Jet blade ejector nozzle

Abstract

A jet engine assembly having a jet engine and an unsteady flow ejector. The unsteady flow ejector segregates the exhaust flow from the jet engine into a plurality of rotating high velocity, low density jets and a plurality of rotating low pressure voids. The low pressure voids are employed to entrain at least a portion of a secondary flow of air which is mixed with the jets to produce a mixed flow having a relatively higher flow rate and a relatively lower velocity than the exhaust flow. A method for attenuating the noise that is produced by the exhaust flow of a jet engine is also provided.

What is claimed is:  
     
         1 . A jet engine assembly comprising: 
 a turbofan jet engine, the turbofan jet engine having an engine core for powering a fan, the engine core producing an engine core flow and the fan producing a fan flow; and    an unsteady flow ejector having a multi-bladed rotor, the rotor being disposed within the engine core flow and rotating in response to a transfer of momentum therefrom;    wherein rotation of the rotor within the engine core flow generates a plurality of high velocity, low density rotating jets and a plurality of low pressure voids, each of the voids being spaced between two of the jets, each of the voids entraining a portion of the fan flow, the jets and the entrained portion of the fan flow mixing to produce a mixed flow having a relatively higher flow rate and a relatively lower velocity than the engine core flow.    
     
     
         2 . The jet engine assembly of  claim 1 , wherein the rotor includes a hub and a plurality of blades, each of the blades being fixed to the hub and having a face portion, an end portion and a relieved portion, each of the relieved portions having a cavity, each of the cavities emanating from a point on an outer surface of a respective one of the blades and tapering downwardly toward the hub and outwardly toward the end portion, wherein the cavity operates a flow channel for the fan flow to increase a rate with which the fan flow is entrained.  
     
     
         3 . The jet engine assembly of  claim 1 , further comprising a duct having a hollow cavity, the turbofan engine being coupled to the duct and at least partially disposed within the hollow cavity.  
     
     
         4 . The jet engine assembly of  claim 1 , wherein the turbofan engine and the unsteady flow ejector are disposed within the duct.  
     
     
         5 . A noise suppressor for attenuating noise associated with a high-velocity discharge flow, the noise suppressor comprising: 
 an unsteady flow elector having a multi-bladed rotor that is adapted to be disposed in the discharge flow and rotate in response to a transfer of energy therefrom, the rotor having a blade spacing that generates a plurality of high-velocity, low density rotating jets and a plurality of low pressure voids, each of the voids being spaced between an associated pair of the jets, the low pressure voids operably entraining a secondary flow of air.    
     
     
         6 . A jet engine assembly comprising: 
 an inlet for providing an inlet flow of air;    a turbojet engine having a turbine and a combuster, the turbojet engine receiving at least a portion of the inlet flow of air and generating a propulsive primary flow; and    an unsteady flow ejector having a multi-bladed rotor, the rotor being disposed within the primary flow and rotating in response to a transfer of momentum therefrom, the rotor employing the primary flow to generate a plurality of high velocity, low density rotating jets and a plurality of low pressure voids, each of the voids being spaced between an associated pair of the jets, the unsteady flow ejector being selectively operable for entraining a secondary flow of air into voids;    the jet engine assembly being operable in a first mode wherein the secondary flow is a flow of ambient air that is introduced directly into the unsteady flow ejector, each of the voids entraining a portion of the ambient flow, the jets and the entrained portion of the secondary flow mixing to attenuate a noise level of an exhaust flow of air exiting the turbojet engine.    
     
     
         7 . The jet engine assembly of  claim 6 , wherein the jet engine assembly is further operable in a second mode wherein the secondary flow includes a flow of bypass air, the bypass air being directed from the inlet around the combuster and into the unsteady flow ejector, each of the voids entraining a portion of the secondary flow, the jets and the entrained portion of the secondary flow mixing to augment a level of thrust produced by the turbojet engine.  
     
     
         8 . The jet engine assembly of  claim 7 , wherein the secondary flow also includes a boundary-layer bleed flow when the jet engine assembly is operating in the second mode.  
     
     
         9 . The jet engine assembly of  claim 7 , wherein the jet engine assembly is further operable in a third mode wherein the secondary flow includes a boundary-layer bleed flow, the boundary-layer bleed flow being directed from the turbojet engine into the unsteady flow ejector, each of the voids entraining a portion of the secondary flow, the jets and the entrained portion of the secondary flow mixing to augment a level of thrust produced by the turbojet engine.  
     
     
         10 . The jet engine assembly of  claim 9 , wherein the secondary flow also includes an engine cooling air flow when the jet engine assembly is operating in the third mode.  
     
     
         11 . The jet engine assembly of  claim 9 , further comprising a variable geometry nozzle.  
     
     
         12 . The jet engine assembly of  claim 6 , wherein the rotor is mounted for rotation on a turbine shaft that rotatably supports the turbine.  
     
     
         13 . The jet engine assembly of  claim 6 , wherein the rotor includes a hub and a plurality of blades, each of the blades being fixed to the hub and having a face portion, an end portion and a relieved portion, each of the relieved portions having a cavity, each of the cavities emanating from a point on an outer surface of a respective one of the blades and tapering downwardly toward the hub and outwardly toward the end portion, wherein the cavity operates a flow channel for the secondary flow to increase a rate with which the secondary flow is entrained.