Airfoil pedestaled trailing edge region cooling configuration

• US 4,407,632 A
• Filed: 06/26/1981
• Issued: 10/04/1983
• Est. Priority Date: 06/26/1981
• Status: Expired due to Term

• Current Assignee: United Technologies Corporation (Rtx Corporation)
• Original Assignee: United Technologies Corporation (Rtx Corporation)
• Inventors: Liang, George P.
• Primary Examiner(s): Coe, Philip R.
• Assistant Examiner(s): Stinson, Frankie L.
• Application Number:
  US06/277,480
• Time in Patent Office: 830 Days
• Field of Search: 416/97 R, 416/96 A, 415/115
• US Class Current: 416/97.00R
• CPC Class Codes: F01D 5/187 Convection cooling
• CPC Class Codes: F05D 2260/2212 by creating turbulence

Abstract

The trailing edge region of an airfoil includes a slot formed between the pressure and suction side walls with an array of pedestals extending across the slot, wherein selected pairs of pedestals are connected by a barrier wall adjacent either the pressure or suction side of the slot. The barrier walls extend inwardly toward the opposite side wall only partway across the slot to trip the thermal boundary layer of the cooling air flowing in the slot. These barrier walls alternate, in the downstream direction, between the pressure side and the suction side of the slot such that cooling air flowing downstream must move back and forth between the pressure and suction side walls in order to pass over these walls. Simultaneously, as the cooling air travels downstream, it snakes around the pedestals. The result is that the cooling air flows through the slot along a plurality of spiral or vortex-like flow paths resulting in improved heat transfer.

Claims

1. An airfoil having a suction side wall and a pressure side wall defining a forward portion of said airfoil and a trailing edge region of said airfoil, said trailing edge region including a trailing edge, said suction side wall and said pressure side wall being spaced apart defining a cooling air cavity within said forward portion and a slot of width W in said trailing edge region, said slot being in communication with said cavity for receiving cooling air from said cavity, said airfoil including means defining outlet passageways through said trailing edge in communication with said slot for discharging cooling air from said slot through said trailing edge;

a plurality of spaced apart pedestals extending across said slot from said pressure side wall to said suction side wall, said pedestals being arranged in an array wherein they are located at each vortex formed by two criss-crossing sets of parallel lines, the distance between adjacent parallel lines in both sets being equivalent to define a grid of congruent diamonds, said sets of parallel lines being angled relative to each other such that a line connecting a first pair of opposing vertices of each diamond is substantially parallel to the spanwise direction of the airfoil;

a plurality of suction side fences joining each pair of adjacent pedestals along each of the lines of one of said two sets of criss-crossing parallel lines, wherein each suction side fence is a wall of length G and of height A extending inwardly from said suction side wall, said height A being less than the slot width W; and

a plurality of pressure side fences joining each pair of adjacent pedestals along each of the lines of said other of said two sets of criss-crossing parallel lines, wherein each pressure side fence is a wall of height B extending inwardly from said pressure side wall, said height B being less than the slot width W.

2. The airfoil according to claim 1 wherein the height A is greater than or equal to the thickness of the thermal boundary layer along the suction side of said slot, and the height B is greater than or equal to the thickness of the thermal boundary layer along the pressure side of said slot.

3. The airfoil according to claim 2 wherein the height A equals the height B and neither height is greater than half the slot width W.

4. The airfoil according to claims 1, 2 or 3 wherein said pedestals are cylinders of diameters D, said pedestal density is about 50%, and the distance G is approximately equal to the diameter D.

5. The airfoil according to claim 2 wherein the pedestal density is between about 35% and 50%.

6. The airfoil according to claim 5 wherein said grid of congruent diamonds is a grid of congruent squares.

7. The airfoil according to claim 6 wherein said pedestals are cylinders of diameter D, and the distance G is approximately equal to the diameter D.

8. The airfoil according to claims 1, 2 or 5 wherein said pedestals are cylinders of diameter D.