TY - JOUR
T1 - Endoscopic Visualization of Contact Line Dynamics during Pool Boiling on Capillary-Activated Copper Microchannels
AU - Li, Jiaqi
AU - Zhu, Gaohua
AU - Kang, Daniel
AU - Fu, Wuchen
AU - Zhao, Yongyi
AU - Miljkovic, Nenad
N1 - Funding Information:
J.L. and G.Z. contributed equally to this work. The authors gratefully acknowledge funding support from the Toyota Motor Company. N.M. and J.L. gratefully acknowledge funding from the National Science Foundation under Award No. 1554249. N.M. gratefully acknowledges funding support from the International Institute for Carbon Neutral Energy Research (WPI‐I2CNER), sponsored by the Japanese Ministry of Education, Culture, Sports, Science, and Technology.
PY - 2020
Y1 - 2020
N2 - Microchannel surfaces are common to microfluidics, biofluidics, thermal management, and energy applications. Due to processing limitations for the majority of metallic materials, the majority of hyperfine microchannels used in microfluidics and thermo-fluids are fabricated on non-metallic substrates, for example, silicon and polydimethylsiloxane. Here, a technique to fabricate ultrasmall microchannels on arbitrary metallic materials is developed using photolithography in combination with electrochemical deposition. The technique is used to prepare copper microchannels and to investigate the pool boiling heat transfer performance with a focus on the three-phase contact line dynamics. The hydrodynamics of nucleating bubbles during boiling are observed in situ using in-liquid endoscopy. The results show that the variation of critical heat flux enhancement has a linear relationship with the contact line increase ratio. The scalable microchannel surfaces exhibit superior heat transfer performance with a maximum heat transfer coefficient) enhancement of 930% with ultra-low wall superheat of 5 °C. This work not only develops a scalable manufacturing method to develop ultra-small microchannels on metallic materials, it outlines design guidelines for structure optimization of pool boiling heat transfer for temperature sensitive applications, such as electronics thermal management.
AB - Microchannel surfaces are common to microfluidics, biofluidics, thermal management, and energy applications. Due to processing limitations for the majority of metallic materials, the majority of hyperfine microchannels used in microfluidics and thermo-fluids are fabricated on non-metallic substrates, for example, silicon and polydimethylsiloxane. Here, a technique to fabricate ultrasmall microchannels on arbitrary metallic materials is developed using photolithography in combination with electrochemical deposition. The technique is used to prepare copper microchannels and to investigate the pool boiling heat transfer performance with a focus on the three-phase contact line dynamics. The hydrodynamics of nucleating bubbles during boiling are observed in situ using in-liquid endoscopy. The results show that the variation of critical heat flux enhancement has a linear relationship with the contact line increase ratio. The scalable microchannel surfaces exhibit superior heat transfer performance with a maximum heat transfer coefficient) enhancement of 930% with ultra-low wall superheat of 5 °C. This work not only develops a scalable manufacturing method to develop ultra-small microchannels on metallic materials, it outlines design guidelines for structure optimization of pool boiling heat transfer for temperature sensitive applications, such as electronics thermal management.
KW - boiling heat transfer
KW - critical heat flux
KW - electrochemical deposition
KW - microchannel
KW - three-phase contact line
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U2 - 10.1002/adfm.202006249
DO - 10.1002/adfm.202006249
M3 - Article
AN - SCOPUS:85097031978
JO - Advanced Functional Materials
JF - Advanced Functional Materials
SN - 1616-301X
ER -