Gas turbine engine having a metallic test sample and a method of determining the service life of a gas turbine engine component using a metallic test sample

Patent metadata

Field	Value
Publication number	US-11053859-B2
Application number	US-201916298611-A
Country	US
Kind code	B2
Filing date	Mar 11, 2019
Priority date	Mar 20, 2018
Publication date	Jul 6, 2021
Grant date	Jul 6, 2021

Abstract

A method of determining the service life of a gas turbine engine component comprises providing, within a gas turbine engine, a component having an air washed surface, the component comprises a metal, wherein the air washed surface receives a supply of cooling air from a chamber within the gas turbine engine. The method also comprises mounting a metallic test sample within the chamber so as to be located in the supply of air which is delivered to the air washed surface. The metallic test sample is constructed of the same metal as the component. The method further comprises removing the metallic test sample and determining the degree of corrosion of the metallic test sample.

First claim

The invention claimed is:

1. A gas turbine engine, comprising:
a component having a gas path facing surface and an air cooled surface, wherein the air cooled surface is arranged to receive a supply of cooling air, the gas path facing surface is arranged to receive a supply of hot gas, the component comprises a metal;
a chamber in fluid communication with the air cooled surface, in operation the chamber is arranged to supply air to the air cooled surface or the chamber is arranged to receive air which has been supplied to the air cooled surface;
a plurality of metallic test samples mounted within the chamber so as to be located in the air which is to be delivered to the air cooled surface or to be located in the air delivered by the air cooled surface, wherein each test sample of the plurality of metallic test samples is connected to an adjacent metallic test sample by a frangible connection and is constructed of the metal of the component or a similar metal to the component.

2. The gas turbine engine as claimed in claim 1 , wherein the plurality of metallic test samples are located at one circumferential position around a principal axis of the gas turbine engine.

3. The gas turbine engine as claimed in claim 1 , wherein the plurality of metallic test samples are located at a plurality of circumferential positions around a principal axis of the gas turbine engine.

4. The gas turbine engine as claimed in claim 3 , wherein several metallic samples of the plurality of metallic test samples are located at each of the circumferential positions around the principal axis of the gas turbine engine.

5. The gas turbine engine as claimed in claim 1 , wherein each metallic test sample of plurality of metallic test samples is removably secured on a boroscope plug.

6. The gas turbine engine as claimed in claim 1 , wherein the component comprises one of a nickel alloy, a titanium alloy and a steel alloy.

7. The gas turbine engine as claimed in claim 1 , wherein the component comprises one of a turbine blade, a turbine vane, a turbine shroud, a turbine disc, a turbine blisk, a compressor blade, a compressor vane, a compressor disc, a compressor drum, a compressor blisk and a compressor blum.

8. A method of determining a service life of a component of a gas turbine engine, comprising:
providing, within the gas turbine engine, the component having a gas path facing surface and an air cooled surface, wherein the air cooled surface is arranged to receive a supply of cooling air, the gas path facing surface is arranged to receive a supply of hot gas, the component comprises a metal;
supplying the cooling air to the air cooled surface;
supplying the hot gas to the gas path facing surface;
supplying the cooling air from a chamber within the gas turbine engine to the air cooled surface or supplying the cooling air from the air cooled surface to the chamber within the gas turbine engine;
mounting a plurality of metallic test samples within the chamber so as to be located in the supply of the cooling air which is delivered to the air cooled surface or to be located in the supply of the cooling air which is delivered by the air cooled surface, wherein each test sample of the plurality of the metallic test samples is connected to an adjacent metallic test sample by a frangible connection and constructed of the metal of the component or a similar metal to the component;
removing the plurality of metallic test samples and determining a degree of corrosion of the plurality of metallic test samples.

9. The method as claimed in claim 8 , further comprising:
removing the plurality of metallic test samples after a first period of operation;
determining a degree of corrosion of the plurality of metallic test samples after the first period of operation;
determining whether the component is suitable for a second period of operation based on the the degree of corrosion of the plurality of metallic test samples after the first period of operation; and,
returning the gas turbine engine to service without replacing the component.

10. The method as claimed in claim 9 , wherein determining whether the component is suitable for a second period of operation comprises comparing the degree of corrosion of the plurality of metallic test samples after the first period of operation with a database of corrosion damage for exposure time versus exposure temperature versus salt level exposure for the metal.

11. The method as claimed in claim 9 , further comprising:
removing at least one of the plurality of metallic test samples and retaining some of the plurality of metallic test samples within the gas turbine engine for the second period of operation.

12. The method as claimed in claim 11 , further comprising:
removing at least one of the some of the plurality of metallic test samples after the second period of operation;
determining the degree of corrosion of the some of the metallic test sample after the second period of operation;
determining whether the component is suitable for a third period of operation based on the degree of corrosion after the second period of operation;
retaining some of the some of the plurality of metallic test samples within the gas turbine engine for the third period of operation and, returning the gas turbine engine to service without replacing the component.

13. The method as claimed in claim 12 , wherein determining whether the component is suitable for a third period of operation comprises comparing the degree of corrosion after the second period of operation with a database of corrosion damage for exposure time versus exposure temperature versus salt level exposure for the metal.

14. The method as claimed in claim 9 , wherein the method comprises returning the gas turbine engine to service without replacing the component for a second period of operation which is less than the first period of operation or which is more than the first period of operation.

15. The method as claimed in claim 12 , wherein the method comprises returning the gas turbine engine to service without replacing the component for a third period of operation which is less than the second period of operation or which is more than the second period of operation.

16. The method as claimed in claim 8 , wherein determining the degree of corrosion comprises determining an amount of metal loss from the plurality of metallic test samples by cross-sectioning a metallic test sample of the plurality of metallic test samples and measuring one or more of a thickness of an oxide layer from an outer surface of a metallic test sample of the plurality of metallic test samples, a corrosion pit depth from an inner surface of the oxide layer and a depth of internal corrosion of one of the plurality of metallic test samples from a bottom of a corrosion pit.

17. The method as claimed in claim 8 , further comprising: mounting the plurality of metallic test samples within the chamber so as to be located in the supply of the cooling air which is delivered to the cooling air cooled surface or to be located in the supply of the cooling air which is delivered by the air cooled surface, wherein the metallic test sample is constructed the metal as the component: mounting a second plurality of metallic test samples within the chamber so as to be located in the supply of the cooling air which is delivered to the cooling air cooled surface or to be located in the supply of the cooling air which is delivered by the air cooled surface, wherein the second plurality of metallic test samples is a similar metal to the component;
removing the plurality o

Assignees

• Rolls Royce Plc

Inventors

• Gibson Grant J

Classifications

• G01M15/02

  Details or accessories of testing apparatus · CPC title

• G01M15/14

  Testing gas-turbine engines or jet-propulsion engines · CPC title

• F02C3/04

  having a turbine driving a compressor (power transmission arrangements F02C7/36; control of working fluid flow F02C9/16) · CPC title

• F01D21/003 Primary

  Arrangements for testing or measuring (for measuring vibrations G01H) · CPC title

• F01D21/00

  Shutting-down of machines or engines, e.g. in emergency; Regulating, controlling, or safety means not otherwise provided for · CPC title