JP2013185593A - System and method for improved stator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system including a rotary machine.SOLUTION: A rotary machine includes a rotor having a plurality of blades and a segmented stator having a plurality of stator segments arranged circumferentially about the plurality of blades. Each adjacent pair of first and second segments of the plurality of stator segments includes a recess extending circumferentially across an intermediate joint between the first and second segments. Furthermore, each recess includes at least one eccentricity control insert configured to mitigate eccentricity of an inner circumference of the segmented stator due to thermal expansion or thermal contraction of the segmented stator.

Description

  The subject matter disclosed herein relates to casings for use with various types of rotating systems such as compressors and gas turbines.

  Rotating systems such as compressors and turbines generally include a rotor section that rotates about an axis during system operation and a stator section that remains substantially stationary during system operation (e.g., casing, shroud, etc.). ). For example, in a compressor, the rotor portion includes blades disposed around the shaft. During operation of the compressor, the shaft can rotate, rotating the attached blades in a stationary casing (stator) surrounding the rotor. However, the temperature present in the compressor can be high (eg, greater than 1000 ° C.) and a portion of the compressor rotor and / or casing can be heated and expand during operation. Such expansion can change the clearance of these portions of the rotor and / or casing when the compressor is operating and can affect the ability of the compressor to function properly and / or efficiently.

US 7955049

  Several embodiments of the invention described in the scope of claims of the present application will be summarized. These embodiments do not limit the technical scope of the invention described in the claims, but merely summarize the possible forms of the present invention. Indeed, the invention is not limited to the embodiments set forth below but encompasses various different embodiments.

  In one embodiment, the system comprises a rotating machine. The rotating machine includes a rotor having a plurality of blades and a split stator having a plurality of stator segments circumferentially arranged around the plurality of blades. Each adjacent pair of first and second segments of the plurality of stator segments includes a recess extending circumferentially across the intermediate joint between the first and second segments. Further, each recess includes one or more eccentric control inserts configured to reduce the eccentricity of the inner circumference of the split stator due to thermal expansion or contraction of the split stator.

  In another embodiment, the system includes an eccentric control insert configured to be attached to a recess in an intermediate joint between adjacent pairs of first and second segments of a split stator of a rotating machine. Furthermore, the eccentric control insert is configured to reduce the eccentricity of the inner periphery of the split stator due to thermal expansion or contraction of the split stator.

  In another embodiment, the system includes a split stator that includes a plurality of stator segments circumferentially disposed about an axis of rotation of the rotating machine. Each adjacent pair of first and second segments of the plurality of stator segments includes a recess extending circumferentially across the intermediate joint between the first and second segments. Further, each recess includes one or more eccentric control inserts configured to reduce eccentricity of the inner circumference of the split stator due to thermal expansion or contraction of the split stator.

  These and other features, aspects and advantages of the present invention may be better understood by reference to the following detailed description taken in conjunction with the drawings in which: Throughout the drawings, like reference numerals are used for like members.

1 is a block diagram of one embodiment of a rotating machine, such as a turbine system, having an eccentric control system for a split stator (eg, split casing). FIG. 1 is a schematic cross-sectional view of an embodiment of a rotary machine, such as a compressor, having an eccentricity control system in which an eccentricity control insert is disposed in a recess in a split stator. FIG. 3 is a schematic cross-sectional view of the split stator of FIG. 2 along line 3-3 showing one embodiment of a recess and an eccentric control insert disposed across an intermediate joint between adjacent stator segments. FIG. 4 is a partial schematic cross-sectional view of the split stator of FIG. 3 taken within line 4-4 showing the arcuate configuration, variable radial thickness, arc length, and other features of the recess and eccentric control insert. FIG. 5 is a partial perspective view of a segment of the split stator of FIGS. 1 to 4 showing a T-shaped joint that couples the eccentric control insert to the recess.

