Gas turbine engine component having wavy cooling channels with pedestals

1. A gas turbine engine component having an internal cooling channel, the gas turbine engine component comprising:

a plurality of walls having a pair of major surfaces opposed to define an interior chamber;

a cooling channel extending through at least a portion of the interior chamber between the major surfaces of the plurality of walls;

a plurality of ribs extending through the cooling channel to form a plurality of wavy passages having bowed-out sections; and

a plurality of pedestals positioned between adjacent ribs, each pedestal being positioned in a bowed-out section.

2. The gas turbine engine component of claim 1 wherein each wavy passage comprises:

a nominal cross-sectional area between adjacent ribs; and

increased cross-sectional areas at the bowed-out sections;

wherein the pedestals reduce net cross-sectional area between adjacent ribs to below the nominal cross-sectional area.

3. The gas turbine engine component of claim 1 wherein:

successive bowed-out sections increase in length between adjacent ribs; and

pedestals positioned in the successive bowed-out sections increase in size.

4. The gas turbine engine component of claim 3 wherein:

the bowed-out sections are formed by arcuate portions of the ribs being spaced further apart; and

the pedestals are round and have increasing diameters along a streamwise direction.

5. The gas turbine engine component of claim 4 wherein successive bowed-out sections and successive pedestals increase in length and diameter, respectively, in uniform stepped increments.

6. The gas turbine engine component of claim 3 wherein:

the bowed-out sections are formed by straight portions of the ribs being spaced further apart; and

the pedestals are teardrop shaped and have decreasing widths along a streamwise direction.

7. The gas turbine engine component of claim 1 wherein the plurality of ribs further comprises:

straight sections positioned near an end of the cooling channel, the straight sections defining the nominal cross-sectional area for each wavy passage.

8. The gas turbine engine component of claim 7 and further comprising:

a grouping of pedestals located between ends of the plurality of ribs.

9. The gas turbine engine component of claim 1 and further comprising:

restricted sections defined by each wavy passage;

wherein the restricted sections of a first wavy passage are located axially adjacent the bowed-out sections of an adjacent wavy passage.

10. The gas turbine engine component of claim 9 wherein the pedestals are arranged in a staggered pattern within the bowed-out sections.

11. The gas turbine engine component of claim 1 wherein the cooling channel has a uniform width between the major surfaces.

12. The gas turbine engine component of claim 1 wherein the pedestals increase a Mach number and a heat transfer rate for cooling air passing through the wavy passages as compared to a nominal cross-sectional area.

13. The gas turbine engine component of claim 1 wherein multiple pedestals are located in each bowed-out section.

14. A turbine airfoil comprising:

a wall having a leading edge, a trailing edge, a pressure side, a suction side, an outer diameter end and an inner diameter end to define an interior chamber;

a partition extending radially between the inner diameter end and the outer diameter end of the wall within the interior chamber to define a cooling channel having a width; and

a pair of opposing wavy ribs extending radially between the wall and the partition to form a cooling circuit having a length, the cooling circuit comprising:

a constricted portion having a base cross-sectional area; and

an expanded portion having a local cross-sectional area greater than the base cross-sectional area; and

a pedestal positioned in the expanded portion to decrease net local cross-sectional area to below that of the base cross-sectional area.

15. The turbine airfoil of claim 14 wherein:

the pair of opposing wavy ribs form a radially extending series of constricted portions and expanded portions, the constricted portions becoming shorter and the expanded portions becoming longer as the series progresses from the inner diameter end to the outer diameter end; and

further comprising a series of pedestals positioned in the expanded portions, each successive pedestal becoming larger as the series progresses from the inner diameter end to the outer diameter end.

16. The turbine airfoil of claim 15 wherein:

the expanded portions are formed by arcuate portions of the wavy ribs; and

the pedestals are round and are positioned centrally within the expanded portions.

17. The turbine airfoil of claim 14 wherein the ribs further comprise:

straight sections positioned near the inner diameter end of the wall; and

a grouping of pedestals located radially between the outer diameter end of the wall and outer diameter ends of the wavy ribs.

18. The turbine airfoil of claim 14 wherein the pedestals are teardrop shaped.

19. The turbine airfoil of claim 14 wherein multiple pedestals are positioned in the expanded portion to decrease net local cross-sectional area to below that of the base cross-sectional area.

20. A blade outer air seal comprising:

a base extending in a circumferential direction;

a cover extending in the circumferential direction spaced radially from the base to form an internal cavity;

a circumferentially extending series of ribs extending radially between the base and the cover to form a plurality of channels, the ribs being undulated to form a sequence of expansions and contractions; and

an array of pedestals positioned in the expansions.

21. The blade outer air seal of claim 20 :

wherein the plurality of channels have a total cross-sectional area; and

wherein the expansions, pedestals and contractions are configured to reduce the total cross-sectional area as the ribs extend in a circumferential direction.