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Title: Capillary Rise of Nanostructured Microwicks

Capillarity refers to the driving force to propel liquid through small gaps in the absence of external forces, and hence enhanced capillary force has been pursued for various applications. In this study, flower like ZnO nanostructures are successfully deposited to enhance capillarity of microwick structures that are specially designed to augment boiling heat transfer performance. Microreactor-assisted nanomaterial deposition, MAND TM, is employed with a flow cell to deposit the ZnO nanostructures on a large sized microwick (4.3 cm × 10.7 cm) with dual-channel configuration. A capillary rise experiment based on the mass gain method is first performed using water and ethanol (EtOH) as the working liquids to demonstrate the enhanced capillary force induced by the ZnO nanostructure on the microwick structure. It is found that the coating of ZnO nanostructure effectively propels the working fluids through the nano- or micro pores created from the ZnO nanostructure and consequently improves the capillary force. In order to investigate the wicking mechanism of the ZnO coated microwick structure, the capillary rise result based on height measurement was compared with analytical models. It is found that the gravity effect and viscous force play an important role in wicking rise of the coated wick structure.more » This study aims at demonstrating the capability of the integrated MAND process with a flow cell for producing a large scaled nanostructured surface, which eventually has a great potential for enhanced boiling heat transfer.« less
Authors:
 [1] ; ORCiD logo [2] ;  [3] ;  [4]
  1. Oregon State Univ., Corvallis, OR (United States). School of Chemical, Biological, and Environmental Engineering; Pohang Univ. of Science and Technology (POSTECH) (Korea, Republic of). Dept. of Chemical Engineering
  2. Pacific Northwest National Lab. (PNNL), Corvallis, OR (United States). MicroProducts Breakthrough Inst.; Indian Inst. of Technology Bombay (IITB), Mumbai (India). Dept. of Mechanical Engineering
  3. Pacific Northwest National Lab. (PNNL), Corvallis, OR (United States). MicroProducts Breakthrough Inst.
  4. Oregon State Univ., Corvallis, OR (United States). School of Chemical, Biological, and Environmental Engineering
Publication Date:
Report Number(s):
PNNL-SA-136375
Journal ID: ISSN 2072-666X; PII: mi9040153
Grant/Contract Number:
AC05-76RL01830; CBET-1449383
Type:
Accepted Manuscript
Journal Name:
Micromachines
Additional Journal Information:
Journal Volume: 9; Journal Issue: 4; Journal ID: ISSN 2072-666X
Publisher:
MDPI
Research Org:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Oregon State Univ., Corvallis, OR (United States)
Sponsoring Org:
USDOE; National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; ZnO nanostructure; capillary wicking; ZnO nanoparticle assembly
OSTI Identifier:
1461810

Choi, Chang -Ho, Krishnan, Shankar, TeGrotenhuis, Ward, and Chang, Chih -Hung. Capillary Rise of Nanostructured Microwicks. United States: N. p., Web. doi:10.3390/MI9040153.
Choi, Chang -Ho, Krishnan, Shankar, TeGrotenhuis, Ward, & Chang, Chih -Hung. Capillary Rise of Nanostructured Microwicks. United States. doi:10.3390/MI9040153.
Choi, Chang -Ho, Krishnan, Shankar, TeGrotenhuis, Ward, and Chang, Chih -Hung. 2018. "Capillary Rise of Nanostructured Microwicks". United States. doi:10.3390/MI9040153. https://www.osti.gov/servlets/purl/1461810.
@article{osti_1461810,
title = {Capillary Rise of Nanostructured Microwicks},
author = {Choi, Chang -Ho and Krishnan, Shankar and TeGrotenhuis, Ward and Chang, Chih -Hung},
abstractNote = {Capillarity refers to the driving force to propel liquid through small gaps in the absence of external forces, and hence enhanced capillary force has been pursued for various applications. In this study, flower like ZnO nanostructures are successfully deposited to enhance capillarity of microwick structures that are specially designed to augment boiling heat transfer performance. Microreactor-assisted nanomaterial deposition, MANDTM, is employed with a flow cell to deposit the ZnO nanostructures on a large sized microwick (4.3 cm × 10.7 cm) with dual-channel configuration. A capillary rise experiment based on the mass gain method is first performed using water and ethanol (EtOH) as the working liquids to demonstrate the enhanced capillary force induced by the ZnO nanostructure on the microwick structure. It is found that the coating of ZnO nanostructure effectively propels the working fluids through the nano- or micro pores created from the ZnO nanostructure and consequently improves the capillary force. In order to investigate the wicking mechanism of the ZnO coated microwick structure, the capillary rise result based on height measurement was compared with analytical models. It is found that the gravity effect and viscous force play an important role in wicking rise of the coated wick structure. This study aims at demonstrating the capability of the integrated MAND process with a flow cell for producing a large scaled nanostructured surface, which eventually has a great potential for enhanced boiling heat transfer.},
doi = {10.3390/MI9040153},
journal = {Micromachines},
number = 4,
volume = 9,
place = {United States},
year = {2018},
month = {3}
}