Accession Number : ADD006032

Title :   Apparatus for Improving the Overall Efficiency of a Marine Screw Propeller.

Descriptive Note : Patent Application,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Kehman,August F

Report Date : 16 Mar 1979

Pagination or Media Count : 11

Abstract : Elongate slots are formed near the leading edges of propeller blades and a supply of polyethylene oxide is ejected through the slots to form a continuous sheet of the polymer flowing on the suction side surface in the region where about 70% of the thrust loading is distributed. The polymer changes the propeller's pressure distribution and increases its lift factor and efficiency. When ejected at a proper flow rate, frictional drag also is reduced. The slots are shaped channels having a particular depth, width and directional orientation that assures the continuity of the flowing sheet. To achieve the benefits, polymer concentration is maintained at a level capable of providing a trailing edge concentration of about 2-20 ppm. (Author)

Descriptors :   *Patent applications, *Propellers(Marine), *Propeller blades, *Fluid flow, *Polymers, Leading edges, Slots, Polyethylene, Ethylene oxide, Ejection, Loads(Forces), Thrust control, Pressure distribution, Lift to drag ratio

Subject Categories : Plastics
      Marine Engineering
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE