The design and construction of a novel pipe flow apparatus for exploring polymer drag reduction

Turbulent flows are inherently less efficient than their laminar counterparts, and this additional dissipation results in the waste of a substantial amount of energy in any turbulent fluid system. It has long been known that the addition of a small amount of high molecular weight polymer to a turbulent flow can greatly increase flow efficiency - improvements of 70 % or more are not uncommon. While the mechanism behind this so-called polymer drag reduction - also known as the Toms Effect - is not yet well understood, it has been asserted that the redistribution of energy in the turbulent flow structure via molecular stretching and transport is essential to the increased flow efficiency. This implies that the relevant dimensionless parameter is the ratio of the polymer time scale - the relaxation time - to the relevant flow time scale - the diffusion time. This ratio is known as the Weissenberg Number, and the role it plays in polymer drag reduction has not been explored experimentally in a systematic way. It has been known for some time that the slimes produced by fishes are effective drag reducing agents per unit weight; the slime of the Pacific Hagfish (Eptatretus stout), in particular, contains both long, flexible fibers and high molecular weight mucin polymer chains.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2005

Author dc:creator

• MacMinn, Christopher William

Advisor dc:contributor.advisor

• Gareth H. McKinley.

• Mechanical Engineering.

Statement 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.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/32953

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/32953