AIRFOIL FOR GAS TURBINE ENGINE

• US 20130236319A1
• Filed: 03/08/2012
• Published: 09/12/2013
• Est. Priority Date: 03/08/2012
• Status: Active Grant

• Current Assignee: Pratt & Whitney Canada Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Peter Townsend
• Inventors: ROCKARTS, Sean, TOWNSEND, Peter
• Granted Patent: US 10,087,764 B2
• Time in Patent Office: Days
• US Class Current: 416/223.R
• CPC Class Codes: F01D 5/141 Shape, i.e. outer, aerodynamic form F01D5/148 - F01D5/20 take precedence; blade construction F01D5/147
• CPC Class Codes: F01D 5/20 Specially-shaped blade tips to seal space between tips and stator F01D5/225 takes precedence
• CPC Class Codes: F05D 2240/305 related to the pressure side of a rotor blade
• CPC Class Codes: F05D 2240/306 related to the suction side of a rotor blade

Abstract

An airfoil for a rotor blade or a stator vane of a gas turbine engine having a tip extension extending one or both of the suction and pressure side surfaces adjacent the tip. The tip extension defines a thickness at the tip larger than the true thickness of the airfoil. The tip extension includes a side transitional surface substantially defined along a curve extending tangentially from the corresponding side surface. The tip extension defines a gradual increase in the thickness over a portion of the airfoil having a radial dimension corresponding to at least 2 times the true thickness.

Claims

1. An airfoil for a rotor blade or a stator vane of a gas turbine engine, the airfoil comprising:

a suction side surface and a pressure side surface extending between a root and a tip, the side surfaces being interconnected by opposed leading and trailing edges with a chord being defined between the leading edge and the trailing edge and a radial direction being defined from the root to the tip;

a tip extension extending from at least one of the suction side surface and the pressure side surface adjacent the tip and defining a thickness at the tip larger than a true thickness of the airfoil, the true thickness being defined transversely to the chord around a mid point thereof and between the root and the tip extension; and

the tip extension including a side transitional surface substantially defined along a curve extending tangentially from the at least one of the suction side surface and the pressure side surface, the tip extension defining a gradual increase in the thickness over a portion of the airfoil having a radial dimension corresponding to at least 2 times the true thickness.

2. The airfoil according to claim 1 wherein the radial dimension corresponds to from 2 to 5 times the true thickness.

3. The airfoil according to claim 1 wherein the curve along which the side transitional surface is substantially defined corresponds to an arc of circle, a quadratic equation, or an equation of higher degree than a quadratic equation.

4. The airfoil according to claim 1 wherein the tip extension is provided on both the suction side surface and the pressure side surface.

5. The airfoil according to claim 1 wherein each tip extension includes a curved tip transitional surface extending between the tip and the side transitional surface, the tip transitional surface being substantially defined along a curve extending tangentially to the side transitional surface and corresponding to an arc of circle, a quadratic equation, or an equation of higher degree than a quadratic equation.

6. The airfoil according to claim 1, wherein each tip extension includes a radially extending surface interconnecting the side transitional surface and the tip.

7. The airfoil according to claim 1, wherein the side transitional surface extends up to the tip and forms an edge at an intersection therewith.

8. The airfoil according to claim 1, wherein the tip extension has a length defined along the chord less than a length of the chord.

9. The airfoil according to claim 1, wherein the tip extension has a length defined along the chord substantially equal to a length of the chord.

10. The airfoil according to claim 1, wherein the airfoil is part of a compressor rotor blade.

11. The airfoil according to claim 1, wherein the airfoil is part of a turbine rotor blade.

12. The airfoil according to claim 1, wherein at least one of the leading edge and trailing edge is substantially defined as a curve corresponding to an arc of circle, a quadratic equation, or an equation of higher degree than a quadratic equation at the tip.

13. A rotor for an axial compressor of a gas turbine engine, comprising:

a hub adapted to be mounted to a shaft for rotation about a longitudinal axis of the gas turbine engine; and

a plurality of blades connected to the hub and projecting radially therefrom, each of the blades having

an airfoil portion extending radially outward from the hub to a tip, the airfoil having a leading edge, a trailing edge, and a chord defined between the leading edge and the trailing edge, the airfoil defining a suction side surface on one side thereof and a pressure side surface on another and a radial direction being defined from the root to the tip,

a tip extension extending from at least one of the suction side surface and the pressure side surface adjacent the tip and defining a thickness at the tip larger than a true thickness of the airfoil, the true thickness being defined transversely to the chord around a mid point thereof and between the root and the tip extension, and

the tip extension including a side transitional surface substantially defined along a curve extending tangentially from the at least one of the suction side surface and the pressure side surface, the tip extension defining a gradual increase in the thickness over a portion of the airfoil having a radial dimension corresponding to at least 2 times the true thickness.

14. The rotor according to claim 13, wherein the curve along which the side transitional surface is substantially defined corresponds to an arc of circle, a quadratic equation, or an equation of higher degree than a quadratic equation.

15. The rotor according to claim 13, wherein the tip extension is provided on both the suction side surface and the pressure side surface.

16. The rotor according to claim 13, wherein each tip extension includes a tip transitional surface extending between the tip and the side transitional surface, the tip transitional surface being substantially defined along a curve extending tangentially to the side transitional surface and corresponding to an arc of circle, a quadratic equation, or an equation of higher degree than a quadratic equation.

17. The rotor according to claim 13, wherein each tip extension includes a radially extending surface interconnecting the side transitional surface and the tip.

18. The rotor according to claim 13, wherein the side transitional surface extends up to the tip and forms an edge at an intersection therewith.

19. The rotor according to claim 13, wherein the tip extension has a length defined along the chord substantially equal to a length of the chord.

20. A gas turbine engine comprising a compressor section, a combustor and a turbine section, at least one of the compressor section and the turbine section having a rotor, the rotor including:

a hub mounted to a shaft for rotation about a longitudinal axis of the gas turbine engine; and

a plurality of blades connected to the hub and projecting radially therefrom, each of the blades having

an airfoil portion extending radially outward from the hub to a tip, the airfoil having a leading edge, a trailing edge, and a chord defined between the leading edge and the trailing edge, the airfoil defining a suction side surface on one side thereof and a pressure side surface on another, and a radial direction being defined from the root to the tip,

a tip extension extending from at least one of the suction side surface and the pressure side surface adjacent the tip and defining a thickness at the tip larger than a true thickness of the airfoil, the true thickness being defined transversely to the chord around a mid point thereof and between the root and the tip extension, and

the tip extension including a side transitional surface substantially defined along a curve extending tangentially from the at least one of the suction side surface and the pressure side surface, the tip extension defining a gradual increase in the thickness over a portion of the airfoil having a radial dimension corresponding to at least 2 times the true thickness.