Axially-split radial turbines and methods for the manufacture thereof

1. A method for manufacturing an axially-split radial turbine, the method comprising:

fabricating a forward bladed ring from a plurality of bladed pieces each including at least one forward blade segment, fabricating a forward bladed ring comprising:

casting the plurality of forward bladed pieces;

arranging the plurality of forward bladed pieces in a ring formation; and

metallurgically consolidating the plurality of forward bladed pieces included in the ring formation to yield the forward bladed ring;

joining the forward bladed ring to a forward disk to produce a forward turbine rotor;

fabricating an aft turbine rotor; and

disposing the forward turbine rotor and the aft turbine rotor in an axially-abutting, rotationally-fixed relationship to produce the axially-split radial turbine;

wherein the step of metallurgically consolidating comprises:

loading the ring formation into a thermal growth constraint tool; and

heating the ring formation to a predetermined temperature at which the outward radial growth of the ring formation is constrained by the thermal growth constraint tool to urge the forward bladed pieces together and promote the inter-bonding thereof.

2. A method according to claim 1 wherein the ring formation comprises first and second composite tooling contact surfaces, and wherein the step of loading comprises positioning first and second thermal growth constraint rings around the first and second composite tooling contact surfaces, respectively.

3. A method according to claim 2 further comprising the step of disposing at least one crush ring between the ring formation and the thermal growth constraint tool.

4. A method for manufacturing an axially-split radial turbine, the method comprising:

fabricating a forward turbine rotor comprising a forward hub section from which a plurality of forward blade segments extends, fabricating a forward turbine rotor comprising:

producing a forward bladed ring embodying, at least in substantial part, the plurality of forward blade segments; and

producing a forward disk embodying, at least in substantial part, the forward hub section;

fabricating an aft turbine rotor comprising an aft hub section from which a plurality of aft blade segments extends;

creating an inner disk cavity within at least one of the forward hub section and the aft hub section; and

assembling the forward turbine rotor and the aft turbine rotor to produce the axially-split radial turbine.

5. A method according to claim 4 wherein the step of producing a forward bladed ring comprises:

casting a plurality of forward bladed pieces including a plurality of blade cooling passages; and

metallurgically consolidating the plurality of forward bladed pieces into the forward bladed ring.

6. The method of claim 4 further comprising forming a plurality of blade cooling passages in the plurality of forward blade segments and fluidly coupled to the inner disk cavity when the axially-split radial turbine is assembled.

7. The method of claim 4 wherein the step of creating an inner disk cavity comprises removing material from at least one of the aft face of the forward turbine rotor and the forward face of the aft turbine rotor prior to disposing the forward turbine rotor and the aft turbine rotor in an axially-abutting, rotationally-fixed relationship.

8. A method for manufacturing an axially-split radial turbine, the method comprising:

fabricating a forward bladed ring from a plurality of bladed pieces each including at least one forward blade segment, the plurality of forward bladed pieces cast to include a plurality of blade cooling passages;

joining the forward bladed ring to a forward disk to produce a forward turbine rotor;

fabricating an aft turbine rotor; and

disposing the forward turbine rotor and the aft turbine rotor in an axially-abutting, rotationally-fixed relationship to produce the axially-split radial turbine.

9. A method according to claim 8 further comprising the step of forming an inner disk cavity within the axially-split radial turbine in fluid communication with the plurality of blade cooling passages.

10. A method according to claim 9 wherein the step of forming an inner disk cavity comprises removing material from at least one of the aft face of the forward turbine rotor and the forward face of the aft turbine rotor prior to disposing the forward turbine rotor and the aft turbine rotor in an axially-abutting, rotationally-fixed relationship.

11. A method according to claim 9 further comprising the step of forming at least one hub cooling passage extending in the body of the axially-split radial turbine.

12. A method according to claim 11 wherein the at least one hub cooling passage extends from an inner circumferential surface of the axially-split radial turbine to the inner disk cavity.

13. A method for manufacturing an axially-split radial turbine, the method comprising:

joining a forward bladed ring to a forward disk to produce a forward turbine rotor;

fabricating an aft turbine rotor, comprising:

fabricating an aft bladed ring from a plurality of aft bladed pieces each including at least one aft blade segment; and

joining the aft bladed ring to an aft disk to produce the aft turbine rotor; and

disposing the forward turbine rotor and the aft turbine rotor in an axially-abutting, rotationally-fixed relationship to produce the axially-split radial turbine.

14. A method according to claim 13 further comprising fabricating the forward bladed ring from a plurality of bladed pieces each including at least one forward blade segment.

15. A method according to claim 14 wherein the step of fabricating the forward bladed ring comprises:

casting the plurality of forward bladed pieces;

arranging the plurality of forward bladed pieces in a ring formation; and

metallurgically consolidating the plurality of forward bladed pieces included in the ring formation to yield the forward bladed ring.

16. A method according to claim 15 wherein the step of casting comprises casting each of the plurality of forward bladed pieces from a single crystal superalloy.

17. A method according to claim 16 further comprising the step of forging the forward disk from a non-single crystal superalloy.

18. A method according to claim 13 wherein the step of fabricating the aft bladed ring comprises casting the plurality of aft bladed pieces to include a plurality of blade cooling passages.