Drag reduction properties of superhydrophobic mesh pipes

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Geraldi, N.R., Dodd, L.E., Xu, B.B., Wells, G.G., Wood, D., Newton, M.I. ORCID: 0000-0003-4231-1002 and McHale, G., 2017. Drag reduction properties of superhydrophobic mesh pipes. Surface Topography: Metrology and Properties, 5 (3), 034001. ISSN 2051-672X

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Official URL: http://doi.org/10.1088/2051-672X/aa793b

Abstract

Even with the recent extensive study into superhydrophobic surfaces, the fabrication of such surfaces on the inside walls of a pipe remains challenging. In this work we report a convenient bi-layered pipe design using a thin superhydrophobic metallic mesh formed into a tube, supported inside another pipe. A flow system was constructed to test the fabricated bi-layer pipeline, which allowed for
different constant flow rates of water to be passed through the pipe, whilst the differential pressure was measured, from which the drag coefficient (ƒ)and Reynolds numbers
(Re) were calculated. Expected values of ƒ were found for smooth glass pipes for the Reynolds number (Re) range 750 to 14000, covering the laminar and part of the turbulent regimes. Flow through plain meshes without the superhydrophobic coating were also measured over this range. After applying the superhydrophobic coating, ƒ was found to be less than that of an uncoated mesh, but greater than that of a smooth glass pipe of the same diameter. This demonstrates that a superhydrophobic mesh can support a plastron and provide a drag reduction compared to a plain mesh, however, the plastron is progressively destroyed with use and in particular at higher flow rates.

Item Type:

Journal article

Publication Title:

Surface Topography: Metrology and Properties

Creators:

Geraldi, N.R., Dodd, L.E., Xu, B.B., Wells, G.G., Wood, D., Newton, M.I. and McHale, G.

Publisher:

Institute of Physics Publishing

Date:

4 July 2017

Volume:

Number: