Diffuser with strut-induced vortex mixing

1. A gas turbine engine having a turbine exhaust section comprising:

a pair of concentrically spaced rings;

a plurality of strut structures extending radially between the rings, interconnecting and supporting the rings;

the plurality of strut structures supported downstream of a last row of rotating blades and comprising a main body portion having an elongated chordal dimension in the direction of an axial gas flow through the engine and defining a chordal axis extending in a downstream direction from an upstream end of the main body portion toward a downstream end of the strut structure; and

a trailing edge flap located at the downstream end of each main body portion, the trailing edge flap including first and second span-wise portions, the first span-wise portion oriented to direct flow at an angle relative to the chordal axis of the main body portion and the second span-wise portion oriented to direct flow in a direction that is at a different angle than the angle of the first span-wise portion,

wherein the entirety of the first span-wise portion defines a flap angle in a direction to a first side of the chordal axis, and wherein the first and second span-wise portions are oriented independently of each other such that the entirety of the second span-wise portion defines a flap angle in a direction to a second, opposite side of the chordal axis from the first side.

2. The gas turbine engine of claim 1 , wherein the direction of the flap angle of the first span-wise portions alternates relative to circumferentially adjacent first span-wise portions, and the direction of the flap angle of the second span-wise portions alternates relative to circumferentially adjacent second span-wise portions.

3. The gas turbine engine of claim 1 , wherein the direction of the flap angle of each of the first span-wise portions are all oriented in the same direction, and the direction of the flap angle of each of the second span-wise portions are all oriented in the same direction.

4. The gas turbine engine of claim 1 , wherein the first span-wise portion extends from a span-wise intermediate location toward an inner one of the rings along the plurality of strut structures and the second span-wise portion extends from the intermediate location toward an outer one of the rings.

5. The gas turbine engine of claim 4 , wherein the span-wise intermediate location is at the mid-span of the main body.

6. The gas turbine engine of claim 1 , wherein the plurality of strut structures include struts surrounded by an airfoil shaped shield, and the plurality of strut structures are located at an upstream end of an exhaust diffuser for the engine.

7. The gas turbine engine of claim 1 , wherein the first and second span-wise portions are movable relative to the main body, and the first span-wise portion is movable independently of the second span-wise portion.

8. The gas turbine engine of claim 1 , including a planar divider, lying in an axially and circumferentially extending plane intersecting a span-wise transition between the first and second span-wise portions limiting radial flow between the first and second span-wise portions.

9. An exhaust diffuser for a gas turbine engine, comprising:

an inner shroud and an outer shroud forming an annular gas path;

a plurality of struts connecting the inner shroud to the outer shroud and located within the gas path downstream of a last row of rotating blades;

airfoil shaped shields surrounding the struts, each of the shields comprise a main body having an upstream leading edge defining a chordal axis extending in a downstream axial direction from the leading edge toward a downstream end of the shield; and

a trailing edge flap located at the downstream end of each shield, the trailing edge flap including first and second span-wise portions, the first span-wise portion oriented to direct flow at an angle relative to the chordal axis of the main body and the second span-wise portion oriented to direct flow in a direction that is at a different angle than the angle of first span-wise portion,

wherein for each shield, the entirety of the first span-wise portion defines a flap angle in a direction to a first side of the chordal axis, wherein the first and second span-wise portions are oriented independently of each other such that the entirety of the second span-wise portion defines a flap angle in a direction to a second, opposite side of the chordal axis from the first side.

10. The exhaust diffuser of claim 9 , wherein the direction of the flap angle of the first span-wise portions alternates relative to circumferentially adjacent first span-wise portions, and the direction of the flap angle of the second span-wise portions alternates relative to circumferentially adjacent second span-wise portions.

11. The exhaust diffuser of claim 9 , wherein the direction of the flap angle of each of the first span-wise portions are all oriented in the same direction, and the direction of the flap angle of each of the second span-wise portions are all oriented in the same direction.

12. The exhaust diffuser of claim 9 , wherein the first span-wise portion extends from a span-wise intermediate location toward the inner shroud along the shield and the second span-wise portion extends from the intermediate location toward the outer shroud.

13. The exhaust diffuser of claim 12 , wherein the span-wise intermediate location is at the mid-span of the shield.

14. The exhaust diffuser of claim 9 , wherein the first and second span-wise portions are movable relative to the chordal axis.

15. The exhaust diffuser of claim 14 , including actuators connected to the first and second span-wise portions to actuate the first span-wise portion in movement independently of the second span-wise portion.

16. The exhaust diffuser of claim 9 , including a planar divider, lying in an axially and circumferentially extending plane intersecting a span-wise transition between the first and second span-wise portions limiting radial flow between the first and second span-wise portions.

17. An exhaust diffuser for a gas turbine engine, comprising:

an inner shroud and an outer shroud forming an annular gas path;

a plurality of struts connecting the inner shroud to the outer shroud and located within the gas path downstream of a last row of rotating blades;

airfoil shaped shields surrounding the struts, each of the shields comprise a main body having an upstream leading edge defining a chordal axis extending in a downstream axial direction from the leading edge toward a downstream end of the shield; and

a trailing edge flap located at the downstream end of each shield, the trailing edge flap including first and second span-wise portions, the first span-wise portion oriented to direct flow at an angle relative to the chordal axis of the main body and the second span-wise portion oriented to direct flow in a direction that is at a different angle than the angle of first span-wise portion,

wherein for each shield, the first span-wise portion defines a flap angle in a direction to a first side of the chordal axis, and the second span-wise portion defines a flap angle in a direction to a second, opposite side of the chordal axis from the first side, and

wherein the direction of the flap angle of the first span-wise portions alternates relative to circumferentially adjacent first span-wise portions, and the direction of the flap angle of the second span-wise portions alternates relative to circumferentially adjacent second span-wise portions.