly wetting and wicking surfaces with permanent surface features. In this study two series of samples were created. The first series consists of three flat FLSP copper surfaces with varying microstructures and the second series is an open microchannel configuration with laser processing over the horizontal surfaces of the microchannels. These microchannels range in height from 125 microns to 380 microns. Each of these surfaces were tested for pool boiling performance. It was found that all the processed surfaces except one resulted in a decrease in critical heat flux and heat transfer coefficient compared to an unprocessed surface. It was found that the laser fluence parameter had a significant role in whether there was an increase in CHF or HTC. A cross sectioning technique was employed to study the different layers of the microstructure and to understand how FLSP could have a negative effect on the CHF and HTC. It was found that a thick oxide layer forms during the FLSP process of copper in an open-air atmosphere. The thickness and uniformity of the oxide layer is highly dependent on the laser fluence. A low fluence sample results in an inconsistent oxide layer of nonuniform thickness and subsequently an increase in CHF and HTC. A high laser fluence sample results in a uniformly thick oxide layer which increases the thermal resistance of the sample and allows for a premature CHF and decrease in HTC.
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U2 - 10.1115/icnmm2017-5574
DO - 10.1115/icnmm2017-5574
M3 - Conference contribution
AN - SCOPUS:85088067036
T3 - ASME 2017 15th International Conference on Nanochannels, Microchannels, and Minichannels, ICNMM 2017
BT - ASME 2017 15th International Conference on Nanochannels, Microchannels, and Minichannels, ICNMM 2017
PB - American Society of Mechanical Engineers
T2 - ASME 2017 15th International Conference on Nanochannels, Microchannels, and Minichannels, ICNMM 2017
Y2 - 27 August 2017 through 30 August 2017
ER -