Method of manufacturing BOAS enhanced heat transfer surface

1. A method of manufacturing a seal, comprising:

providing a seal arc segment defining first and second seal supports at circumferential ends, the seal arc segment further defining radially inner and outer sides, the radially outer side including radially-extending sidewalls and a radially inner surface joining the radially-extending sidewalls, the radially-extending sidewalls and the radially inner surface defining a pocket; and

machining the radially inner surface to have a higher surface roughness than the sidewalls, wherein the seal arc segment comprises ceramic, and the machining is done in a bisque state.

2. The method as recited in claim 1 , comprising:

machining circumferentially-extending channels in the radially inner surface.

3. The method as recited in claim 1 , comprising:

machining a channel of a first width at a first section of the radially inner surface, and machining a channels wider than the first width at a second section of the radially inner surface, wherein the first section is axially spaced from the second section.

4. The method as recited in claim 1 , the method comprising:

suspending the seal arc segment from a carriage defining first and second circumferentially spaced support members, the first support member supporting the first seal support in a first ramped interface and the second support member supporting the second seal support in a second ramped interface.

5. The method as recited in claim 4 , comprising:

machining circumferentially-extending channels in the radially inner surface.

6. The method as recited in claim 1 , the radially-extending sidewalls including four contiguous radially-extending sidewalls, the first seal support extending from a first of the radially-extending sidewalls, and the second seal support extending from a second of the radially extending sidewalls circumferentially opposite the first of the radially-extending sidewalls.

7. A method of manufacturing a seal, comprising:

providing a seal arc segment defining first and second seal supports at circumferential ends, the seal arc segmant further defining radially inner and outer sides, the radially outer side including radially extending sidewalls and a radially inner surface joining the radially-extending sidewalls, the radially-extending sidewalls and radially inner surface defining a pocket;

machining the radially inner surface to have a higher surface roughness than the sidewalls;

machining a channel of a first depth at a first section of the radially inner surface; and

machining a channel deeper than the first depth at a second section of the radially inner surface, wherein the first section is axially spaced from the second section.

8. The method as recited in claim 7 , wherein the seal arc segment comprises ceramic, and the machining is done in a bisque state.

9. The method as recited in claim 7 , the radially-extending sidewalls including four contiguous radially-extending sidewalls, the first seal support extending from a first of the radially-extending sidewalls, and the second seal support extending from a second of the radially extending sidewalls circumferentially opposite the first of the radially-extending sidewalls.

10. A method of manufacturing a seal, comprising:

providing a seal arc segment defining first and second seal supports at circumferential ends, the seal arc segment further defining radially inner and outer sides, the radially outer side including radially-extending sidewalls and a radially inner surface joining the radially-extending sidewalls, the radially-extending sidewalls and the radially inner surface defining a pocket;

machining the radially inner surface to have a higher surface roughness than the sidewalls;

machining channels spaced apart a first distance at a first section of the surface; and

machining channels spaced apart a second distance at a second section of the radially inner surface, the first section axially spaced from the section, and the first distance different from the second distance.

11. The method as recited in claim 10 , wherein the seal arc segment comprises ceramic, and the machining is done in a bisque state.

12. A method of manufacturing a seal, comprising:

providing a seal arc segment defining first and second seal supports at circumferential ends, the seal arc segmant further defining radially inner and outer sides, the radially outer side including radially extending sidewalls and a radially inner surface joining the radially-extending sidewalls, the radially-extending sidewalls and radially inner surface defining a pocket;

machining the radially inner surface to have a higher surface roughness than the sidewalls;

machining a first surface roughness at a first section of the radially inner surface; and

machining a second surface roughness at a second section of the radially inner surface, wherein the first section is axially spaced from the second section, the first surface roughness is different from the second surface roughness, and the first surface roughness and the second surface roughness are greater than the surface roughness of the sidewalls.

13. The method as recited in claim 12 , wherein the seal arc segment comprises ceramic, and the machining is done in a bisque state.

14. A method of manufacturing a seal, comprising:

providing a seal arc segment defining first and second seal supports at circumferential ends, the seal arc segment further defining radially inner and outer sides, the radially outer side including radially-extending sidewalls and a radially inner surface joining the radially-extending sidewalls, the radially-extending sidewalls and the radially inner surface defining a pocket;

machining the radially inner surface to have a higher surface roughness than the sidewalls;

providing a carriage defining first and second circumferentially spaced support members radially outward of the seal arc segment with respect to the seal arc segment; and

suspending the seal arc segment from a carriage, the first support member supporting the first seal support in a first ramped interface and the second support member supporting the second seal support in a second ramped interface, the radially-extending sidewalls including four contiguous radially-extending sidewalls, the first seal support extending from a first of the radially-extending sidewalls, and the second seal support extending from a second of the radially extending sidewalls circumferentially opposite the first of the radially-extending sidewalls.

15. The method as recited in claim 14 , wherein the seal arc segment comprises ceramic.

16. The method as recited in claim 15 , wherein the machining is done in a bisque state.

17. The method as recited in claim 14 , comprising:

machining circumferentially-extending channels in the radially inner surface.

18. The method as recited in claim 14 , comprising:

machining a channel of a first depth at a first section of the radially inner surface, and

machining a channels deeper than the first depth at a second section of the radially inner

surface, wherein the first section is axially spaced from the second section.

19. A method of manufacturing a seal, comprising:

providing a seal arc segment defining first and second seal supports at circumferential ends, the seal arc segment further defining radially inner and outer sides, the radially outer side including radially-extending sidewalls and a radially inner surface joining the radially-extending sidewalls, the radially-extending sidewalls and the radially inner surface defining a pocket;

machining the radially inner surface to have a higher surface roughness than the sidewalls;

providing a carriage defining first and second circumferentially spaced support members radially outward of the seal arc segment with respect to the seal arc segment;

suspending the seal arc segment from a carriage, the first support member supporting the first seal support in a first ramped interface and the second support member supporting the second seal support in a second ramped interface;

machining channels spaced apart a first distance at a first section of the surface; and

machining channels spaced apart a second distance at a second section of the radially inner surface, the first section axially spaced from the section, and the first distance different from the second distance.

20. The method as recited in claim 19 , wherein the seal arc segment comprises ceramic, and the machining is done in a bisque state.