Gas turbine diffuser strut including coanda flow injection

Patent metadata

Field	Value
Publication number	US-9488191-B2
Application number	US-201314067173-A
Country	US
Kind code	B2
Filing date	Oct 30, 2013
Priority date	Oct 30, 2013
Publication date	Nov 8, 2016
Grant date	Nov 8, 2016

Abstract

An exhaust diffuser comprising an inner boundary and an outer boundary forming an annular gas path, and a plurality of strut structures extending radially within the gas path. Each of the strut structures include pressure and suction side walls, and a plurality of radially spaced flow injectors are formed in at least one of the pressure and suction side walls for injecting a fluid flow into the gas path adjacent to the strut structure. At least two fluid supply conduits provide a fluid flow to respective radially spaced flow injectors, and a flow control device is associated with each of the conduits to independently control a fluid flow from a fluid source to each of the radially spaced flow injectors.

First claim

What is claimed is:

1. An exhaust diffuser for a gas turbine engine, comprising:
an inner boundary and an outer boundary forming an annular gas path;
a plurality of strut structures extending radially between the inner boundary and the outer boundary and located within the gas path downstream of a last row of rotating blades of the gas turbine engine;
each of the strut structures including pressure and suction side walls extending in a downstream axial direction from a leading edge toward a downstream trailing edge of the strut structure;
a plurality of radially spaced flow injectors formed in at least one of the pressure and suction side walls, the flow injectors injecting a respective fluid flow into the gas path adjacent to the strut structure, the flow injectors being oriented so as to direct the respective fluid flow substantially parallel to an outer surface of the at least one of the pressure and suction side walls in a direction along an exhaust flow, producing a Coanda jet flow adjacent to the at least one of the pressure and suction side walls, to entrain and accelerate a portion of the exhaust flow to result in substantially attached flow along the at least one of the pressure and suction side walls; and
at least two fluid supply conduits connected to provide a fluid flow to respective radially spaced flow injectors, and a flow control device associated with each of the conduits to independently control a fluid flow from a fluid source to each the radially spaced flow injectors, the radially spaced flow injectors being associated with respective plenums within the strut structure which are separated from each other.

2. The exhaust diffuser of claim 1 , wherein the at least two fluid supply conduits include at least a first conduit supplying a fluid flow to a first flow injector adjacent to the inner boundary and a second conduit supplying a fluid flow to a second flow injector adjacent to the outer boundary.

3. The exhaust diffuser of claim 2 , wherein the first and second flow injectors are elongated in a radial direction to provide a Coanda flow to radially extending sections of the at least one of the pressure and suction side walls.

4. The exhaust diffuser of claim 3 , wherein each of the first and second flow injectors are defined by a continuous elongated slot.

5. The exhaust diffuser of claim 3 , wherein each of the first and second flow injectors are defined by a plurality of discrete openings.

6. The exhaust diffuser of claim 2 , including a further flow conduit supplying a fluid flow to a flow injector located radially midway between the first and second flow injectors.

7. The exhaust diffuser of claim 3 , wherein the flow injectors are located extending radially adjacent to the leading edge of the strut structure.

8. An exhaust diffuser for a gas turbine engine, comprising:
an inner boundary and an outer boundary forming an annular gas path;
a plurality of struts extending radially between the inner boundary and the outer boundary and located within the gas path downstream of a last row of rotating blades of the gas turbine engine;
an airfoil shaped strut shield surrounding each of the struts, each of the strut shields including pressure and suction side walls extending in a downstream axial direction from a leading edge toward a downstream trailing edge of the strut shield;
a plurality of radially spaced flow injectors formed in the suction side wall, the flow injectors injecting a respective fluid flow into the gas path adjacent to the strut shield, the flow injectors being oriented so as to direct the respective fluid flow substantially parallel to an outer surface of the suction side wall in a direction along an exhaust flow, to produce a Coanda jet flow adjacent to the suction side wall to entrain and accelerate a portion of the exhaust flow to result in substantially attached flow along the suction side wall; and
each of the radially spaced flow injectors are connected to a respective fluid supply conduit to provide a fluid flow to the flow injectors, and a flow control device associated with each of the conduits to independently increase or decrease the mass flow rate of a fluid flow from a pressurized fluid source to the radially spaced flow injectors, the radially spaced flow injectors being associated with respective plenums within the strut structure which are separated from each other.

9. The exhaust diffuser of claim 8 , wherein the flow injectors are elongated in a radial direction to provide a Coanda flow to radially extending sections of the suction side wall.

10. The exhaust diffuser of claim 9 , wherein each of the first and second flow injectors are defined by a continuous elongated slot.

11. The exhaust diffuser of claim 9 , wherein each of the first and second flow injectors are defined by a plurality of discrete openings.

12. The exhaust diffuser of claim 8 , wherein the control devices are configured to change the fluid flow to the flow injectors to provide different mass flows along the radial extent of the strut shield, as an operating condition of the engine is changed.

13. The exhaust diffuser of claim 8 , wherein the flow injectors are located extending radially adjacent to the leading edge of the strut shield.

14. A method of exhaust diffusion in a turbine engine comprising the steps of:
providing a turbine engine having a turbine section and an exhaust diffuser section, the exhaust diffuser section including an inner boundary and an outer boundary spaced radially from the inner boundary so that a flow path is defined therebetween, and strut structures extending radially through the flow path between the inner and outer boundaries, the strut structures each including a pressure side wall and a suction side wall extending axially in a direction of flow through the flow path and a plurality of radially spaced flow injectors formed in at least one of the pressure and suction side walls;
supplying a flow of turbine exhaust gas to the flow path;
supplying a first Coanda jet flow through a first flow injector of the plurality of flow injectors, at a first mass flow rate along said at least one of the pressure and suction side walls at a first location adjacent to the inner boundary;
supplying a second Coanda through a second flow injector of the plurality of flow injectors, jet flow at second mass flow rate along said at least one of the pressure and suction side walls at a second location radially outward from the first location;
wherein the first and second Coanda jet flows are substantially parallel to an outer surface of said at least one of the pressure and suction side walls in a direction along an exhaust flow,
wherein a fluid supply to the first Coanda jet flow is controlled separately from a fluid supply to the second Coanda jet flow, the first and second flow injectors being associated with respective plenums within the strut structure which are separated from each other.

15. The method of claim 14 , wherein the first mass flow rate of the first Coanda jet flow is different than the second mass flow rate of the second Coanda jet flow.

16. The method of claim 15 , including changing the mass flow rate of one of the first and second Coanda jet flows relative to the other of the first and second Coanda jet flows.

17. The method of claim 14 , wherein the first and second Coanda jet flows exit from the strut structure at a location adjacent to an upstream leading edge of the strut structure.

Assignees

• Matys Pawel
• Siemens Ag

Inventors

• Matys Pawel

Classifications

• F01D5/146 Primary

  of blades with tandem configuration, split blades or slotted blades · CPC title

• F01D25/305

  with fluid, e.g. liquid injection · CPC title

• F05D2270/173

  by the Coanda effect · CPC title

• F04D29/542 Primary

  Bladed diffusers (fixing blades to stators F01D9/042) · CPC title