Microfluidic transport is finding increasing application in a number of emerging technologies. At these scales, classical analysis shows that the required fluid driving pressure is inversely proportional to the hydraulic diameter to the fourth power. Consequently, generating fluid motion at these physical scales is a challenge. There is thus considerable incentive for developing strategies to reduce the frictional resistance to fluid flow. A novel approach recently proposed is fabrication of micro-ribs and cavities in the channel walls which are treated with a hydrophobic coating. This reduces the surface contact area between the flowing liquid and the solid wall, yielding walls with no-slip and shear-free regions at the microscale. The shear-free regions consist of a liquid-vapor meniscus above the cavities between micro-ribs. Reductions in the flow resistance are thus possible. This paper reports results of an analytical and experimental investigation of the laminar, fully-developed flow in a parallel plate microchannel whose walls are microengineered in this fashion. The micro-ribs and cavities are oriented parallel to the flow direction. The channel walls are modeled in an idealized fashion, with the shape of liquid-vapor meniscus approximated as flat and characterized by vanishing shear stress. Predictions are presented for the friction factor-Reynolds number product as a function of relevant governing dimensionless parameters. Comparisons are made between the smooth-wall classical channel flow results and predictions for the microengineered channel walls. Results show that significant reductions in the frictional pressure drop are possible. Reductions in frictional resistance increase as the channel hydraulic diameter and/or micro-rib width are reduced. The frictional pressure drop predictions are in good agreement with experimental measurements made at dynamically similar conditions, with greater deviation observed with increasing relative size of the shear-free regions.
Skip Nav Destination
ASME 2005 Summer Heat Transfer Conference collocated with the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems
July 17–22, 2005
San Francisco, California, USA
Conference Sponsors:
- Heat Transfer Division and Electronic and Photonic Packaging Division
ISBN:
0-7918-4731-4
PROCEEDINGS PAPER
Laminar Fully-Developed Flow in a Microchannel With Patterned Ultrahydrophobic Walls
B. Woolford,
B. Woolford
Brigham Young University, Provo, UT
Search for other works by this author on:
B. W. Webb
B. W. Webb
Brigham Young University, Provo, UT
Search for other works by this author on:
B. Woolford
Brigham Young University, Provo, UT
K. Jeffs
Brigham Young University, Provo, UT
D. Maynes
Brigham Young University, Provo, UT
B. W. Webb
Brigham Young University, Provo, UT
Paper No:
HT2005-72726, pp. 481-488; 8 pages
Published Online:
March 9, 2009
Citation
Woolford, B, Jeffs, K, Maynes, D, & Webb, BW. "Laminar Fully-Developed Flow in a Microchannel With Patterned Ultrahydrophobic Walls." Proceedings of the ASME 2005 Summer Heat Transfer Conference collocated with the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems. Heat Transfer: Volume 1. San Francisco, California, USA. July 17–22, 2005. pp. 481-488. ASME. https://doi.org/10.1115/HT2005-72726
Download citation file:
17
Views
Related Proceedings Papers
Related Articles
A Unified Approach for Flow Analysis of Magnetorheological Fluids
J. Appl. Mech (July,2011)
Related Chapters
Surface Analysis and Tools
Tribology of Mechanical Systems: A Guide to Present and Future Technologies
Extended-Surface Metallurgy
Heat Exchanger Engineering Techniques
Dynamic Behavior of Pumping Systems
Pipeline Pumping and Compression Systems: A Practical Approach