Microturbine power generating system

• US 6,307,278 B1
• Filed: 09/12/2000
• Issued: 10/23/2001
• Est. Priority Date: 12/20/1997
• Status: Expired due to Fees

• Current Assignee: Honeywell Power Systems Inc (Honeywell International Inc.)
• Original Assignee: Honeywell Power Systems Inc (Honeywell International Inc.)
• Inventors: Doshi, Ramesh, Emerson, Terence, Nims, Robert A., Denk, Joseph
• Primary Examiner(s): Ponomarenko, Nicholas
• Application Number:
  US09/659,627
• Time in Patent Office: 406 Days
• Field of Search: 290/52, 310/156, 310/51, 310/75.D, 415/173.3, 60/395.11
• US Class Current: 290/52
• CPC Class Codes: F01D 15/10 Adaptations for driving, or combinations with, electric generators
• CPC Class Codes: F02C 3/05 the compressor and the turbine being of the radial flow type
• CPC Class Codes: F02C 7/08 Heating air supply before combustion, e.g. by exhaust gases
• CPC Class Codes: F05D 2240/60 Shafts
• CPC Class Codes: F05D 2250/311 the axes being in line
• CPC Class Codes: F05D 2250/82 Micromachines
• CPC Class Codes: F05D 2250/84 Nanomachines
• CPC Class Codes: H02K 7/1823 structurally associated with turbines or similar engines

Abstract

A rotating group for a microturbine power generation system includes an electrical generator rotor, a turbine and a compressor intermediate the generator and the turbine. The turbine, compressor and electrical generator rotor are secured together by a tieshaft. The tieshaft is prestressed such that faces of the turbine, electrical generator rotor and compressor maintain contact during high-speed, high-temperature operation of the system.

Claims

1. A rotating group for a microturbine power generating system, comprising:

a turbine wheel receiving expanding gas, the expanding gas causing the turbine wheel to rotate about an axis;

a rotor having at least one rotor surface and a rotor bore concentric with the axis, at least a portion of said rotor being magnetic, wherein said at least one rotor surface is adapted for rotation within at least one foil journal bearing;

a single tieshaft having a diameter of less than about one-half inch, the tieshaft being concentric with the axis and extending through the rotor bore, the tieshaft having a yield strength and being preloaded in tension to a predetermined percentage of said yield strength; and

means for maintaining the tension in the tieshaft and securing said rotor and said turbine wheel to rotate in unison with the tieshaft.

2. A rotating group for a microturbine power generating system according to claim 1, further comprising:

an impeller wheel having an impeller bore concentric with the axis, the tieshaft further extending through the impeller bore; and

means for securing said impeller wheel to rotate in unison with the tieshaft.

3. The rotating group of claim 2, wherein the rotor has inner and outer sleeves, the outer sleeve being non-magnetic and surrounding the magnetic portion of the rotor, the inner sleeve surrounding the rotor bore.

4. The rotating group of claim 2, wherein the turbine wheel is boreless.

5. A rotating group for a microturbine power generating system according to claim 4, wherein the tieshaft is secured to the turbine wheel by an inertia weld.

6. A rotating group for a microturbine power generating system according to claim 1, further comprising:

at least one thrust disk extending concentrically from the rotor, adapted for rotation between at least two foil thrust bearings.

7. A rotating group for a microturbine power generating system according to claim 6, wherein the at least one rotor surface adapted for rotation within at least one foil journal bearing comprises first and second rotor surfaces located on opposite sides of the magnetic portion of the rotor and adapted for rotation within first and second foil journal bearings.

8. A rotating group for a microturbine power generating system according to claim 6, wherein the at least one thrust disk comprises one thrust disk located between the rotor and the turbine wheel.

9. A rotating group for a microturbine power generating system according to claim 3, wherein the impeller wheel is positioned between the rotor and the turbine wheel, and the at least one rotor surface adapted for rotation within at least one foil journal bearing comprises first and second rotor surfaces located on opposite sides of the magnetic portion of the rotor and adapted for rotation within first and second foil journal bearings, further comprising:

a thrust disk extending concentrically from the rotor between the magnetic portion of the rotor and the impeller wheel, adapted for rotation between two foil thrust bearings.

10. A rotating group for a microturbine power generating system according to claim 9, wherein the turbine wheel is boreless.

11. A rotating group for a microturbine power generating system according to claim 1, wherein the predetermined percentage of said yield strength is about 90%.

12. A rotating group for a microturbine power generating system according to claim 10, wherein the predetermined percentage of said yield strength is about 90%.

13. A rotating group for a microturbine power generating system, comprising:

a turbine wheel, a compressor wheel, a rotor, and a single tieshaft, each of said turbine wheel, compressor wheel, rotor, and single tieshaft having a common axis and being secured in fixed relation relative to each other, wherein;

said rotor includes (a) a rotor bore concentric with the axis, (b) a magnetic portion comprising a two-pole permanent magnet, and (c) at least one rotor surface adapted for rotation within at least one foil journal bearing; and

said single tieshaft extends through the rotor bore.

14. A rotating group for a microturbine power generating system according to claim 13, wherein said compressor wheel has a compressor wheel bore concentric with the axis and said single tieshaft extends through the compressor wheel bore.

