Method and Apparatus for Geometric Rotor Stacking and Balancing

• US 20090234481A1
• Filed: 05/22/2009
• Published: 09/17/2009
• Est. Priority Date: 09/26/2006
• Status: Active Grant

• Current Assignee: Axiam, Inc.
• Original Assignee: Axiam, Inc.
• Inventors: Lee, Robert M., Parsons, Robert E.
• Granted Patent: US 7,877,223 B2
• Time in Patent Office: Days
• US Class Current: 700/98
• CPC Class Codes: F01D 5/027 Arrangements for balancing for balancing rotating bodies in general F16F15/32; for compensating unbalance G01M1/36
• CPC Class Codes: G06F 2111/10 Numerical modelling
• CPC Class Codes: G06F 30/20 Design optimisation, verification or simulation optimisation, verification or simulation of circuit designs G06F30/30

Abstract

A computer method or corresponding system for optimally balancing a rotor assembly. The computer system defines a theoretical centerline based on a mathematical model of the rotor assembly. For each disc or component of the rotor assembly, the invention system calculates rotor blade or bolt and washer distribution, based on calculated centerline deviations and angular locations of the discs and effective weights of rotor blade or bolt-and-washer sets. The rotor blade or bolt-and-washer distribution provides locations for placement of the rotor blades or bolts-and-washers so as to offset the centerline deviations and thus correct imbalance of the rotor assembly.

Claims

1. A method for correcting imbalance of a rotor assembly for a turbine engine, comprising the computer implemented steps of:

defining a centerline of a rotor assembly based on a mathematical model of the rotor assembly, the rotor assembly being formed of discs and components, each disc for carrying a respective set of rotor blades or bolts-and-washers;

for each disc and component of the rotor assembly, calculating a centerline deviation and an angular location of the disc or component; and

determining rotor blade or bolt-and-washer distribution throughout the rotor assembly based on (a) the calculated centerline deviations and the angular locations of the discs and components of the rotor assembly and (b) respective weight of each rotor blade or bolt-and-washer, the rotor blade or bolt-and-washer distribution providing rotor blade or bolt-and-washer locations which offset the centerline deviations by weight and result in a balanced rotor assembly.

2. The method of claim 1, wherein the step of determining rotor blade or bolt-and-washer distribution includes weighing a set of rotor blades or bolts-and-washers of the turbine engine by pan weight or moment weight.

3. The method of claim 1, further comprising marking each rotor blade or bolt-and-washer with an identifying number and the blade location about a respective disc.

4. The method of claim 1, wherein the step of determining rotor blade or bolt-and-washer distribution further includes for each disc, computing the locations of respective rotor blades or bolts-and-washers in order to offset the centerline deviation of the disc.

5. The method of claim 1, further including displaying an indicator of the determined rotor blade or bolt-and-washer distribution to a user.

6. The method of claim 5, wherein the indicator of the determined rotor blade or bolt-and-washer distribution is displayed in numerical format.

7. The method of claim 5, wherein the indicator of the rotor blade or bolt-and-washer distribution is displayed in graphical format.

8. The method of claim 5, further including assembling the rotor blades or bolts-and-washers on the respective disc based on the displayed information.

9. The method of claim 8, further including verifying the rotor assembly resulting from the assembly, against the mathematical model.

10. The method of claim 1, wherein the step of calculating includes determining measurement characteristics in any combination of:

roundness, flatness, concentricity, concentricity angle, runout, runout angle, perpendicularity, perpendicularity angle, perpendicular plane deviation, centerline deviation, centerline deviation angle, biplane deviation and biplane deviation angle.

11. The method of claim 1, wherein the rotor assembly is assembled into any of a low-pressure turbine, an intermediate-pressure turbine, a high-pressure turbine, a low-pressure compressor, an intermediate-pressure compressor, or a high-pressure compressor.

12. The method of claim 11, wherein the step of defining a centerline of the rotor assembly includes determining a centerline generated between bearing journals.

13. A computer system for correcting imbalance of a rotor assembly for a turbine engine, comprising:

a definition module configured to define a centerline of a rotor assembly based on a mathematical model of the rotor assembly, the rotor assembly being formed of discs and components, each disc for carrying a respective set of rotor blades or bolts-and-washers;

a calculation module configured to calculate a centerline deviation and an angular location of the disc or component for each disc and component of the rotor assembly; and

a determination module configured to determine rotor blade or bolt-and-washer distribution throughout the rotor assembly based on (a) the calculated centerline deviations and the angular locations of the discs and components of the rotor assembly and (b) respective weight of each rotor blade or bolt-and-washer, the rotor blade or bolt-and-washer distribution providing rotor blade or bolt-and-washer locations which offset the centerline deviations and result in an optimally balanced rotor assembly.

14. The computer system of claim 13 wherein the determination module weighs a set of rotor blades or bolts-and-washers of the turbine engine by pan weight or moment weight.

15. The computer system of claim 13, further comprising a marking module configured to mark each rotor blade or bolt-and-washer with an identifying number and the location about a respective disc.

16. The computer system of claim 13 wherein the determination module computes the locations of respective rotor blades or bolts-and-washers in order to offset the centerline deviation of the disc for each disc.

17. The computer system of claim 13 wherein a display module is configured to display an indicator of the determined rotor blade or bolt-and-washer distribution to a user.

18. The computer system of claim 17, wherein the indicator of the determined rotor blade or bolt-and-washer distribution is displayed in numerical format.

19. The computer system of claim 17, wherein the indicator of the rotor blade or bolt-and-washer distribution is displayed in graphical format.

20. The computer system of claim 17, further comprising an assembly module configured to assemble the rotor blades or bolts-and-washers on the respective disc based on the displayed information.

21. The computer system of claim 20, further including a verification module configured to verify the rotor assembly resulting from the assembly, against the mathematical model.

22. The computer system of claim 13, wherein the calculation module is further configured to determine measurement characteristics in any combination of:

roundness, flatness, concentricity, concentricity angle, runout, runout angle, perpendicularity, perpendicularity angle, perpendicular plane deviation, center-line deviation, centerline deviation angle, biplane deviation and biplane deviation angle.

23. The computer system of claim 13, wherein the rotor assembly is assembled into any of a low-pressure turbine, an intermediate-pressure turbine, a high-pressure turbine, a low-pressure compressor, and intermediate-pressure compressor, or a high-pressure compressor.

24. The computer system of claim 13, wherein a definition module is further configured to determine a centerline generated between bearing journals of the rotor assembly.

25. The computer system of claim 13, wherein the rotor assembly is assembled into a low shaft, intermediate shaft, or high shaft, respectively to meet target vibration threshold/criteria.