  The following describes one or more specific embodiments of the present invention. In an effort to provide a concise description of these embodiments, all features in an actual implementation may not be described herein. As with any engineering or design project, when developing for implementation, implementation-specific to achieve specific developer goals (such as complying with system and operational constraints) that vary from implementation to implementation It will be clear that many decisions need to be made. Furthermore, while such development efforts may be complex and time consuming, it will be apparent to those of ordinary skill in the art who have access to the disclosure herein only routine design, assembly and manufacture.

  When introducing components of various embodiments of the present invention, what is written in the singular means that there are one or more of the components. The terms “comprising”, “comprising” and “having” are inclusive and mean that there may be additional elements other than the listed components.

  As described above, during system operation, the temperature of the gas present in the rotating system (eg, compressor, gas turbine system turbine, steam turbine, pump or similar rotating system) is relatively high and / or at some point in time. It fluctuates between. These elevated and fluctuating temperatures in the rotating system can cause the portion of the casing (ie, the stator) surrounding the rotor to expand or contract during operation of the system. In addition, the casing of the rotating system may include joined segments, in which case the expansion / contraction of the casing itself or in the vicinity of the joint may not be the same as the central expansion of the casing segment. As a result, the casing (eg, the inner circumference of the casing) is no longer circular (eg, more eccentric) as a result of thermal expansion. For example, if a casing (eg, compressor or turbine) of a rotating system expands and / or contracts during operation, the rotor and a portion of the casing may come into contact with each other, causing premature wear, vibration and / or in the rotating system. Invite cracks. In other examples, if the casing of the rotating system expands and / or contracts in other manners during operation, the clearance between the rotor and the casing becomes too large, reducing the efficiency of the rotating system. In order to control the clearance between the rotor and casing by reducing the eccentricity of the casing when heating and / or cooling during operation of the rotating system, it is generally desirable to improve the casing (ie, stator) design. . The disclosed embodiments use inserts in recesses along each joint between casing segments to help maintain the circularity of the casing (eg, the inner surface of the casing) despite thermal expansion or contraction. .

  In view of the foregoing, FIG. 1 is a block diagram of an embodiment of a turbine system 10 that includes two rotating systems (ie, a compressor and a gas turbine) having an eccentric control system according to aspects of the present technique. . That is, as described in detail below, the casing of the rotating system of turbine system 10 is modified to include an eccentric control insert to help maintain the circularity of the casing despite thermal expansion or contraction. The The illustrated turbine system 10 includes a gas turbine engine 12 coupled to a load 14 such as a generator. The gas turbine engine 12 includes a compressor 16 and a plurality of combustors 18, each having one or more fuel nozzles 20, a turbine 22, and an exhaust 24. As illustrated, one or more shafts 26 connect the load 14, the compressor 16 and the turbine 22. Compressor 16 and turbine 22 each include a rotor with blades that rotate in a stator (ie, casing) that is modified to reduce eccentricity during thermal expansion, as described in detail below. Rotate around 28. In operation, the compressor 16 receives air 30 and supplies compressed air 32 to the combustor 18 and / or fuel nozzle 20, which then burns fuel 34 (or mixture) within the combustor 18. Inject into the area. Eventually, the air-fuel mixture is combusted in the combustor 18 to produce hot combustion gases 36 that drive the blades in the turbine 22. As the turbine is driven to rotate the shaft 26, the compressor 16 is driven to compress the air 16 into the combustor 18 and / or the fuel nozzle 20. For purposes of explanation, reference is made to the axial direction or axis 38, the radial direction or axis 40 and the circumferential direction or axis 42. The axial direction 38 is generally directed along the axis of rotation 28.

