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Capillarity Effect on Two-phase Flow Resistance in Microchannels

Rapolu, Prakash
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1204082574

Abstract Details

2008, MS, University of Cincinnati, Engineering : Mechanical Engineering.
Two-phase flow plays a major role in number of technologies used in fuel cells, bioreactors, phase and particle separators, thermal management systems, chemical reactors, etc. Some of these applications involve air–water two-phase flow in channels much less than 1 mm in diameter. The fundamental understanding of flow characteristics, such as flow regime, pressure drop, and heat transfer, is essential in the design and control of these devices. In this work, an experimental set-up is developed to investigate the effects of surface energy/surface wettability and geometry on characteristics of two-phase flow in horizontal microchannels at adiabatic conditions. Two-phase (air-water) slug flow is established in microchannel test sections of varying sol-gel dip coated surface wettabilities. Pressure drop measurements and flow pattern detection by high speed visualization are employed to characterize the flow. Results indicate that two-phase flow resistance is a strong function of surface wettability and it increases with static contact angle. Significant change in contact line in advancing and receding interface, and thus increase in flow resistance, is observed with increase of hydrophobicity while geometry of the channels influences the frequency of the slugs. Presence of thin liquid film, whose thickness is a strong function of wettability, is observed experimentally which clearly elucidates the pressure drop variation with surface wettability. Hence for characterizing two-phase flow in microchannels surface wettability parameters should be accounted appropriately.
Dr. Sang Young Son (Advisor)
76 p.
Engineering, Mechanical
Surface tension; Surface wettability; Microchannels; Two-phase flow; Two-phase flow resistance (Pressure Drop); Dynamic Contact Angle; Slug Flow

Recommended Citations

Citations

  • Rapolu, P. (2008). Capillarity Effect on Two-phase Flow Resistance in Microchannels [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1204082574

    APA Style (7th edition)

  • Rapolu, Prakash. Capillarity Effect on Two-phase Flow Resistance in Microchannels. 2008. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1204082574.

    MLA Style (8th edition)

  • Rapolu, Prakash. "Capillarity Effect on Two-phase Flow Resistance in Microchannels." Master's thesis, University of Cincinnati, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1204082574

    Chicago Manual of Style (17th edition)

ucin1204082574
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© 2007, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.