Flow straightener and mixer

1. Flow straightener and mixing device comprising:

a structure with walls having a longitudinal axis;

an inlet area;

an outlet area in a main flow direction; and

at least two streamlined bodies, which are arranged in the flow straightener and mixing device, each having a streamlined cross-sectional profile, which extends with a longitudinal direction perpendicularly or at an inclination to the main flow direction of the flow straightener and mixing device, wherein a leading edge area of each streamlined body has a profile, which is oriented parallel to the main flow direction at a leading edge position, and wherein, with reference to a central plane of the streamlined bodies, the trailing edges are provided with at least two lobes in opposite transverse directions, wherein a transverse deflection from the central plane of two adjacent streamlined bodies, which form the lobes, are inverted, and wherein a transition from a planar leading edge region to the deflection is smooth with a surface curvature representing a function with a continuous first derivative, and

at least one of the lobes of the streamlined bodies is configured as an injection device with at least one nozzle for introducing at least one fuel into a burner.

2. Flow straightener and mixing device according to claim 1 , wherein the leading edge region of the streamlined body has an aerodynamic profile, which turns from an inclined orientation relative to the longitudinal axis of the flow straightener and mixing devices to an orientation, which is parallel to the longitudinal axis of the flow straightener and mixing device in an upstream half of the streamlined body.

3. Flow straightener and mixing device according to claim 1 , wherein a transverse displacement of the streamlined body forming the lobes is only at most in a downstream two thirds of a length of the streamlined body.

4. Flow straightener and mixing device according to claim 1 , wherein a distance between central planes of two streamlined bodies is at least 1.2 times the height (h) of the lobes.

5. Flow straightener and mixing device according to claim 1 , comprising:

a rectangular or trapezoidal cross section extending along the longitudinal axis, which is defined by four walls, with the at least two streamlined bodies extending from one wall to an opposing wall.

6. Flow straightener and mixing device according to claim 1 , comprising:

an annular cross section extending along the longitudinal axis with an inner wall and an outer wall, which are concentric to each other, and with the at least two streamlined bodies extending from the inner wall to the outer wall.

7. A flow straightener and mixing device according to claim 1 , wherein at least one fuel nozzle is located at the trailing edge of at least one of the streamlined bodies.

8. A flow straightener and mixing device according to claim 7 , comprising:

at least two fuel nozzles located at the trailing edge of at least one of the streamlined bodies located essentially at apexes of the lobes, wherein at each apex or at every second apex along the trailing edge there is located a fuel nozzle, and/or wherein a fuel nozzle is located essentially on the central plane of the streamlined body, wherein at each position, where the lobed trailing edge crosses the central plane, there is located a fuel nozzle.

9. A flow straightener and mixing device according to claim 1 , comprising:

at least two fuel nozzles located at the trailing edge of at least one of the streamlined bodies and distributed along the trailing edge, wherein at least at one position, where the lobed trailing edge crosses the central plane, there is located a fuel nozzle for injection of a liquid fuel, and wherein at least one fuel nozzle for injection of a gaseous fuel is located essentially at the turning points between two lobes.

10. A flow straightener and mixing device according to claim 1 , wherein downstream of said streamlined bodies a mixing zone is located, and wherein at and/or downstream of said streamlined bodies, the cross-section of said mixing zone is reduced, wherein this reduction is at least 10%, compared to the flow cross-section upstream of said streamlined bodies.

11. A flow straightener and mixing device according to claim 1 , wherein the body is provided with cooling elements represented by internal circulation of cooling medium along the sidewalls of the body and/or by film cooling holes located near the trailing edge, and wherein the cooling elements are fed with air from the carrier gas feed also used for the fuel injection.

12. A flow straightener and mixing device according to claim 1 , wherein the fuel nozzles are circular and/or are elongated slot nozzles extending along the trailing edge of the streamlined body and/or comprise a first nozzle for injection of liquid fuel, and/or a second nozzle for injection of a gaseous fuel and a third nozzle for injection of carrier air, which encloses the first nozzle and/or the second nozzle.

13. Flow straightener and mixing device according to claim 1 , wherein a distance between central planes of two streamlined bodies is at least 1.5 times the height (h) of the lobes.

14. Method for operating a flow straightener and mixing device in combination with a burner for a combination chamber of a gas turbine, the fuel straightener and mixing device having:

a structure with walls having a longitudinal axis;

an inlet area;

an outlet area in a main flow direction;

at least two streamlined bodies, which are arranged in the flow straightener and mixing device, each having a streamlined cross-sectional profile, which extends with a longitudinal direction perpendicularly or at an inclination to the main flow direction of the flow straightener and mixing device, wherein a leading edge area of each streamlined body has a profile, which is oriented parallel to the main flow direction at a leading edge position, and wherein, with reference to a central plane of the streamlined bodies the trailing edges are provided with at least two lobes in opposite transverse directions, wherein a transverse deflection from the central plane of two adjacent streamlined bodies, which form the lobes, are inverted, and wherein a transition from a planar leading edge region to the deflection is smooth with a surface curvature representing a function with a continuous first derivative, and at least one of the lobes of the streamlined bodies is configured as an injection device with at least one nozzle for introducing at least one fuel into a burner, wherein the method comprises:

determining a number of fuel injection nozzles through which fuel is injected as function of total injected fuel flow; and

injecting fuel through the fuel injection nozzles.

15. Method for operating a flow straightener and mixing device according to claim 14 , comprising:

below a fuel flow threshold, injecting fuel flow through every second fuel nozzle of a streamlined body and/or only injecting fuel through the fuel nozzles of every second or third streamlined body of the burner.

16. Method for operating a flow straightener and mixing device according to claim 14 , comprising:

conducting combustion of MBtu fuel and/or conducting combustion of hydrogen rich fuel.

17. Method for operating a flow straightener and mixing device according to claim 14 for at least one burner for a combustion chamber of a gas turbine group, wherein the gas turbine group comprises:

at least one compressor unit, a first combustion chamber for generating working gas, wherein the first combustion chamber is connected to receive compressed air from the compressor unit, the first combustion chamber being an annular combustion chamber having a plurality of premixing burners, a first turbine connected to received working gas from the first combustion chamber, a second turbine, a second combustion chamber connected to receive exhausted working gas from the first turbine and deliver working gas to the second turbine, wherein the second chamber comprises an annular duct forming a combustion space extending in a flow direction from outlet of the first turbine to an inlet of the second turbine, and means for introducing fuel into the second combustion chamber for self-ignition of the fuel.

18. Method for operating a flow straightener and mixing device according to claim 14 for at least one burner for a combustion chamber of a gas turbine group, wherein the gas turbine group comprises:

at least one compressor;

at least one combustion chamber; and

at least one turbine, wherein the rotating parts of the compressor and of the turbine are arranged on a common rotor.

19. Method for operating a flow straightener and mixing device according to claim 14 for at least one burner for a combustion chamber of a gas turbine group, wherein the gas turbine group comprises:

at least one compressor;

a plurality of cylindrical or quasi-cylindrical combustors arranged in an annular or quasi-annular array on a common rotor; and

at least one turbine, and wherein the combustor comprises at least a primary and secondary combustion zones.