  As described above, the illustrated compressor 16 and turbine 22 are modified to reduce the likelihood of a casing that expands or contracts (eg, becomes eccentric) from circularity during operation of the system 10 (ie, is eccentric). , Stator or shroud). Specifically, the disclosed embodiments generally have a portion of each segment of the case chipped or removed near the joint (eg, the removed portion where the individual segments of the case meet). For example, in certain embodiments, the removed portion of the segment near the joint may take the form of a recess, groove, or slot. Furthermore, the disclosed embodiments utilize an insert that can be disposed in a groove or recess to generally control the clearance between the rotor blades and the casing of the rotating machine (eg, compressor 16 or turbine 22). Various aspects of the modified casing embodiment are described below with respect to the compressor 16, but the presently disclosed casing embodiments where a uniform and / or minimal clearance between the rotor and the stator is desired include a gas turbine. It should be understood that it is applicable to 22 or any rotation system.

  FIG. 2 illustrates a cross-sectional view of one embodiment of a compressor 16 having a modified casing in accordance with aspects of the present technique. The illustrated compressor 16 includes a rotor 50 having blades 52 disposed about a shaft 54. Further, the blades 52 of the rotor 50 are configured to rotate within the stator or compressor casing 56 (ie, about the axis of rotation 28). Generally speaking, it is desirable for the casing 56 of the compressor 16 to provide a uniform and minimal clearance 58 between the blades 52 of the rotor 50 and the casing 56. That is, it is generally desirable for the blades 52 of the rotor 50 to be as close as possible to the casing 56 without actually contacting the casing 56 during operation of the compressor 16. It should also be understood that if the clearance 58 between the blades 52 and the casing 56 of the rotor 50 is too large, the efficiency of the compressor 16 can be significantly reduced. For example, for a compressor, a clearance 58 that is 0.254 millimeters (10 mils) greater than the desired clearance may cause the compressor 16 to lose approximately 1 MW of efficiency. In addition, providing a uniform clearance between the rotor and casing over the inner circumference of the casing generally allows the rotating system to have more uniform performance (eg, less variation in power output). it can.

  The casing 56 of the compressor 16 has one or more recesses 60 that support one or more inserts 62 according to aspects of the present technique. Generally speaking, the recess 60 extends radially 40 into the inner surface of the casing 56 (ie, having a radial depth 51 in the wall of the casing 56). In certain embodiments, the recess 60 can be formed by scraping or turning a portion of the casing 56 after manufacture. In other embodiments, the recess 60 can be formed during manufacture of the casing 56 (eg, as an element defined by the mold used to cast the casing 56). Regardless, the recess 60 is the extent of the casing where a portion of the casing material (eg, steel or other suitable metal or alloy) is missing or removed (eg, by cutting or turning). It is. For example, in certain embodiments, the recess 60 can be in the form of a groove, slot, channel, or other similar recess 60. In addition, as described below with reference to FIGS. 3 and 4, the recess 60 is formed in the casing 56 of the compressor 16 at the portion where the various segments of the casing 56 meet (ie, at or near the coupling of the casing segments). Can exist. Further, as described below with reference to FIG. 5, the recess 60 may have a particular shape (eg, V shape, rectangular shape, round shape, or other suitable shape).

  In addition, in the illustrated compressor 16, the insert 62 is disposed in the recess 60. As illustrated, the insert 62 may protrude slightly from the recess 60 into the clearance space 58 in the radial direction 40. For example, the insert 62 may extend approximately 20 mm to 60 mm beyond the inner surface 53 of the casing 56. The illustrated insert 62 also includes two or more layers: a substrate layer 64 and an abradable surface coating 66. In some embodiments, the base layer 64 of the insert 62 may be made from the same material (eg, metal or alloy) as the casing 56. For example, in some embodiments, both the insert 62 and the casing 56 can be manufactured from steel. In other embodiments, the substrate layer 64 of the insert 62 can be made from a different material (eg, metal or alloy) than the casing 56. For example, in some embodiments, the substrate layer 64 of the insert 62 may be a different type of steel (eg, higher carbon steel) than the casing 56. Further, the material used for the substrate layer 64 of the insert 62 may be selected based on the thermal expansion characteristics of the material. That is, the base layer 64 of the insert 62 prevents the insert 62 and casing 56 from expanding or contracting at the same rate when the insert 62 and casing 56 are heated and cooled (eg, during operation of the compressor 16). Furthermore, the casing 56 may have a slightly different thermal expansion characteristic.

