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A RESEARCH AND DEVELOPMENT OF PBCF (PROPELLER BOSS CAP FINS), 2ND REPORT: STUDY ON PROPELLER SLIPSTREAM AND ACTUAL SHIP PERFORMANCE
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1989
Year
AeroacousticsEngineeringShip ManeuveringFluid MechanicsMarine EngineeringNaval ArchitectureMarine HydrodynamicsPbcf EffectShip ResistancePropulsionHub VortexBoss CapFluid MachineryStrength Of ShipOcean EngineeringAerospace EngineeringShip DesignSeakeeping And ControlAerodynamics
The concept of PBCFs (Propeller Boss Cap Fins) is that a number of small fins--as many as there are propeller blades--are attached to the boss cap (hub cone) and rotate together with the blades. The hub vortex is considerably weakened and the kinetic energy from the rotating flow around the boss cap is recovered by the fins, significantly increasing propeller efficiency. As a follow up to a previous paper on the PBCF effect, the authors describe further research to measure the flow behind the propeller using a 3D laser doppler velocimeter, carry out force measurements on PBCFs and perform cavitation tests in a propeller slipstream. They also relate how analyses of the data from eleven sea trials of various kinds of ships and of actual voyage data showed the PBCF effect to yield an average efficiency gain of about 4%.