Propeller, propeller propulsion system and vessel comprising propulsion system

Abstract

The invention refers to a propeller comprising a base ( 2, 15 ) and a plurality of blades ( 1, 14 ) extending from said base in an upstream tilted manner, i.e. in the direction corresponding to the forward motion direction (D 1 ) of the craft. The blades extend in a direction forming an acute angle α with the forward motion direction, 10°≦α≦80°. The invention also refers to a propulsion system including the propeller, as well as to a craft including the propulsion system.

1 . A propeller having a geometric pitch and 
 the propeller being configured so as to rotate about an axis of rotation when the propeller is driven by a drive shaft of a craft for the purpose of propelling the craft in a first direction parallel to the axis of rotation and corresponding to the forward motion direction of the craft, and propelling a fluid in a second general direction opposite to the first direction;    the propeller comprising:    a base;    a plurality of blades, 
 each blade having a surface defined by a first end joined to the base and a second free end separating a leading edge of the blade from a trailing edge of the blade;  
 the blade being oriented to have an angle of attack;  
 the blade having a convex surface suction side extending in a third direction from the first end towards the blade tip, the third direction being a direction in which one section of the blade extending in a plane including the axis of rotation and the blade tip;  
 the blade having the leading edge upstream from the trailing edge, the leading edge and the trailing edge substantially extending in the direction from the first end to the blade tip;  
   the blade tip being an end point separating the leading edge from the trailing edge;    the third direction forming an acute angle α with the first direction 10°≦α≦80°, in a plane including the axis of rotation;    each blade having a length equal to a length of one blade perpendicular to the axis of rotation divided by sin α and    having a surface equal to a surface of one blade perpendicular to the axis of rotation divided by sin α   for increasing thrust provided by the blade.    
   
   
       2 . A propeller according to  claim 1 , wherein 20°≦α≦70°.  
   
   
       3 . A propeller according to  claim 1 , wherein 30°≦α≦60°.  
   
   
       4 . A propeller according to  claim 1 , wherein 40°≦α≦50°.  
   
   
       5 . A propeller according to  claim 1 , wherein α=45°.  
   
   
       6 . A propeller according to  claim 1 , wherein the propeller has two blades.  
   
   
       7 . A propeller according to  claim 1 , wherein the propeller comprises at least three blades.  
   
   
       8 . A propeller according to  claim 1 , wherein the blades have an elongated configuration in the direction from the first end to the second end.  
   
   
       9 . A propulsion system, comprising at least one propeller according to  claim 1 , and a drive shaft joined to the propeller such that the drive shaft is operable to turn the propeller about the axis of rotation.  
   
   
       10 . A propulsion system according to  claim 9 , further comprising a nozzle concentrically located around the axis of rotation of the propeller and laterally enveloping the propeller, the nozzle having a fluid entry front end and a fluid exit rear end.  
   
   
       11 . A propulsion system according to  claim 9 , wherein each blade is joined to the drive shaft or to an element configured as an axial extension of the drive shaft by at least one retention brace on the suction side to withstand centrifugal force.  
   
   
       12 . A propulsion system according to  claim 11 , wherein each blade is joined to the drive shaft or to an element configured as an axial extension of the drive shaft by at least two of the retention braces.  
   
   
       13 . A propulsion system according to  claim 11 , wherein each retention brace is arranged perpendicularly to the axis of rotation of the propeller.  
   
   
       14 . A propulsion system according to  claim 11 , wherein each retention brace has a symmetrical profile and a shape of a blade in feather position for craft cruising speed.  
   
   
       15 . A propulsion system according to  claim 11 , forming part of a turbojet fan, each blade being joined to a propeller base forming part of the drive shaft comprised of a rotor of the turbojet, each blade being joined to the rotor also by at least two of the retention braces.  
   
   
       16 . A propulsion system according to  claim 15 , further comprising a fairing tube radially surrounding the propeller.  
   
   
       17 . A craft, including a propulsion system according to  claim 9 .  
   
   
       18 . A craft according to  claim 17 , wherein the craft is an aquatic craft.  
   
   
       19 . A craft according to  claim 17 , wherein the craft is a submarine craft.  
   
   
       20 . A craft according to  claim 17 , wherein the craft is an aircraft.