  The insert 62 is disposed in the recess 60 so that the abradable surface film 66 faces the blade 52 of the rotor 54. The abradable surface coating 66 can be any surface coating that can be selectively removed upon contact with the blades 52 of the rotor 54 rather than removing material from the rotor blades 52 or casing 56. That is, the blades 52 of the rotor 54 are generally configured not to contact the casing 56, but the aforementioned thermal expansion of the casing 56 during operation of the compressor (eg, the insert 62 or the base material of the casing 56). The blade 52 of the rotor 54 (rather than 64) can be temporarily brought into contact with the abradable surface coating 66 of the insert 62. The abradable surface coating 66 can generally allow tighter clearance 58 while protecting the tip of the blade 52. In addition, the abradable surface coating 66 may generally be considered a self-adjusting coating so that it can be just the tip of the blade 52 until the desired clearance 58 is achieved. In some embodiments, the abradable surface coating 66 can be alumina, silica, titania, chromium carbide or other suitable abradable surface coating 66. In general, the material for the abradable surface coating 66 can be selected according to the relative hardness of the abradable surface coating 66 relative to the casing 56 and the blade 52 of the rotor 54. For example, in certain embodiments, the abradable surface coating 66 is 10%, 20%, 50%, 75% or 95% softer than the material used to manufacture the casing 56 and / or blade 52. It can be manufactured from materials. In addition, as described below with reference to FIGS. 4 and 5, the abradable surface coating 66 may have either a uniform thickness or a variable thickness across the insert 62. .

  FIG. 3 shows a cross-sectional view of the embodiment of the compressor 16 illustrated in FIG. 2 taken within line 3-3 (ie, without the rotor 54 and blades 52). FIG. 3 shows the position of the recess 60 in the casing 56 of the compressor 16 relative to the position of the intermediate joints 70 and 72 (ie, where the first segment 74 and the adjacent second segment 76 meet). While the illustrated embodiment of the casing 56 includes two 180 ° segments (eg, segments 74 and 76), in other embodiments, the casing 56 may include any number of segments (eg, 3, 4, 5, 6 or more) may be included. Further, the illustrated casing 56 includes a generally deeper 59 recess 60 near the joints 70 and 72 and becomes generally shallower 61 as it moves in the circumferential direction 42 away from the joint. In addition, the recess 60 can occupy a portion of the casing 56 measured from the point 73 as an angle 71 at the center of the casing (eg, the rotation axis 38). For example, the illustrated angle 71 is about 60 °. In some embodiments, the angle 71 can be about 10 ° to 60 °, about 20 ° to 50 °, or about 30 ° to 45 °.

  Similarly, the insert 62 disposed in each recess 60 has a thicker portion disposed near the joints 70 and 72 and a thinner portion disposed away from the joint. In addition, in one embodiment, a one-piece or integral insert 6 can be disposed in each of the recesses 60, each of which includes a segment 74 and a segment 76 of the compressor casing 56. Both can occupy the entire recess 60 extending in the circumferential direction 38. In the illustrated embodiment, the recess 60 includes a recess portion 63 and a recess portion 65 that are each fitted with an insert 62. That is, each recess 60 of the illustrated casing 56 includes a first insert 62 (e.g., disposed within the recess portion 63 of the recess 60 in the segment 74) and a recess of the recess 60 (e.g., in the segment 76). Second insert 62) disposed within portion 65.

