Turbine airfoil trailing edge cooling slots

• US 9,017,026 B2
• Filed: 04/03/2012
• Issued: 04/28/2015
• Est. Priority Date: 04/03/2012
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Bergholz, Robert Frederick Jr., Durstock, Daniel Lee
• Primary Examiner(s): EDGAR, RICHARD A
• Application Number:
  US13/438,296
• Publication Number:
  US 20130259705A1
• Time in Patent Office: 1,120 Days
• Field of Search: None
• US Class Current: 416/97.R
• CPC Class Codes: F01D 5/186 Film cooling F01D5/187 takes precedence
• CPC Class Codes: F05D 2240/122 related to the trailing edge of a stator vane
• CPC Class Codes: F05D 2240/304 related to the trailing edge of a rotor blade
• CPC Class Codes: F05D 2260/202 by film cooling
• CPC Class Codes: F05D 2260/22141 using fins or ribs
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A turbine airfoil includes pressure and suction sidewalls extending along a span from a base to a tip. Spanwise spaced apart trailing edge cooling holes in the pressure sidewall end at corresponding spanwise spaced apart trailing edge cooling slots extending chordally substantially to the trailing edge. Each cooling hole includes a plug extending downstream through at least a portion of a spanwise diverging section leading into the slot. The plug may be spanwise centered in the hole and may include a plug dome rising up from a plug base extending along a suction sidewall surface of the suction sidewall. The cooling hole may further include an inlet leading to a metering section with a constant area and constant width flow cross section upstream of spanwise diverging section. Lands may be disposed between the trailing edge cooling slots forming slot floors between lands.

Claims

1. A gas turbine engine turbine airfoil comprising:

widthwise spaced apart pressure and suction sidewalls extending outwardly along a span from an airfoil base to an airfoil tip;

the pressure and suction sidewalls extending chordwise between opposite leading and trailing edges;

a spanwise row of spanwise spaced apart trailing edge cooling holes encased in the airfoil between the pressure and suction sidewalls and ending at corresponding spanwise spaced apart trailing edge cooling slots extending chordally substantially to the trailing edge;

each of the cooling holes including a spanwise diverging section leading into the trailing edge cooling slot; and

a plug disposed in each of the cooling holes and the plug extending downstream through at least a portion of the diverging section, the plug further comprising a plug dome rising up from a plug base of the plug and the plug base extending along a suction sidewall surface of the suction sidewall, the plug being spanwise centered in the hole and including widthwise and spanwise rounded upstream and downstream dome ends.

2. The airfoil as claimed in claim 1 further comprising:

a flow cross section between the plug and the cooling hole,

the flow cross section having a cross sectional flow area equal to a difference between a cross sectional hole area of the cooling hole and a cross sectional plug area of the plug, and

the cross sectional flow area in the diverging section increasing in a downstream direction.

3. The airfoil as claimed in claim 2 further comprising:

the flow cross section between the plug and the cooling hole having two relatively wide rounded lobes at distal ends of a relatively narrow rectangular middle section,

a height of the flow cross section increasing through an entire length of the diverging section,

the lobes extending between pressure and suction sidewall surfaces of the pressure and suction sidewalls respectively in the diverging section, and

the lobes having a maximum width equal to a width of the diverging section between the pressure and suction sidewall surfaces in the diverging section.

4. The airfoil as claimed in claim 3 further comprising the lobes being substantially wider than the middle section.

5. The airfoil as claimed in claim 2 further comprising lands disposed between spanwise adjacent ones of the trailing edge cooling slots and slot floors in the trailing edge cooling slots between the lands.

6. The airfoil as claimed in claim 5 further comprising the lands being coplanar or flush with an external surface of the pressure sidewall around each of the cooling slots.

7. The airfoil as claimed in claim 6 further comprising:

a deck extending chordwise or downstream from the diverging sections of the cooling holes past the slot floors substantially to the trailing edge,

the deck extending spanwise or radially outwardly from a bottommost one of the slot floors to a topmost one of the slot floors, and

upper and lower deck sidewalls extending from the deck to the external surface of the pressure sidewall and spanwise bounding the deck.

8. The airfoil as claimed in claim 1 further comprising the plugs further extending through at least a portion of the trailing edge cooling slot.

9. A gas turbine engine turbine airfoil comprising:

widthwise spaced apart pressure and suction sidewalls extending outwardly along a span from an airfoil base to an airfoil tip;

the pressure and suction sidewalls extending chordwise between opposite leading and trailing edges;

a spanwise row of spanwise spaced apart trailing edge cooling holes encased in the airfoil between the pressure and suction sidewalls and ending at corresponding spanwise spaced apart trailing edge cooling slots extending chordally substantially to the trailing edge;

each of the cooling holes including in downstream serial cooling flow relationship, an inlet, a metering section with a constant area and constant width flow cross section, and a spanwise diverging section leading into the trailing edge cooling slot; and

a plug disposed in each of the cooling holes and the plug extending downstream through at least a portion of the diverging section, the plug further comprising a plug dome rising up from a plug base of the plug and the plug base extending along a suction sidewall surface of the suction sidewall, the plug being spanwise centered in the hole and including widthwise and spanwise rounded upstream and downstream dome ends.

