Electronic means for detecting buffered main shaft seal wear or failure in a turbine engine

Patent metadata

Field	Value
Publication number	US-9695709-B2
Application number	US-201213450533-A
Country	US
Kind code	B2
Filing date	Apr 19, 2012
Priority date	Apr 19, 2012
Publication date	Jul 4, 2017
Grant date	Jul 4, 2017

Abstract

In accordance with an embodiment, a gas turbine engine is provided having a bearing chamber leak detection system. The gas turbine engine includes a rotatable shaft, a bearing assembly supporting the rotatable shaft, and a plurality of bearing chamber seals surrounding the rotatable shaft creating an annular bearing chamber enclosing the bearing assembly. One or more walls substantially surrounding the bearing chamber create a plenum between the walls and the bearing chamber, and a pressurized air inlet to the plenum is provided. The pressurized air inlet includes an airflow sensor configured and positioned to sense a flow of pressurized air into the plenum, such that airflow at the sensor is indicative of airflow from the plenum into the bearing chamber via one or more of the plurality of bearing chamber seals.

First claim

What is claimed is:

1. A gas turbine having a bearing chamber leak detection system, the gas turbine comprising:
a rotatable shaft;
a bearing assembly supporting the rotatable shaft;
a plurality of bearing chamber air-oil seals surrounding the bearing assembly creating an annular bearing chamber enclosing the bearing assembly;
one or more walls surrounding the annular bearing chamber creating a plenum that surrounds the annular bearing chamber between the one or more walls and the annular bearing chamber; and
a pressurized air inlet to the plenum, the pressurized air inlet including an airflow sensor configured and positioned to sense a flow of pressurized air into the plenum,
wherein the airflow at the airflow sensor is indicative of airflow from the plenum into the annular bearing chamber via one or more of the plurality of bearing chamber seals;
wherein sensed airflow that is greater than an expected flow is indicative of one or more of the plenum air-oil seals, through which the greater than expected flow is occurring, being damaged or worn.

2. The gas turbine in accordance with claim 1 , wherein the airflow sensor configured and positioned to sense a flow of pressurized air into the plenum is one of a heated film sensor, a vane-type air flow meter, a hot wire meter, and a differential pressure meter.

3. The gas turbine in accordance with claim 1 , further comprising a controller communicatively linked to the airflow sensor.

4. The gas turbine in accordance with claim 3 , wherein the controller communicatively linked to the airflow sensor is configured to calculate an airflow value based on reading the airflow sensor and to detect a leak in one or more of the plurality of bearing chamber seals based on the airflow value.

5. The gas turbine in accordance with claim 4 , wherein the controller is configured to detect a leak in one or more of the plurality of bearing chamber seals based on the airflow value by comparing the airflow value to an expected airflow value to produce a difference value and determining that a leak is present in one or more of the plurality of bearing chamber seals when the difference value exceeds a predetermined variance magnitude.

6. The gas turbine in accordance with claim 4 , wherein the expected airflow value is dependent upon one or more engine operating parameters.

7. The gas turbine in accordance with claim 6 , wherein the one or more engine operating parameters include engine speed, ambient pressure and compressor pressure.

8. The gas turbine in accordance with claim 4 , wherein the controller includes a user interface output for providing an alert to an operator when it is determined that a leak is present in one or more of the plurality of bearing chamber seals.

9. The gas turbine in accordance with claim 4 , wherein the controller further includes an output interface to a memory device for logging leak event data.

10. The gas turbine in accordance with claim 1 , wherein the flow of pressurized air into the plenum is provided from a buffer chamber.

11. The gas turbine in accordance with claim 1 , wherein the flow of pressurized air into the plenum is provided via one or more bleed holes from a compressor stage of the engine.

12. A method of detecting a leak in one or more bearing chamber seals protecting a bearing assembly within a bearing chamber in a gas turbine engine, the method comprising:
providing a flow of pressurized air through a pressurized air inlet into a plenum that surrounds the bearing chamber and bearing chamber seals, wherein the flow of pressurized air is provided against the one or more bearing chamber air-oil seals from outside of the bearing chamber;
positioning an airflow sensor in the pressurized air inlet;
measuring a flow of the pressurized air into the bearing chamber using the airflow sensor; and
determining that a leak in at least one of the bearing chamber seals in the plenum is present if the measured flow of pressurized air exceeds an expected flow of pressurized air;
wherein sensed airflow that is greater than an expected flow is indicative of one or more of the plenum air-oil seals, through which the leak is occurring, being damaged or worn.

13. The method of detecting a leak in accordance with claim 12 , wherein providing a flow of pressurized air against the one or more bearing chamber seals from outside of the bearing chamber comprises introducing pressurized air into the plenum formed of one or more walls that are surrounding the bearing chamber.

14. The method of detecting a leak in accordance with claim 13 , wherein introducing pressurized air into the plenum surrounding the bearing chamber comprises directing air from one or more bleed holes in a compression stage of the engine to the plenum.

15. The method of detecting a leak in accordance with claim 12 , wherein measuring a flow of the pressurized air into the bearing chamber comprises measuring a flow of the pressurized air through the plenum.

16. The method of detecting a leak in accordance with claim 12 , wherein determining that a leak in at least one of the bearing chamber seals is present if the measured flow of pressurized air exceeds an expected flow of pressurized air comprises deriving the expected flow of pressurized air based at least on engine speed.

17. The method of detecting a leak in accordance with claim 12 , wherein the measured flow of pressurized air is determined to exceed the expected flow of pressurized air if the measured flow is greater than the expected flow by more than a predetermined variance.

18. The method of detecting a leak in accordance with claim 12 , wherein determining that a leak in at least one of the bearing chamber seals is present further comprises determining that there is a defect in an air system circuit and/or air system component.

19. The method of detecting a leak in accordance with claim 18 , wherein the defect in an air system circuit and/or air system component includes a defect in one of an active clearance system, a buffer cooler system, and another air system.

20. A controller for detecting a bearing seal leak in a gas turbine engine having a bearing assembly within a bearing chamber bordered by a plurality of bearing chamber air-oil seals, wherein the plurality of bearing chamber seals are pressurized from outside of the bearing chamber via pressurized air through a pressurized air inlet in a plenum that surrounds the bearing chamber and bearing chamber seals, the controller being configured to execute steps including:
positioning an airflow sensor in the pressurized air inlet;
measuring a flow of pressurized air into the bearing chamber via at least one of the plurality of bearing chamber seals using the airflow sensor;
providing an expected flow of pressurized air, the expected flow being a function of at least engine speed;
comparing the measured flow to the expected flow to derive a difference value; and
determining that a leak in at least one of the plurality of bearing chamber seals in the plenum is present when the difference value exceeds a predetermined variance value;
wherein sensed airflow that exceeds a predetermined variance value is indicative of one or more of the plenum air-oil seals, through which the leak is occurring, is damaged or worn.

Assignees

• Parnin Francis
• Amador Armando
• United Technologies Corp

Inventors

• Parnin Francis
• Amador Armando

Classifications

• G01M3/2869

  for seals not incorporated in a pipe joint · CPC title

• G01M15/14

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

• F01D25/18 Primary

  Lubricating arrangements (of machines or engines in general F01M) · CPC title