  In addition, the illustrated casing 56 of the compressor 16 is substantially round (ie, circular). Further, when the casing 56 warms or cools during operation of the compressor 16, a portion of the segments 74 and 76 near the joints 70 and 72 are as large as a portion of the segments 74 and 76 far from the joints 70 and 72. It should be understood that they cannot expand or contract. That is, the casing 56 generally can move more freely in the vicinity of the joints 70 and 72, so that in general (for example, the center 73 of the casing 56 is pushed to the outside 67 or pulled to the inside 69 and the joints 70 and 72 are Deform (e.g., deviate from circularity and / or become eccentric). The illustrated casing 56 has a recess 60 in which the insert 62 is disposed. As casing 56 begins to thermally expand, recess 60 and insert 62 allow compressor casing 56 to thermally expand without substantial eccentricity. That is, the recess 60 and the insert 62 generally allow the clearance 58 between the blades 52 of the rotor 54 to remain substantially uniform throughout the operation of the compressor 16. For example, in some embodiments, the recess 60 and the insert 62 cooperate to provide 1 mm to 50 mm, 5 mm to 30 mm at the joints 70 and 72 (eg, circumferentially 38 between the rotor blade 52, the casing 56, and the insert 62). A uniform clearance 58 of 8 mm to 20 mm, or about 10 mm.

  FIG. 4 shows an enlarged view of the coupling 70 of the embodiment of the casing illustrated in FIG. FIG. 4 shows the recess 60 in the segments 74 and 76 of the casing 56. Also, the illustrated recess 60 is substantially deeper 59 near the joint 70 and substantially shallower 61 away from the joint 70. Further, an insert 62 including a base material 64 and an abradable film 66 is disposed in the illustrated recess 60. Like the illustrated recess 60, the insert 62 is substantially thicker 75 at the portion disposed near the fitting 70 and substantially thinner 77 at the portion disposed away from the fitting 70. In other embodiments, both the recess 60 and the insert 62 may each have a substantially uniform radial 40 depth and thickness. Further, the abradable coating 66 of the illustrated insert 62 is substantially thicker 79 near the fitting 70 and is substantially thinner 81 as it moves away from the fitting 70 in the circumferential direction 42. In certain embodiments, the recess 60, the insert 62, and / or the abradable coating 66 can be described generally as having a generally arcuate shape. In other embodiments, the abradable coating 66 may have a substantially uniform thickness over the length of the insert 62.

  FIG. 5 is a partial perspective view of a segment of the split stator of FIGS. 1-4 showing a T-shaped joint 83 that couples the eccentric control insert 62 to the recess 60. That is, FIG. 5 shows the insert 62 disposed in the recess 60 of the segment 76 of the casing 56. Specifically, the illustrated recess 60 includes a T-shaped joint 83, and the insert 62 is a T-shaped insert 62. In addition, in certain embodiments, the recess 60 and the insert 62 may have a dovetail shape, a round shape, a “V” shape, a triangular shape, a semi-circular shape, and other suitable shapes. Further, the T-shaped joint 83 includes a ridge 85 that can generally serve to hold the insert 62 in place within the T-shaped joint 83. The illustrated T-shaped insert 62 includes a neck portion 89 and a mounting base 91 that extend in the longitudinal direction along the eccentric control insert 62, and the mounting base 91 is wider than the neck portion 89 in the transverse direction with respect to the longitudinal direction. In certain embodiments, the abradable coating 66 of the insert 62 extends beyond the neck portion 89 so that, during operation, the tip blade 52 of the rotor 54 is closest to the abradable coating 66 of the insert 62. In addition, the insert 62 is incorporated into the T-shaped joint 83 from the upper part 85 of the joint 83 so that the insert 62 is mounted circumferentially or attached to the segment 76 of the casing 56 and is downwardly moved. Can be installed in movement 87.

  Further, the illustrated insert 62 is substantially thicker 75 near the fitting 70. That is, both the substrate 64 and the abradable coating 66 of the illustrated insert 62 are substantially thicker 75 near the fitting 70 and move along the segment 76 (ie, away from the fitting 70 in the circumferential direction 42). As shown, the base 64 and abradable coating 66 of the illustrated insert 62 are thinner 77. When the blades 52 of the rotor 54 are rotating during operation of the compressor 16, the grooves 60 and the inserts 62 can provide a uniform circumferential clearance 58 so that the compressor 16 can function efficiently.

