Passive thrust enhancement using circulation control

Abstract

A passive thrust enhancement system having a propeller, which includes a propeller hub, a first propeller blade, a second propeller blade, wherein each of the first and second propeller blades include a fluid flow channel within the first and second propeller blades, which is fluidly connected to a flow exit slot, and a flow capture device, which includes a plenum chamber, mounted on the propeller hub, wherein the plenum chamber is fluidly connected to the fluid flow channels.

What is claimed is: 
     
         1 . A passive thrust enhancement system comprising:
 a propeller, which includes:
 a propeller hub; 
 a first propeller blade; 
 a second propeller blade; 
 wherein each of said first and said second propeller blades include a fluid flow channel within said first and said second propeller blades, which is fluidly connected to a flow exit slot; and 
   a flow capture device, which includes a plenum chamber, mounted on said propeller hub, wherein said plenum chamber is fluidly connected to said fluid flow channels.   
     
     
         2 . The passive thrust enhancement system of  claim 1 , wherein said flow capture device is a conical shape with straight sides. 
     
     
         3 . The passive thrust enhancement system of  claim 1 , wherein said flow capture device is a conical shape with continuously curved sides. 
     
     
         4 . The passive thrust enhancement system of  claim 1 , wherein the diameter of said flow capture device is less than or equal to 150% of the diameter of said propeller hub. 
     
     
         5 . The passive thrust enhancement system of  claim 1 , wherein the distance that said flow capture device extends from said propeller is between ¼ and 1 diameters of said propeller hub. 
     
     
         6 . The passive thrust enhancement system of  claim 1 , further comprising a flow control valve. 
     
     
         7 . The passive thrust enhancement system of  claim 1 , wherein said propeller is an aircraft propeller. 
     
     
         8 . The passive thrust enhancement system of  claim 1 , wherein said propeller is a boat propeller. 
     
     
         9 . The passive thrust enhancement system of  claim 1 , wherein said propeller is a horizontal axis wind turbine. 
     
     
         10 . A passive thrust enhancement system comprising:
 a propeller, which includes:
 a propeller hub; 
 a first propeller blade; 
 a second propeller blade; 
 wherein each of said first and said second propeller blades include a fluid flow channel within said first and said second propeller blades, which is fluidly connected to a flow exit slot; 
   a flow capture device, which includes a plenum chamber, mounted on said propeller hub, wherein said plenum chamber is fluidly connected to said fluid flow channels; and   a flow control valve.   
     
     
         11 . The passive thrust enhancement system of  claim 10 , wherein said flow capture device is a conical shape with straight sides. 
     
     
         12 . The passive thrust enhancement system of  claim 10 , wherein said flow capture device is a conical shape with continuously curved sides. 
     
     
         13 . The passive thrust enhancement system of  claim 10 , wherein the diameter of said flow capture device is less than or equal to 150% of the diameter of said propeller hub. 
     
     
         14 . The passive thrust enhancement system of  claim 10 , wherein the distance that said flow capture device extends from said propeller is between ¼ and 1 diameters of said propeller hub. 
     
     
         15 . The passive thrust enhancement system of  claim 10 , wherein said propeller is an aircraft propeller. 
     
     
         16 . The passive thrust enhancement system of  claim 10 , wherein said propeller is a boat propeller. 
     
     
         17 . The passive thrust enhancement system of  claim 10 , wherein said propeller is a horizontal axis wind turbine.