10. The airfoil as claimed in claim 9 further comprising:

a flow cross section between the plug and the cooling hole,

the flow cross section having a cross sectional flow area equal to a difference between a cross sectional hole area of the cooling hole and a cross sectional plug area of the plug, and

the cross sectional flow area in the diverging section increasing in a downstream direction.

11. The airfoil as claimed in claim 10 further comprising:

the flow cross section between the plug and the cooling hole having two relatively wide rounded lobes at distal ends of a relatively narrow rectangular middle section,

a height of the flow cross section increasing through an entire length of the diverging section,

the lobes extending between pressure and suction sidewall surfaces of the pressure and suction sidewalls respectively in the diverging section, and

the lobes having a maximum width equal to a width of the diverging section between the pressure and suction sidewall surfaces in the diverging section.

12. The airfoil as claimed in claim 11 further comprising the lobes being substantially wider than the middle section.

13. The airfoil as claimed in claim 12 further comprising lands disposed between spanwise adjacent ones of the trailing edge cooling slots and slot floors in the trailing edge cooling slots between the lands.

14. The airfoil as claimed in claim 13 further comprising the lands being coplanar or flush with an external surface of the pressure sidewall around each of the cooling slots.

15. The airfoil as claimed in claim 13 further comprising:

a deck extending chordwise or downstream from the diverging sections of the cooling holes past the slot floors substantially to the trailing edge,

the deck extending spanwise or radially outwardly from a bottommost one of the slot floors to a topmost one of the slot floors, and

upper and lower deck sidewalls extending from the deck to the external surface of the pressure sidewall and spanwise bounding the deck.

16. The airfoil as claimed in claim 9 further comprising:

the cooling hole having a spanwise height substantially greater than a hole width through the cooling hole,

pressure and suction sidewall surfaces of the pressure and suction sidewalls respectively in the hole, and

the pressure sidewall surface being planar through the entire metering and diverging sections.

17. The airfoil as claimed in claim 16 further comprising:

a flow cross section between the plug and the cooling hole,

the flow cross section having a cross sectional flow area equal to a difference between a cross sectional hole area of the cooling hole and a cross sectional plug area of the plug, and

the cross sectional flow area in the diverging section increasing in a downstream direction.

18. The airfoil as claimed in claim 17 further comprising:

the flow cross section between the plug and the cooling hole having two relatively wide rounded lobes at distal ends of a relatively narrow rectangular middle section,

a height of the flow cross section increasing through an entire length of the diverging section,

the lobes extending between pressure and suction sidewall surfaces of the pressure and suction sidewalls respectively in the diverging section, and

the lobes having a maximum width equal to a width of the diverging section between the pressure and suction sidewall surfaces in the diverging section.

19. The airfoil as claimed in claim 18 further comprising the lobes being substantially wider than the middle section.

20. The airfoil as claimed in claim 19 further comprising lands disposed between spanwise adjacent ones of the trailing edge cooling slots and slot floors in the trailing edge cooling slots between the lands.

21. The airfoil as claimed in claim 20 further comprising the lands being coplanar or flush with an external surface of the pressure sidewall around each of the cooling slots.

22. The airfoil as claimed in claim 20 further comprising:

a deck extending chordwise or downstream from the diverging sections of the cooling holes past the slot floors substantially to the trailing edge,

the deck extending spanwise or radially outwardly from a bottommost one of the slot floors to a topmost one of the slot floors, and

upper and lower deck sidewalls extending from the deck to the external surface of the pressure sidewall and spanwise bounding the deck.

23. The airfoil as claimed in claim 22 further comprising the width being constant through the metering section of the hole.

24. The airfoil as claimed in claim 20 further comprising:

the lobes having corner radii,

fillets in slot corners between the lands and the slot floors, and

the fillets having fillet radii substantially the same size as the corner radii of the lobes.

25. The airfoil as claimed in claim 24 further comprising the diverging section and the trailing edge cooling slot diverging at different first and second diverging angles respectively.

26. The airfoil as claimed in claim 25 further comprising the plugs further extending through at least a portion of the trailing edge cooling slot.

27. The airfoil as claimed in claim 9 further comprising the metering and diverging sections having a hole height to hole width ratio of the spanwise height and the hole width in a range of about 2:

1 to 10;

1.