Turbine airfoil
An airfoil is provided and includes a pressure surface and a suction surface. Radially corresponding surface characteristics of the pressure and suction surfaces at a spanwise local portion of the airfoil are formed to cooperatively define at least one of a camber line and a thickness distribution plot of the airfoil as having a radius of curvature with at least two sign changes. The number of sign changes decreases along a radial dimension of the airfoil measured from the spanwise local portion.
1. An airfoil for extracting energy in a turbine engine, comprising:
a pressure surface; and
a suction surface,
radially corresponding surface characteristics of the pressure and suction surfaces at a spanwise local portion of the airfoil being formed to cooperatively define a camber line of the airfoil as having a radius of curvature with at least two sign changes,
the number of sign changes decreasing along a radial dimension of the airfoil measured from the spanwise local portion.
2. The airfoil according to claim 1 , wherein the surface characteristics form an irregular nose section proximate to a leading edge of the airfoil.
3. The airfoil according to claim 2 , wherein features of the irregular nose section become decreasingly prominent along a radial dimension of the airfoil.
4. The airfoil according to claim 2 , wherein the irregular nose section is bulbous at a radial position of the airfoil and becomes decreasingly bulbous along a radial dimension of the airfoil.
5. The airfoil according to claim 1 , wherein the surface characteristics form a tail section proximate to a trailing edge of the airfoil.
6. The airfoil according to claim 5 , wherein features of the tail section become decreasingly prominent along a radial dimension of the airfoil.
7. The airfoil according to claim 5 , wherein the tail section curves in a direction of turbine stage rotation at a radial position of the airfoil with an amount of curvature decreasing along a radial dimension of the airfoil.
8. The airfoil according to claim 1 , wherein the surface characteristics cooperatively define a thickness distribution plot of the airfoil as having a radius of curvature with at least two sign changes.
9. The airfoil according to claim 1 , wherein a chord length of the airfoil is substantially uniform at two or more radial positions at which the surface characteristics cooperatively define the camber line as having a radius of curvature with at least two sign changes.
10. An airfoil for extracting energy in a turbine engine, comprising:
a pressure surface; and
a suction surface,
radially corresponding surface characteristics of the pressure and suction surfaces at a spanwise local portion of the airfoil being formed to cooperatively define a thickness distribution plot of the airfoil as having a radius of curvature with at least two sign changes,
the number of sign changes decreasing along a radial dimension of the airfoil measured from the spanwise local portion.
11. The airfoil according to claim 10 , wherein the surface characteristics form an irregular nose section proximate to a leading edge of the airfoil.
12. The airfoil according to claim 11 , wherein features of the irregular nose section become decreasingly prominent along a radial dimension of the airfoil.
13. The airfoil according to claim 11 , wherein the irregular nose section is bulbous at a radial position of the airfoil and becomes decreasingly bulbous along a radial dimension of the airfoil.
14. The airfoil according to claim 11 , wherein the surface characteristics form a tail section proximate to a trailing edge of the airfoil.
15. The airfoil according to claim 14 , wherein features of the tail section become decreasingly prominent along a radial dimension of the airfoil.
16. The airfoil according to claim 14 , wherein the tail section curves in a direction of turbine stage rotation at a radial position of the airfoil with an amount of curvature decreasing along a radial dimension of the airfoil.
17. The airfoil according to claim 10 , wherein the surface characteristics cooperatively define a camber line having a radius of curvature with at least two sign changes.
18. The airfoil according to claim 10 , wherein a chord length of the airfoil is substantially uniform at two or more radial positions at which the radially corresponding surface characteristics cooperatively define the thickness distribution plot as having a radius of curvature with at least two sign changes.
19. An airfoil for extracting energy in a turbine engine, comprising:
a pressure surface having pressure surface characteristics; and
a suction surface having suction surface characteristics,
the pressure and suction surface characteristics being formed at a spanwise local portion of the airfoil to cooperatively define at least one of a camber line of the airfoil and a thickness distribution plot of the airfoil as having a radius of curvature with at least two sign changes,
the number of sign changes decreasing to zero along a radial dimension of the airfoil measured from the spanwise local portion.
20. The airfoil according to claim 19 , wherein a chord length of the airfoil is substantially uniform at the spanwise local portion and at another spanwise portion spaced from the spanwise local portion along the radial dimension.