Turbine disk

1. A turbine rotor, comprising:

a disk rotationally disposed about a central axis, the disk including

a bore disposed about the central axis, the bore having

a fore surface including a fore web transition portion, a fore ramp portion radially inward of the fore web transition portion and a fore base transition portion radially inward of the fore ramp portion,

an aft surface including an aft web transition portion, an aft ramp portion radially inward of the aft web transition portion and an aft base transition portion radially inward of the aft ramp portion and

a base portion;

a rim having a first rim portion and a second rim portion, the second rim portion disposed radially inward of the first rim portion;

a first blade post disposed proximate the first rim portion;

a first tab disposed proximate the second rim portion, the first tab positioned radially inward of the first blade post and having a first axial profile;

a slot disposed circumferentially adjacent the first tab, the slot having a roof portion that defines a roof angle extending radially outward with respect to the central axis, the roof angle ranging from 35 degrees to 45 degrees,

wherein the first axial profile of the first tab provides a forward facing surface that includes a blade post transition portion, disposed circumferentially adjacent a radially inward most branch of a plurality of branches spaced radially between a base and a tip of the first blade post and at a radial distance from the central axis equal to that of the radially inward most branch, a slope portion radially inward of the blade post transition portion and a face portion radially inward of the slope portion, the blade post transition portion defining a radius of curvature that transitions a first portion of the first blade post to the slope portion; and

a web disposed radially between the bore and the rim, the web having a fore surface and an aft surface,

wherein the base portion of the bore includes a spool engagement surface, a first arm extending in an aft direction and a second arm extending in a fore direction and

wherein the base portion further includes a radially extending first transition portion connecting an aft end of the spool engagement surface to a radially inward portion of the first arm and a radially extending second transition portion connecting a fore end of the spool engagement surface to a radially inward portion of the second arm.

2. The turbine rotor of claim 1 , wherein the radially extending first transition portion includes a first face portion defining a surface normal pointing substantially in an aft axial direction.

3. The turbine rotor of claim 2 , wherein the radially extending second transition portion includes a second face portion defining a surface normal pointing substantially in a fore axial direction.

4. The turbine rotor of claim 3 , further comprising an aft transition region connecting the aft surface of the web to the aft surface of the bore.

5. The turbine rotor of claim 4 , further comprising a fore transition region connecting the fore surface of the web to the fore surface of the bore.

6. The turbine rotor of claim 5 , further comprising a substantially linear aft ramp portion extending from the aft transition region to a radially outward portion of the first arm.

7. The turbine rotor of claim 6 , further comprising a substantially linear fore ramp portion extending from the fore transition region to a radially outward portion of the second arm.

8. The turbine rotor of claim 7 , further comprising a circumferential face portion connecting the substantially linear aft ramp portion to the radially outward portion of the first arm.

9. The turbine rotor of claim 8 , wherein the circumferential face portion defines a surface normal pointing substantially in the aft axial direction.

10. The turbine rotor of claim 9 , wherein the aft transition region is located within a range of about 14 inches to about 15 inches in a radial direction from the central axis.

11. The turbine rotor of claim 10 , wherein the fore transition region is located within a range of about 14 inches to about 15 inches in a radial direction from the central axis.

12. The turbine rotor of claim 11 , further comprising an axial length between the first face portion and the second face portion and wherein the axial length is within a range of 3.6 inches to 3.7 inches.

