Airfoil for a rotary machine including a propellor assembly
In some embodiments, an airfoil comprises a proximal end; a distal end opposite said proximal end; a distal portion extending adjacent said distal end; an edge extending between said proximal end and said distal end; and a surface extending between said proximal end and said distal end, said edge and said surface defining a sweep and a cahedral through said distal portion, wherein the distal portion extends over an acoustically active portion of the airfoil.
1. An airfoil, comprising:
a proximal end;
a distal end opposite said proximal end;
a distal portion extending adjacent said distal end;
an edge extending between said proximal end and said distal end; and
a surface extending between said proximal end and said distal end, said edge and said surface defining a sweep and a cahedral through said distal portion, wherein the distal portion extends over an acoustically active portion of the airfoil; and
wherein the acoustically active portion is defined by a region of the airfoil extending from the distal end to a location along the airfoil that generates 10 to 20 dB less noise than a location along the airfoil which generates a maximum level of noise.
2. The airfoil in accordance with claim 1 , wherein the acoustically active portion of the airfoil is determined by multiplying an acoustic source strength distributed radially along the airfoil by a radiation efficiency along the airfoil.
3. The airfoil in accordance with claim 1 , wherein said edge is at least one of a trailing edge and a leading edge.
4. The airfoil in accordance with claim 3 , wherein a camber of said airfoil is adjusted in span and chord directions of said airfoil to reduce adverse effects of a high flow acceleration around said at least one of a trailing edge and a leading edge.
5. The airfoil in accordance with claim 3 , wherein a twist of said airfoil is adjusted along a span of said airfoil to compensate for the aerodynamic loading due to the cahedral and the sweep.
6. The airfoil in accordance with claim 1 , wherein the cahedral is a dihedral or anhedral.
7. The airfoil in accordance with claim 6 , wherein said edge and said surface define an anhedral in addition to the dihedral.
8. The airfoil in accordance with claim 6 , wherein the sweep is a forward sweep or aft sweep.
9. The airfoil in accordance with claim 1 , wherein at least one of the cahedral or sweep is varied throughout at least a portion of the airfoil.
10. The airfoil in accordance with claim 1 , wherein said surface comprises a high-pressure surface, said airfoil further comprising a low-pressure surface opposite said high-pressure surface, said high-pressure surface and said low-pressure surface sloped throughout said distal portion to at least partly define the cahedral.
11. The airfoil in accordance with claim 10 , further comprising a shift, each of said high-pressure surface and said low-pressure surface having a curved shape adjacent said shift.
12. The airfoil in accordance with claim 1 , wherein said airfoil comprises at least one of the following: a single rotation propeller, an outlet guide vane, a fan blade, a rotor blade, a stator vane, a ducted fan blade, an unducted fan blade, a strut, a wind turbine blade, a propeller, an impeller, a diffuser vane, a return channel vane, a marine propeller, and a pylon.
13. A rotary machine, comprising:
at least one rotatable member;
a casing extending at least partly circumferentially around said at least one rotatable element; and
a propeller assembly adjacent said casing and drivingly coupled to said at least one rotatable member, said propeller assembly comprising:
a hub;
at least one blade extending radially from said hub, said at least one blade comprising:
a proximal end adjacent said hub;
a distal end opposite said proximal end;
an intermediate portion extending between said proximal end and said distal end;
a distal portion extending between said intermediate portion and said distal end;
an edge extending between said proximal end and said distal end; and
a surface extending between said proximal end and said distal end, said edge and said surface defining a sweep and a cahedral through said distal portion and at least a portion of said intermediate portion, wherein the distal portion extends over an acoustically active portion of the blade; and
wherein the acoustically active portion is defined by a region of the blade extending from the distal end to a location along the blade that generates about 10 to about 20 dB less noise than a location along the blade that generates a maximum level of noise.
14. The rotary machine in accordance with claim 13 , wherein the acoustically active portion of the blade is a region of the blade determined by multiplying an acoustic source strength distributed radially along the blade by a radiation efficiency along the blade.
15. The rotary machine in accordance with claim 13 , wherein said at least one blade defines a low pressure side and a high pressure side, said surface extending on the low pressure side of said at least one blade such that the cahedral is a dihedral.
16. The rotary machine in accordance with claim 13 , wherein the cahedral is a dihedral.
17. The rotary machine in accordance with claim 16 , wherein the dihedral extends on a suction side of said at least one blade and the sweep is an aft sweep.
18. The rotary machine in accordance with claim 13 , wherein at least one of the cahedral or sweep is varied throughout at least a portion of the blade.