15. A rotating group for a microturbine power generating system according to claim 14, wherein the at least one rotor surface adapted for rotation within at least one foil journal bearing comprises first and second rotor surfaces located on opposite sides of the magnetic portion of the rotor and adapted for rotation within first and second foil journal bearings.

16. A rotating group for a microturbine power generating system according to claim 15, further comprising a thrust disk extending concentrically from the rotor between the magnetic portion of the rotor and the compressor wheel and adapted for rotation between two foil thrust bearings.

17. A rotating group for a microturbine power generating system according to claim 13, wherein the rotor has an outer containment sleeve made of a non-magnetic material and surrounding the magnetic portion of the rotor.

18. A rotating group for a microturbine power generating system according to claim 16, wherein the rotor has an outer containment sleeve made of a non-magnetic material and surrounding the magnetic portion of the rotor.

19. A rotating group for a microturbine power generating system according to claim 13, wherein the rotor has inner and outer sleeves, the outer sleeve being non-magnetic and surrounding the magnetic portion of the rotor, the inner sleeve surrounding the rotor bore.

20. A rotating group for a microturbine power generating system according to claim 16, wherein the rotor has inner and outer sleeves, the outer sleeve being non-magnetic and surrounding the magnetic portion of the rotor, the inner sleeve surrounding the rotor bore.

21. A rotating group for a microturbine power generating system according to claim 17, wherein the two-pole permanent magnet includes magnets made of a rare earth material selected from the group that includes samarium cobalt.

22. A rotating group for a microturbine power generating system according to claim 18, wherein the two-pole permanent magnet includes magnets made of a rare earth material selected from the group that includes samarium cobalt.

23. A rotating group for a microturbine power generating system according to claim 19, wherein the two-pole permanent magnet includes magnets made of a rare earth material selected from the group that includes samarium cobalt.

24. A rotating group for a microturbine power generating system according to claim 20, wherein the two-pole permanent magnet includes magnets made of a rare earth material selected from the group that includes samarium cobalt.

25. A rotating group for a microturbine power generating system, comprising:

a turbine wheel, a compressor wheel, a rotor, and a single tieshaft, each of said turbine wheel, compressor wheel, rotor, and single tieshaft having a common axis and being secured in fixed relation relative to each other, wherein;

said rotor includes (a) a rotor bore concentric with the axis, and (b) a magnetic portion comprising a two-pole permanent magnet; and

said single tieshaft extends through the rotor bore.

26. A rotating group for a microturbine power generating system according to claim 25, wherein said compressor wheel has a compressor wheel bore concentric with the axis and said single tieshaft extends through the compressor wheel bore.

27. A rotating group for a microturbine power generating system according to claim 25, wherein the rotor has an outer containment sleeve made of a non-magnetic material and surrounding the magnetic portion of the rotor.

28. A rotating group for a microturbine power generating system according to claim 27, wherein the two-pole permanent magnet includes magnets made of a rare earth material selected from the group that includes samarium cobalt.

29. A rotating group for a microturbine power generating system according to claim 25, wherein the rotor has inner and outer sleeves, the outer sleeve being non-magnetic and surrounding the magnetic portion of the rotor, the inner sleeve surrounding the rotor bore.

30. A rotating group for a microturbine power generating system according to claim 29, wherein the two-pole permanent magnet includes magnets made of a rare earth material selected from the group that includes samarium cobalt.

31. A rotating group for a microturbine power generating system, comprising:

a turbine wheel receiving expanding gas, the expanding gas causing the turbine wheel to rotate about an axis;

an impeller wheel having an impeller bore concentric with the axis;

a rotor having at least one rotor surface and a rotor bore concentric with the axis;

a single tieshaft being concentric with the axis and extending through the impeller bore and the rotor bore; and

means for maintaining tension in the tieshaft and securing said impeller wheel, said rotor and said turbine wheel to rotate in unison with the tieshaft,

wherein said impeller wheel has a front side, a back side, and impeller vanes, the impeller vanes being disposed on said impeller wheel front side, wherein said turbine wheel has a front side, a back side, and turbine vanes, the turbine vanes being disposed on said turbine wheel front side, and wherein said impeller wheel back side faces said turbine wheel back side.

32. A rotating group for a microturbine power generating system according to claim 31, further comprising:

at least one thrust disk extending concentrically from the rotor, adapted for rotation between at least two foil thrust bearings.

33. A rotating group for a microturbine power generating system according to claim 32, wherein said at least one rotor surface comprises first and second rotor surfaces located on opposite sides of a magnetic portion of the rotor, said first and second rotor surfaces being adapted for rotation within first and second foil journal bearings.

34. A rotating group for a microturbine power generating system according to claim 32, wherein the at least one thrust disk comprises one thrust disk located between the rotor and the turbine wheel.

35. A rotating group for a microturbine power generating system according to claim 31, wherein the impeller wheel is positioned between the rotor and the turbine wheel, wherein the at least one rotor surface comprises first and second rotor surfaces located on opposite sides of a magnetic portion of the rotor, said first and second rotor surfaces being adapted for rotation within first and second foil journal bearings, further comprising:

a thrust disk extending concentrically from the rotor between the magnetic portion of the rotor and the impeller wheel, said thrust disk being adapted for rotation between two foil thrust bearings.