Non-axisymmetric end wall contouring with forward mid-passage peak
A turbine section includes a pair of adjacent turbine airfoils and an endwall extending between the airfoils. The endwall includes a first feature spanning approximately twenty percent pitch and having a first depression with a first maximum depression located between twenty percent and sixty percent of an axial chord length of the first airfoil, a second feature adjacent the first feature with the second feature spanning approximately forty percent pitch and having a first peak with a maximum height located between twenty percent and sixty percent of the axial chord length of the first airfoil, and a third feature adjacent the second feature and first side of the second airfoil with the third feature spanning approximately forty percent pitch and having a second depression with a second maximum depression located between thirty percent and sixty percent of an axial chord length of the second airfoil.
1. A turbine section comprising:
a pair of adjacent turbine airfoils, each airfoil including a first side, a second side, a leading edge, a trailing edge, and an axial chord length extending between the leading edge and the trailing edge, the pair of turbine airfoils having a first airfoil and a second airfoil; and
an endwall extending between the second side of the first airfoil and the first side of the second airfoil, the endwall comprising:
a first feature adjacent the second side of the first airfoil between the leading edge and the trailing edge, the first feature spanning twenty percent pitch and having a first depression with a first maximum depression located only between twenty percent and sixty percent of the axial chord length of the first airfoil;
a second feature adjacent the first feature between the leading edge and the trailing edge of the first airfoil, the second feature spanning forty percent pitch and having a first peak with a maximum height located only between thirty-five percent and forty-five percent of the axial chord length of the first airfoil; and
a third feature adjacent the second feature and the first side of the second airfoil between the leading edge and the trailing edge, the third feature spanning forty percent pitch and having a second depression with a second maximum depression located only between thirty percent and sixty percent of the axial chord length of the second airfoil.
2. The turbine section of claim 1 , wherein the turbine section is a power turbine section.
3. The turbine section of claim 1 , wherein the pair of airfoils are incident tolerant airfoils.
4. The turbine section of claim 1 , wherein the first side of each of the pair of airfoils is a suction side and the second side of each of the pair of airfoils is a pressure side.
5. The turbine section of claim 1 , wherein the first maximum depression is located between thirty-five and forty-five percent of the axial chord length of the first airfoil.
6. The turbine section of claim 1 , wherein the second maximum depression is located between forty-five and fifty-five percent of the axial chord length of the second airfoil.
7. The turbine section of claim 1 , wherein the endwall extends between an inner diameter of the pair of airfoils.
8. The turbine section of claim 1 , wherein at least a portion of the third feature extends axially rearward of the trailing edge of the second airfoil.
9. The turbine section of claim 1 , wherein the pair of airfoils are turbine blades.
10. The turbine section of claim 1 , wherein the second feature extends from twenty percent to sixty percent pitch as measured from the second side of the first airfoil and the third feature extends from sixty percent to one-hundred percent pitch as measured from the second side of the first airfoil.
11. The turbine section of claim 1 , wherein at least one of the first feature, the second feature, or the third feature includes a flat portion along the first depression, the first peak, or the second depression, respectively.
12. A gas turbine engine comprising:
a variable speed power turbine section;
an annular turbine stage;
a plurality of airfoils within the annular turbine stage and each having a first side, a second side, a leading edge, a trailing edge, the plurality of airfoils having a first airfoil and a second airfoil; and
an endwall extending between the second side of the first airfoil and the first side of the second airfoil, the endwall comprising:
a first feature adjacent the second side of the first airfoil between the leading edge and the trailing edge, the first feature spanning twenty percent pitch and having a first depression with a first maximum depression located only between twenty percent and sixty percent of an axial chord length of the first airfoil;
a second feature adjacent the first feature between the leading edge and the trailing edge of the first airfoil, the second feature spanning forty percent pitch and having a first peak with a maximum height located only between thirty-five percent and forty-five of the axial chord length of the first airfoil; and
a third feature adjacent the second feature and first side of the second airfoil between the leading edge and the trailing edge, the third feature spanning forty percent pitch and having a second depression with a second maximum depression located only between thirty percent and sixty percent of an axial chord length of the second airfoil.
13. The gas turbine engine of claim 12 , wherein the plurality of airfoils are incident tolerant airfoils.
14. The gas turbine engine of claim 12 , wherein the first side of each of the plurality of airfoils is a suction side and the second side of each of the plurality of airfoils is a pressure side.
15. The gas turbine engine of claim 12 , wherein the first maximum depression is located between thirty-five and forty-five percent of the axial chord length of the first airfoil.
16. The gas turbine engine of claim 12 , wherein the second maximum depression is located between forty-five and fifty-five percent of the axial chord length of the second airfoil.
17. The gas turbine engine of claim 12 , wherein the endwall extends between an inner diameter of the plurality of airfoils.
18. The gas turbine engine of claim 12 , wherein at least a portion of the third feature extends axially rearward of the trailing edge of the second airfoil.
19. The gas turbine engine of claim 12 , wherein the plurality of airfoils comprise a turbine rotor.
20. The gas turbine engine of claim 12 , wherein at least one of the first feature, the second feature, or the third feature includes a flat portion along an adjacent one of the first feature, the second feature, or the third feature.