ENERGY EFFICIENT ASYMMETRIC PRE-SWIRL VANE AND TWISTED PROPELLER PROPULSION SYSTEM

摘要

ABSTRACTAn asymmetric set of pre-swirl vanes (stators) and aspecially matched propeller for use on an inclined shaft. Thepropulsor is designed by considering the mutual interaction of thepropeller on the vanes and the vanes on the propeller. Thepropulsor unit provides the following:1. increased propulsive efficiency due to the reduced rotational(swirl) and axial kinetic energy losses in the propulsor'sslipstream;2. reduction or elimination of propeller cavitation;3. reduction or elimination of unsteady propulsor forces as wellas propulsor-induced hull vibrations.A unique feature of the present invention is that a prior artflat faced commercially available propeller can be modified tomatch the vane flow field for optimum propulsor performance. Theuse of commercially available propellers reduces the installationor hardware cost significantly and allows the propeller to berepaired easily if damaged.Another unique feature is that the vanes operate well with anunmodified commercially available prior art flat faced, optimumconstant pitch propeller, and that the propeller as modified foruse with the vanes also performs exceptionally well without thevanes. The modified propeller without vanes in fact outperformedthe prior art flat faced optimum constant pitch propeller used onthe 41 foot test craft.