Situ blade mounted tip gap measurement for turbines

Patent metadata

Field	Value
Publication number	US-9513117-B2
Application number	US-201314043913-A
Country	US
Kind code	B2
Filing date	Oct 2, 2013
Priority date	Oct 2, 2013
Publication date	Dec 6, 2016
Grant date	Dec 6, 2016

Abstract

Turbine blade tip clearance is measured in a fully assembled turbine casing by mounting a contact or non-contact displacement probe on a turbine blade that generates data indicative of probe distance from the turbine casing that circumferentially surrounds the blade. Variations in probe distance data are recorded as the blade circumferentially sweeps the turbine casing when the turbine is operated in turning gear mode. Blade rotational position data are collected by a rotational position sensor. A data processing system correlates the distance and rotational position data with localized blade tip gap at angular positions about the turbine casing circumference. An optical camera inspection system may be coupled to a turbine blade to obtain visual inspection information within the turbine casing. This method and apparatus provide an accurate and cost effective solution for accessing turbine casing deformation impact on blade tip clearance and rotor/casing alignment.

First claim

What is claimed is:

1. A method for measuring gas turbine blade tip and turbine ring segment radial clearance gap, comprising:
providing a gas turbine including: a turbine casing having an inner circumferential ring segment that fully circumscribes a rotatable rotor oriented within the casing, the rotor having a row of turbine blades radially aligned with the ring segment, each blade having an airfoil that defines an airfoil outer surface and a radially outwardly projecting tip in opposed, spaced relationship with the circumscribing ring segment, each respective blade tip defining a radial clearance gap between itself and the circumscribing ring segment at a plurality of rotational angular positions of the blade and rotor;
coupling on an airfoil surface of a first one of said blades at least one non-contact displacement sensor that generates a displacement data set of distance between the displacement sensor and the ring segment;
coupling on the airfoil surface of the same first one of said blades a rotor rotational position sensor that generates a rotational position data set indicative of rotational angular orientation of said first blade relative to the circumscribing ring segment;
rotating the rotor so that the blade tip of said first blade sweeps at least a portion of the circumscribing ring segment, while generating the displacement data set with the displacement sensor and a rotational position data set with the rotor rotational position sensor at plural angular positions along the blade tip sweep;
acquiring the displacement and rotational position data sets with a data acquisition system that is coupled to the displacement and rotational position sensors; and
correlating blade tip and circumscribing ring segment radial clearance gap relative to angular rotational position of said first blade, with the displacement and rotational data sets, at plural angular positions along the blade tip sweep, in a data analyzer system that is coupled to the data acquisition system.

2. The method of claim 1 further comprising: directly coupling an optical camera having a field of view to one of a plurality of operational turbine blade airfoils; and capturing images within the turbine with the camera during rotor rotation.

3. The method of claim 1 , the non-contact displacement sensor comprising a visible light or infra-red probe having at least one photonic energy transmitter and a corresponding receiver.

4. The method of claim 1 , the non-contact displacement sensor comprising a pair of tandem visible light or infra-red proximity sensors respectively oriented proximal the blade tip leading and trailing edges.

5. The method of claim 1 , the non-contact displacement sensor comprising an ultrasonic proximity sensor.

6. The method of claim 1 , the rotor rotational position sensor comprising a tilt sensor, or a triangulated GPS position sensor.

7. The method of claim 1 , further comprising coupling the data acquisition and data analyzer systems by wireless communication, cable or by physical transfer of a non-volatile data storage device.

8. The method of claim 1 , further comprising coupling one or more of the displacement sensor, the rotational position sensor or the data acquisition system to the turbine blade airfoil with a magnet.

9. A method for measuring gas turbine blade tip and turbine ring segment radial clearance gap, comprising:
providing a gas turbine including: a turbine casing having an access port and an inner circumferential ring segment that fully circumscribes a rotatable rotor oriented within the casing, the rotor having a row of turbine blades radially aligned with the ring segment, each blade having an airfoil that defines an airfoil outer surface and a radially outwardly projecting tip in opposed, spaced relationship with the circumscribing ring segment, each respective blade tip defining a gap between itself and the circumscribing ring segment at a plurality of rotational angular positions of the blade and rotor;
inserting into the turbine casing through the access port, and coupling on an airfoil surface of a first one of said blades at least one non-contact displacement sensor that generates a displacement data set of distance between the displacement sensor and the ring segment;
inserting into the turbine casing through the access port, and coupling on the airfoil surface of the same first one of said blades a rotor rotational position sensor that generates a rotational position data set indicative of rotational angular orientation of said first blade relative to the circumscribing ring segment;
rotating the rotor so that the blade tip of said first blade sweeps at least a portion of the circumscribing ring segment, while generating the displacement data set with the displacement sensor and a rotational position data set with the rotor rotational position sensor at plural angular positions along the blade tip sweep;
acquiring the displacement and rotational position data sets with a data acquisition system that is coupled to the displacement and rotational position sensors; and
correlating blade tip and circumscribing ring segment radial clearance gap relative to angular rotational position of said first blade, with the displacement and rotational data sets, at plural angular positions along the blade tip sweep, in a data analyzer system that is coupled to the data acquisition system.

10. The method of claim 9 , further comprising: directly coupling an optical camera having a field of view to one of a plurality of turbine blade airfoils; and capturing images within the turbine, including the circumscribing turbine casing, with the camera during rotor rotation.

11. The method of claim 9 , further comprising coupling the data acquisition system to one or more turbine blades.

12. The method of claim 11 , further comprising coupling the displacement sensor, rotational position sensor and data acquisition system to a common substrate that is in turn coupled to the same airfoil surface.

13. The method of claim 12 , the rotational position sensor comprising a tilt sensor, and further comprising coupling the common substrate to the same airfoil surface with a magnet.

14. The method of claim 9 , the displacement sensor comprising any one of an infra-red or a visible light probe having at least one photonic energy transmitter and a corresponding receiver, or an ultrasonic proximity sensor.

15. The method of claim 9 , further comprising inserting into the turbine casing through the access port and directly coupling an optical camera having a field of view to one of a plurality of turbine blade airfoils, and capturing images within the turbine, including the circumscribing turbine casing, with the camera during rotor rotation.

16. The method of claim 9 , the non-contact displacement sensor comprising a pair of tandem non-contact displacement sensors respectively oriented proximal leading and trailing edges of the blade tip of said first one of said blades.

17. The method of claim 9 , the rotational position sensor comprising any one of a tilt sensor, or a triangulated GPS position sensor.

18. The method of claim 9 , the data acquisition and data analyzer systems communicatively coupled by wireless communication, cable or by physical transfer of a non-volatile data storage device.

19. A method for measuring gas turbine blade tip and turbine ring segment radial clearance gap, comprising:
providing a gas turbine including: a turbine casing having an access port and an inner circumferential ring segment that fully circumscribes a rotatable

Assignees

• Ruhge Forrest R
• Hatcher Jr Clifford
• Siemens Energy Inc

Inventors

• Ruhge Forrest R
• Hatcher Jr Clifford

Classifications

• G01N21/8803

  Visual inspection (measuring projectors G01B9/08) · CPC title

• G01B21/16 Primary

  for measuring distance of clearance between spaced objects · CPC title

• F05D2270/821

  Displacement measuring means, e.g. inductive · CPC title

• G01B11/14

  for measuring distance or clearance between spaced objects or spaced apertures (G01B11/26 takes precedence; rangefinders G01C3/00) · CPC title

• G01M15/02

  Details or accessories of testing apparatus · CPC title