Gas turbine compressor stator vane assembly

Abstract

A stator vane assembly for a compressor of a gas turbine, in particular of an aircraft engine, including a plurality of stator vanes whose airfoil sections form a stagger angle with an axis of rotation of the compressor, which stagger angle varies along a duct height of the stator vane assembly. Along the duct height from the inside to the outside, the stagger angle increases to a local maximum in a second section adjoining a first, radially innermost section, and decreases to an outer local minimum in a third section adjoining this second section and, along the duct height from the inside to the outside, the stagger angle decreases from the initial value to an inner local minimum in the first, radially innermost section and/or increases from the outer local minimum to a final value in a fourth, radially outermost section adjoining the third section.

Claims

1. A stator vane assembly for a compressor of a gas turbine comprising: a plurality of stator vanes whose airfoil sections form a stagger angle with an axis of rotation of the compressor, the stagger angle varying along a duct height of the stator vane assembly, wherein along the duct height between a radially innermost initial value and a radially outermost final value, the stagger angle increases to a local maximum in a second section adjoining a first, radially innermost section, and decreases to an outer local minimum in a third section adjoining said second section, and wherein, along the duct height from the inside to the outside, the stagger angle decreases from the initial value to an inner local minimum in the first, radially innermost section or increases from the outer local minimum to the final value in a fourth, radially outermost section adjoining the third section.

2. The stator vane assembly as recited in claim 1 wherein the stagger angle decreases monotonically in the first or third section or increases monotonically in the second or fourth section.

3. The stator vane assembly as recited in claim 2 wherein the monotonical decrease or increase is strictly monotonical.

4. The stator vane assembly as recited in claim 1 wherein the local maximum is greater than the initial value or the final value.

5. The stator vane assembly as recited in claim 4 wherein the local maximum is at least 2.5° and no more than 7°.

6. The stator vane assembly as recited in claim 1 wherein the initial value is smaller than the final value.

7. The stator vane assembly as recited in claim 1 wherein the initial value is at least 1° and no more than 5° smaller than the final value.

8. The stator vane assembly as recited in claim 1 wherein the initial value is at least 1° and no more than 2.5° greater than the inner local minimum or the final value is at least 1° and no more than 2.5° greater than the outer local minimum.

9. The stator vane assembly as recited in claim 1 wherein the local maximum is at least 3.5° and no more than 9.5° greater than the inner or outer local minimum.

10. The stator vane assembly as recited in claim 1 wherein the height of the first or fourth section is at least 3% and no more than 25% of the total duct height between the initial value and the final value.

11. The stator vane assembly as recited in claim 1 wherein the local maximum is located between 25% and 75% of the total duct height between the initial value and the final value.

12. The stator vane assembly as recited in claim 1 wherein the leading edge of at least one of the stator vanes is curved toward a suction side of the stator vane.

13. The stator vane assembly as recited in claim 12 wherein the leading edge is strictly convexly curved.

14. An aircraft engine comprising the stator vane assembly as recited in claim 1.

15. A compressor for a gas turbine comprising: at least one stator vane assembly as recited in claim 1.

16. The compressor as recited in claim 15 wherein the stator vane assembly is a downstream stator vane assembly.

17. An aircraft engine comprising the compressor as recited in claim 15.

18. A gas turbine comprising the compressor as recited in claim 15.

19. The gas turbine as recited in claim 18 wherein the compressor is a downstream compressor.

20. An aircraft engine comprising the gas turbine as recited in claim 18.

21. The stator vane assembly as recited in claim 1 wherein, along the duct height from the inside to the outside, the stagger angle decreases from the initial value to the inner local minimum in the first, radially innermost section.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantageous features of the present invention will be apparent from the dependent claims and the following description of preferred embodiments. To this end, the drawings show, partly in schematic form, in:

(2) FIG. 1: an airfoil section of a stator vane of a stator vane assembly of a compressor of a gas turbine according to an embodiment of the present invention; and in

(3) FIG. 2: the curve of a stagger angle of the stator vane of FIG. 1 as a function of a duct height.

(4) FIG. 3 shows schematically a stator vane assembly 100 with leading edges curved strictly convexly toward a suction side.

DETAILED DESCRIPTION

(5) FIG. 1 shows an airfoil section 1 of a stator vane of a stator vane assembly 100 (See FIG. 3) of a compressor of a gas turbine according to an embodiment of the present invention, where a chord 2 forms a stagger angle β with an axis of rotation 3 of the compressor.

(6) FIG. 2 shows the curve of the stagger angle β of the stator vane of FIG. 1 as a function of a duct height h.

(7) Stagger angle β varies along duct height h in a radial direction from the inside to the outside (from left to right in FIG. 2) in such a way that in a first, radially innermost section h.sub.1, it decreases strictly monotonically from an initial value A to an inner local minimum IM, that in an adjoining second section h.sub.2, it increases strictly monotonically to a local maximum Max, that in an adjoining third section h.sub.3, it decreases strictly monotonically to an outer local minimum AM, and that in an adjoining fourth, radially outermost section h.sub.4, it increases strictly monotonically from the outer local minimum to a final value E.

(8) Local maximum Max is 3.8° greater than initial value A and 5.7° greater than final value E. Initial value A is 1.9° greater than final value E. Initial value A is 1.4° greater than inner local minimum IM, and final value E is 1.4° greater than outer local minimum AM. Local maximum Max is 5.2° greater than inner local minimum IM and 7.1° greater than outer local minimum AM. The heights of the first and fourth sections are each 7% of the total duct height, and the heights of the second and third sections are each 43%, so that the local maximum is located at 50% of the total duct height.

(9) Although the above is a description of exemplary embodiments, it should be noted that many modifications are possible. It should also be appreciated that the exemplary embodiments are only examples, and are not intended to limit scope, applicability, or configuration in any way. Rather, the foregoing description provides those skilled in the art with a convenient road map for implementing at least one exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described without departing from the scope of protection set forth in the appended claims and their equivalent combinations of features.

LIST OF REFERENCE NUMERALS

(10) 1 airfoil section

(11) 2 chord

(12) 3 axis of rotation

(13) β stagger angle

(14) h duct height

(15) h.sub.1/2/3/4 first/second/third/fourth section

(16) A initial value

(17) E final value

(18) IM inner local minimum

(19) AM outer local minimum

(20) Max local maximum