Sangam: A Confluence of Knowledge Streams

Hydrophobic coatings for film boiling based drag reduction on a torpedo model

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dc.contributor Jacopo Buongiorno and Thomas McKrell.
dc.contributor Massachusetts Institute of Technology. Department of Mechanical Engineering.
dc.contributor Massachusetts Institute of Technology. Department of Mechanical Engineering.
dc.creator Campbell, Ian J. (Ian James Kenneth)
dc.date 2015-12-03T20:53:41Z
dc.date 2015-12-03T20:53:41Z
dc.date 2015
dc.date 2015
dc.date.accessioned 2022-05-04T06:27:46Z
dc.date.available 2022-05-04T06:27:46Z
dc.identifier http://hdl.handle.net/1721.1/100104
dc.identifier 929460026
dc.identifier.uri http://localhost:8080/xmlui/handle/CUHPOERS/3024
dc.description Thesis: Nav. E., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.
dc.description Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.
dc.description Cataloged from PDF version of thesis.
dc.description Includes bibliographical references (pages 123-124).
dc.description Previous research has shown that porous, hydrophobic surfaces exhibit a dramatic reduction in critical heat flux (CHF), the amount of heat over a surface area required to initiate film boiling. Film boiling is characterized by the presence of a vapor layer which remains as long as the surface temperature stays above the Leidenfrost point. This vapor layer has poor heat transfer characteristics but has the potential to reduce drag by acting as a buffer between the solid surface and the liquid. The goals of this research were to quantify the drag reduction due to film boiling, examine the durability of the coating and explore the feasibility of this concept for application to a torpedo. A torpedo was chosen due to its high speed and reduced emphasis on durability, since it is only used operationally once. A hydrophobic coating was created in the laboratory using a layer-by-layer (LBL) process and its performance was compared to that of a commercial hydrophobic coating. Drop tests of uncoated and hydrophobic aluminum torpedo models were conducted in a custom-built apparatus housing a water column and a furnace, and recorded with a high-speed video camera in order to measure position versus time. Terminal velocity was extrapolated from the data and used to calculate drag coefficients. The data from this set of experiments showed that film boiling increased average terminal velocity by 23%, which corresponded to a 32% reduction in the drag coefficient.
dc.description by Ian J. Campbell.
dc.description Nav. E.
dc.description S.M.
dc.format 124 pages
dc.format application/pdf
dc.language eng
dc.publisher Massachusetts Institute of Technology
dc.rights M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.
dc.rights http://dspace.mit.edu/handle/1721.1/7582
dc.subject Mechanical Engineering.
dc.title Hydrophobic coatings for film boiling based drag reduction on a torpedo model
dc.type Thesis


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