13. A turbine rotor, comprising:

a disk rotationally disposed about a central axis, the disk including

a bore disposed about the central axis, the bore having

a fore surface including a fore web transition portion, a fore ramp portion radially inward of the fore web transition portion and having a substantially linear portion and a fore base transition portion radially inward of the fore ramp portion,

an aft surface including an aft web transition portion, an aft ramp portion radially inward of the aft web transition portion and having a substantially linear portion and an aft base transition portion radially inward of the aft ramp portion and a base portion;

a rim having a first rim portion and a second rim portion, the second rim portion disposed radially inward of the first rim portion;

a first blade post disposed proximate the first rim portion;

a first tab disposed proximate the second rim portion, the first tab positioned radially inward of the first blade post and having a first axial profile;

a slot disposed circumferentially adjacent the first tab, the slot having a roof portion that defines a roof angle extending radially outward with respect to the central axis, the roof angle ranging from 35 degrees to 45 degrees,

wherein the first axial profile of the first tab provides a forward facing surface that includes a blade post transition portion, disposed circumferentially adjacent a radially inward most branch of a plurality of branches spaced radially between a base and a tip of the first blade post and at a radial distance from the central axis equal to that of the radially inward most branch, a slope portion radially inward of the blade post transition portion and a face portion radially inward of the slope portion, the blade post transition portion defining a radius of curvature that transitions a first portion of the first blade post to the slope portion; and

a web disposed radially between the bore and the rim, the web having a fore surface and an aft surface,

wherein the base portion of the bore includes a spool engagement surface, a first arm extending in an aft direction and a second arm extending in a fore direction and

wherein the base portion further includes a radially extending first transition portion connecting an aft end of the spool engagement surface to a radially inward portion of the first arm and a radially extending second transition portion connecting a fore end of the spool engagement surface to a radially inward portion of the second arm.

14. The turbine rotor of claim 13 , wherein the radially extending first transition portion includes a first face portion defining a surface normal pointing substantially in an aft axial direction.

15. The turbine rotor of claim 14 , wherein the radially extending second transition portion includes a second face portion defining a surface normal pointing substantially in a fore axial direction.

16. The turbine rotor of claim 15 , further comprising an aft transition region connecting the aft surface of the web to the aft surface of the bore.

17. The turbine rotor of claim 16 , further comprising a fore transition region connecting the fore surface of the web to the fore surface of the bore.

18. The turbine rotor of claim 17 , further comprising an axial length between the first face portion and the second face portion and wherein the axial length is within a range of 3.6 inches to 3.7 inches.

19. A turbine rotor, comprising:

a disk rotationally disposed about a central axis, the disk including

a bore disposed about the central axis, the bore having

a fore surface including a fore web transition portion, a fore ramp portion radially inward of the fore web transition portion and a fore base transition portion radially inward of the fore ramp portion,

an aft surface including an aft web transition portion, an aft ramp portion radially inward of the aft web transition portion and an aft base transition portion radially inward of the aft ramp portion and

a base portion;

a rim having a first rim portion and a second rim portion, the second rim portion disposed radially inward of the first rim portion;

a first blade post disposed proximate the first rim portion;

a first tab disposed proximate the second rim portion, the first tab positioned radially inward of the first blade post and having a first axial profile;

a slot disposed circumferentially adjacent the first tab, the slot having a roof portion that defines a roof angle extending radially outward with respect to the central axis, the roof angle ranging from 35 degrees to 45 degrees,

wherein the first axial profile of the first tab provides a forward facing surface that includes a blade post transition portion, disposed circumferentially adjacent a radially inward most branch of a plurality of branches spaced radially between a base and a tip of the first blade post and at a radial distance from the central axis equal to that of the radially inward most branch, a slope portion radially inward of the blade post transition portion and a face portion radially inward of the slope portion, the blade post transition portion defining a radius of curvature that transitions a first portion of the first blade post to the slope portion; and

a web disposed radially between the bore and the rim, the web having a fore surface and an aft surface,

wherein the base portion of the bore includes a first arm extending in an aft direction and a second arm extending in a fore direction and

wherein the base portion further includes a radially extending first transition portion connecting an aft end of the base portion to a radially inward portion of the first arm and a radially extending second transition portion connecting a fore end of the base portion to a radially inward portion of the second arm.

20. The turbine rotor of claim 19 , further comprising an axial length between the radially extending first transition portion and the radially extending second transition portion and wherein the axial length is within a range of 3.6 inches to 3.7 inches.