Fuel nozzle having aerodynamically shaped helical turning vanes
A fuel nozzle for a gas turbine engine is disclosed which includes a nozzle body having a longitudinal axis, an elongated annular air passage defined within the nozzle body, and a plurality of circumferentially spaced apart axially extending swirl vanes disposed within the annular air passage, wherein each swirl vane has multiple joined leads and a variable thickness along the axial extent thereof.
1. A fuel nozzle for a gas turbine engine comprising:
a) a nozzle body having a longitudinal axis;
b) an annular air passage defined within the nozzle body; and
c) a plurality of circumferentially spaced apart axially extending helically pitched swirl vanes disposed within the annular air passage, each swirl vane having multiple joined helical leads and a variable thickness along the axial extent thereof.
2. A fuel nozzle as recited in claim 1 , wherein each swirl vane includes an upstream vane section having a leading edge surface and a downstream vane section having a trailing edge surface.
3. A fuel nozzle as recited in claim 2 , wherein the leading edge surface of the upstream vane section of each vane is disposed at an angle relative to the longitudinal axis of the nozzle body.
4. A fuel nozzle as recited in claim 3 , wherein the angle of the leading edge surface of each vane defines an initial pitch along the axial extent of the upstream vane section.
5. A fuel nozzle as recited in claim 2 , wherein the downstream vane section has a continuously varying pitch along the axial extent thereof.
6. A fuel nozzle as recited in claim 2 , wherein the downstream vane section has a constant pitch along an axial extent thereof.
7. A fuel nozzle as recited in claim 2 , wherein each vane includes a transitional vane section that blends the upstream vane section into the downstream vane section.
8. A fuel nozzle as recited in claim 7 , wherein each vane has a maximum normal thickness associated with the transitional vane section.
9. A fuel nozzle as recited in claim 8 , wherein normal vane thickness varies from the transitional vane section to the trailing edge surface of the vane.
10. A fuel nozzle as recited in claim 8 , wherein normal vane thickness remains constant for at a least an axial segment of the vane from the transitional vane section to the trailing edge surface of the vane.
11. A fuel nozzle as recited in claim 7 , wherein normal vane thickness varies from the transitional vane section to the leading edge surface of the vane.
12. A fuel nozzle as recited in claim 7 , wherein normal vane thickness remains constant from the transitional vane section to the leading edge surface of the vane.
13. A fuel nozzle as recited in claim 1 , further comprising a fuel circuit defined within the nozzle body adjacent the annular air passage.