Impeller shroud with thermal actuator for clearance control in a centrifugal compressor

Patent metadata

Field	Value
Publication number	US-11002284-B2
Application number	US-201916433089-A
Country	US
Kind code	B2
Filing date	Jun 6, 2019
Priority date	May 26, 2016
Publication date	May 11, 2021
Grant date	May 11, 2021

Abstract

A system for controlling the clearance distance between an impeller blade tip of a centrifugal compressor and a radially inner surface of an impeller shroud in a turbine engine. The system comprises a thermal driver coupled between the impeller shroud and engine casing by hinged linkages. The thermal driver includes an annular ring and annular seal which together define thermal driver cavity. Relatively warm or relatively cool air supplied to the thermal driver cavity cause expansion and contraction, respectively, of the annular ring which is translated by linkages into axially forward and aft motion, respectively.

First claim

What is claimed is:

1. A compressor shroud assembly in a turbine engine comprising:
a static compressor casing;
an impeller shroud for encasing a rotatable centrifugal compressor and maintaining a clearance gap between the impeller shroud and the rotatable centrifugal compressor; and
a thermal drive assembly comprising an annular thermal drive ring mounted between said static casing and said impeller shroud and a thermal feed air tube configured to conduct a fluid toward the annular thermal drive ring to expose the annular thermal drive ring to an actuating temperature, wherein the impeller shroud is slidably coupled at a forward end to said casing, said impeller shroud moving relative to the rotatable centrifugal compressor in an axial direction while substantially maintaining a radial alignment when said thermal drive assembly is actuated by exposure of the thermal drive ring to the actuating temperature.

2. The compressor shroud assembly of claim 1 further comprising a drive ring sleeve coupled to said thermal drive ring, said drive ring sleeve and said thermal drive ring at least partly defining a thermal fluid cavity.

3. The compressor shroud assembly of claim 2 wherein said thermal fluid cavity is supplied with the fluid via the thermal feed air tube in fluid communication with said thermal fluid cavity.

4. The compressor shroud assembly of claim 3 wherein said annular thermal drive ring is exposed to the actuating temperature by exposure to one or more of an actuating air, lubricant flow, or fluid flow.

5. The compressor shroud assembly of claim 4 wherein said annular thermal drive ring is exposed to air drawn from the core air of the turbine engine.

6. The compressor shroud assembly of claim 2 wherein said annular thermal drive ring is adapted to axially expand or contract responsive to exposure to the actuating temperature, said annular thermal drive ring contracting axially to effect movement of said shroud in an axially forward direction, said annular thermal drive ring expanding axially to effect movement of said shroud in an axially aft direction.

7. The compressor shroud assembly of claim 1 wherein a slidable coupling between said shroud and said casing is dimensioned to maintain an air boundary during the full range of axial movement of said shroud.

8. The compressor shroud assembly of claim 2 further comprising one or more sensors for measuring the temperature in said thermal fluid cavity, said annular thermal drive ring being exposed to warmer or cooler actuating temperatures in response to the measured temperature in said thermal fluid cavity.

9. The compressor shroud assembly of claim 2 further comprising one or more sensors for measuring the clearance gap between said impeller shroud and the rotatable centrifugal compressor, said annular thermal drive ring being exposed to warmer or cooler actuating temperatures in response to the clearance gap measured by the one or more sensors.

10. The compressor shroud assembly of claim 6 further comprising one or more sensors for measuring the temperature in said thermal fluid cavity, said annular thermal drive ring being exposed to warmer or cooler actuating temperatures in response to the measured temperature in said thermal fluid cavity.

11. A compressor shroud assembly in a turbine engine comprising:
a static compressor casing;
a thermal drive assembly comprising:
an annular thermal drive ring mounted to said casing and adapted to axially expand or contract responsive to exposure to an actuating fluid;
a drive ring sleeve coupled to said annular thermal drive ring, said drive ring sleeve and said annular thermal drive ring at least partly defining a thermal fluid cavity; and
a plurality of thermal feed air tubes, wherein said thermal fluid cavity is fed with an actuating fluid from the plurality of thermal feed air tubes in fluid communication with said thermal fluid cavity; and

an impeller shroud for encasing a rotatable centrifugal compressor and maintaining a clearance gap between the impeller shroud and the rotatable centrifugal compressor, wherein the impeller shroud is mounted at a forward end to said casing and mounted to said annular thermal drive ring, said impeller shroud moving relative to the rotatable centrifugal compressor in an axial direction while substantially maintaining a radial alignment when said thermal drive assembly is actuated.

12. A method of dynamically changing a clearance gap between a rotatable centrifugal compressor and a shroud encasing the rotatable centrifugal compressor, said method comprising:
mounting an annular thermal drive ring to a static casing;
mounting a shroud to the annular thermal drive ring; and
actuating the annular thermal drive ring to thereby move the shroud relative to a rotatable centrifugal compressor.

13. The method of claim 12 further comprising providing an actuating fluid to actuate the annular thermal drive ring.

14. The method of claim 13 wherein said actuating fluid is one of inducer air, exducer air, intermediate stage compressor air, or discharge air from the centrifugal compressor.

15. The method of claim 12 further comprising slidably coupling the forward end of the shroud to the casing, wherein the shroud moves relative to the rotatable centrifugal compressor in an axial direction while substantially maintaining a radial alignment when the annular thermal drive ring is actuated.

16. The method of claim 12 further comprising sensing the fluid temperature in a cavity at least partly defined by said annular thermal drive ring and actuating the annular thermal drive ring in response to the sensed fluid temperature.

17. The method of claim 12 further comprising sensing the clearance gap between the rotatable centrifugal compressor and the shroud and actuating the annular thermal drive ring in response to the sensed clearance gap.

Assignees

• Rolls Royce Corp

Inventors

• Nesteroff Michael
• Acker Jonathan
• Cooper Nate
• Ottow Nathan

Classifications

• F04D29/162 Primary

  of a centrifugal flow wheel · CPC title

• F04D29/622

  Adjusting the clearances between rotary and stationary parts · CPC title

• F01D11/24

  by selectively cooling-heating stator or rotor components · CPC title

• F04D27/0246

  by varying geometry within the pumps, e.g. by adjusting vanes · CPC title

• F04D29/624

  especially adapted for elastic fluid pumps · CPC title