Segregated impeller shroud for clearance control in a centrifugal compressor

Patent metadata

Field	Value
Publication number	US-10935044-B2
Application number	US-201916529404-A
Country	US
Kind code	B2
Filing date	Aug 1, 2019
Priority date	May 26, 2016
Publication date	Mar 2, 2021
Grant date	Mar 2, 2021

Abstract

A system for controlling the clearance distance between an impeller blade tip of a centrifugal compressor and a radially inner surface of a segregated impeller shroud in a turbine engine. The system comprises a driving mechanism coupled to a portion of a segregated impeller shroud. The driving mechanism comprises a driving arm and threaded axial member configured to translate motion of an actuator ring into axially forward and aft motion of the portion of the segregated impeller shroud.

First claim

What is claimed is:

1. A compressor shroud assembly comprising:
a static compressor casing;
an actuator carried by said casing, said actuator comprising a driving member extending along a radius of the axis of rotation of a rotatable centrifugal impeller and being rotatable about said axis; and
an impeller shroud for encasing the rotatable centrifugal impeller, the impeller shroud coupled at a forward end to said casing by a slidable coupling that maintains an air boundary during the full range of axial movement of said impeller shroud, said shroud being threadably coupled to said driving member so that rotation of said driving member about the axis of rotation effects translation of at least a portion of said shroud relative to the rotatable centrifugal impeller.

2. The compressor shroud assembly of claim 1 wherein the translation of at least a portion of said shroud relative to the rotatable centrifugal impeller is in an axial direction while maintaining a radial alignment of said portion of said shroud.

3. The compressor shroud assembly of claim 1 wherein said actuator further comprises a driving mechanism coupled to said driving member to rotate said driving member about the axis of rotation when said actuator is actuated.

4. The compressor shroud assembly of claim 1 wherein said threaded coupling between said driving member and said shroud comprises driving threads which rotate with said driving member while maintaining an axial alignment, and driven threads which translate axially with said portion of said shroud.

5. The compressor shroud assembly of claim 4 wherein said actuator comprises two or more driving members spaced around the axis of rotation of said driving members.

6. The compressor shroud assembly of claim 5 further comprising an actuating ring coupled to each of said driving members and to said driving mechanism.

7. The compressor shroud assembly of claim 1 further comprising one or more sensors for measuring the clearance gap between said axially translatable portion of said shroud and the rotatable centrifugal impeller, said actuator being actuated in response to the clearance gap measured by the one or more sensors.

8. The compressor shroud assembly of claim 1 further comprising one or more sensors for measuring discharge pressure of the rotatable centrifugal impeller, said actuator being actuated in response to the measured pressure.

9. A compressor section in a gas turbine engine, said compressor section comprising:
a static casing;
a rotatable centrifugal impeller; and
a compressor shroud assembly comprising:
an actuator carried by said casing, said actuator comprising a driving member extending along a radius of the axis of rotation of the rotatable centrifugal impeller and being rotatable about the axis; and
an impeller shroud for encasing said rotatable centrifugal impeller, said shroud comprising a static inducer portion statically coupled to said casing and an axially translatable exducer portion threadably coupled to said inducer portion and statically coupled to said driving member, the threaded coupling between said inducer portion and said exducer portion comprising static threads which maintain an axial alignment and moveable threads which rotate and axially translate with said driving member and said exducer portion to effect translation of said exducer portion relative to the rotatable centrifugal impeller in an axial direction.

10. The compressor section of claim 9 wherein said exducer portion comprises a first exducer portion threadably coupled to a second exducer portion, each of said exducer portions being independently axially translatable.

11. The compressor section of claim 10 wherein said first exducer portion is coupled to a first actuator and said second exducer portion is coupled to a second actuator.

12. The compressor section of claim 11 wherein said first actuator comprises said driving member and a driving mechanism coupled to said driving member to rotate said driving member about the axis of rotation when said actuator is actuated.

13. The compressor section of claim 11 wherein said second actuator comprises said driving member and a driving mechanism coupled to said driving member to rotate said driving member about the axis of rotation when said actuator is actuated.

14. The compressor section of claim 12 wherein said actuator comprises two or more driving members spaced around the axis of rotation of said driving members.

15. The compressor section of claim 14 further comprising an actuating ring coupled to each of said driving members and to said driving mechanism.

16. A compressor shroud assembly comprising:
a static compressor casing;
an impeller shroud for encasing a rotatable centrifugal impeller, said shroud comprising:
an inducer portion mounted to said casing;
a first exducer portion coupled to said inducer portion; and
a second exducer portion threadably coupled to said first exducer portion,

wherein each of said first and second exducer portions is independently translatable relative to the rotatable centrifugal impeller in an axial direction while maintaining a radial alignment; and
an actuator carried by said casing, wherein said actuator is operable to rotate about the axis of the centrifugal impeller to effect translation of one or both of said first exducer portion and said second exducer portion.

17. The compressor assembly of claim 16 wherein said actuator comprises a driving member extending along a radius of the axis of rotation of the rotatable centrifugal impeller and being rotatable about the axis.

18. The compressor assembly of claim 16 further comprising a threaded coupling between said inducer portion and said first exducer portion wherein relative rotation about the axis of the centrifugal impeller between said inducer portion and said first exducer portion effects axial translation of said first exducer portion.

19. The compressor assembly of claim 16 further comprising a threaded coupling between said first exducer portion and said actuator, wherein relative rotation about the axis of the centrifugal impeller between said first exducer portion and said actuator effects axial translation of said first exducer portion.

Assignees

• Rolls Royce Corp

Inventors

• Ottow Nathan
• Acker Johnathan
• Cooper Nate
• Whitlock Mark
• Nesteroff Michael

Classifications

• F04D29/162

  of a centrifugal flow wheel · CPC title

• F05D2250/281

  threaded · CPC title

• F01D11/22

  by mechanically actuating the stator or rotor components, e.g. moving shroud sections relative to the rotor · CPC title

• F04D29/4206 Primary

  especially adapted for elastic fluid pumps · CPC title

• F05D2270/3013

  Outlet pressure · CPC title