SOME MOLECULAR EFFECTS IN DRAG REDUCTION: A SUMMARY†
Titel:
SOME MOLECULAR EFFECTS IN DRAG REDUCTION: A SUMMARY†
Auteur:
Ting, Robert Y.
Verschenen in:
Chemical engineering communications
Paginering:
Jaargang 15 (1982) nr. 5-6 pagina's 331-342
Jaar:
1982-05-01
Inhoud:
Dilute solutions of high molecular weight polymers have drawn a great deal of interest in recent years because of their drag reducing characteristics. It is well-known now that a substantial reduction in turbulent frictional drag can be achieved with a very small amount of polymeric additives, usually only a few parts per million by weight (ppmw) in concentration. This unique phenomenon has offered a new dimension in the design development of new marine systems for higher speed, longer range, larger payload as well as possibly quieter machinery. Although the discovery of this turbulent drag reduction phenomenon may be traced back to Toms1 and Mysels2 in the 1940's, the U.S. Navy's exploration of the turbulent drag reduction effect did not begin until the pioneering effort of Hoyt and Fabula in the 1960's. 3 During a period of several years in the early 19707apos;s, an interdisciplinary group at the Naval Research Laboratory undertook an intensive basic research effort to study the effects of polymer molecular structure on turbulent drag reduction. Model compounds were synthesized in the laboratory, and their drag reducing properties characterized. Polymers including polyacrylamide and its derivatives, polyacrylic acid, poiyphosphate and association colloids have been investigated. In this report, an attempt is made to highlight some of the results from that program in a brief summary form.
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