  The technical effect of this embodiment is that the stator in the rotor / stator system (e.g., to control the clearance between the rotor and stator as the system expands and / or contracts during heating and / or cooling) Reducing the eccentricity of casings for compressors, gas turbines, steam turbines, pumps and other rotating machinery. By controlling the clearance between the compressor or gas turbine rotor and casing, this embodiment ensures that the compressor or gas turbine functions accurately and efficiently even when the casing expands and contracts during operation. Makes it possible to continue. This embodiment provides an abradable coating that can be selectively removed by reducing the likelihood of contact between the rotor blades in the casing and to preserve the integrity of the rotor blades and / or casing when contacted Thus, maintenance costs can be reduced. Furthermore, this embodiment allows the compressor or gas turbine to maintain efficiency during operation and limit energy and waste.

  This specification discloses the invention, including the best mode, and is described by way of example to enable those skilled in the art to practice the invention, including making and using the device or system and implementing the method. I have done it. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples have components that have no difference in the wording of the claims, or equivalent components that have no substantial difference from the language of the claims. It belongs to the technical scope described in the claims.

DESCRIPTION OF SYMBOLS 10 Turbine system 12 Gas turbine engine 14 Load 16 Compressor 18 Combustor 20 Fuel nozzle 22 Turbine 24 Exhaust part 26 Shaft 28 Rotating shaft 30 Air 32 Compressed air 34 Fuel 50 Rotor 52 Blade 54 Rotor shaft 56 Casing 58 Clearance 60 Recessed part 62 Eccentricity Control insert 63 Recessed portion 64 Base material layer 65 Recessed portion 66 Abbradable film 70 Intermediate joint 72 Intermediate joint

Claims (20)

A system including a rotating machine, wherein the rotating machine is
A rotor having a plurality of blades;
A split stator including a plurality of stator segments circumferentially disposed around the plurality of blades, wherein each adjacent pair of first and second segments of the plurality of stator segments is a first Including a recess extending circumferentially across the intermediate joint between the segment and the second segment, each recess decentering the inner circumference of the split stator due to thermal expansion or contraction of the split stator A system comprising one or more eccentric control inserts configured to reduce.   The system of claim 1, wherein the one or more eccentric control inserts include an abradable portion provided on the base portion.   The system of claim 2, wherein the abradable portion comprises alumina or chromium carbide.   The abradable portion has a first non-uniform thickness circumferentially about the rotation axis of the rotor, and the base has a second non-uniform thickness circumferentially, or a combination thereof The system according to claim 2.   The one or more eccentric control inserts include an arcuate body having an abradable portion provided on the base portion, wherein the arc length of the one or more eccentric control inserts is circumferential about the rotor axis of rotation. The system of claim 2, wherein the system extends at less than about 60 degrees.   Each adjacent pair of recesses of the first segment and the second segment includes a first recess portion disposed in the first segment and a second recess portion disposed in the second segment. The one or more eccentric control inserts comprise a first insert portion disposed in the first recess portion and a second insert portion disposed in the second recess portion. system.   The system of claim 1, wherein the radial depth of the first and second recess portions gradually decreases circumferentially away from the intermediate joint.   The system of claim 1, wherein the radial thickness of the first insert portion and the second insert portion gradually decreases circumferentially away from the intermediate joint.   The recess includes a T-shaped elongated hole, and the one or more eccentric control inserts include one or more T-shaped inserts configured to be mounted in the T-shaped elongated hole circumferentially about the rotational axis of the rotor. Item 1. The system according to Item 1.   The system of claim 1, wherein the rotating machine comprises a compressor or a turbine. A system comprising an eccentric control insert configured to be mounted in a recess in an intermediate joint between adjacent pairs of first and second segments of a rotary stator split stator, wherein the eccentric control insert comprises a split Configured to reduce the eccentricity of the inner circumference of the split stator due to thermal expansion or contraction of the stator,
system.   The length of the arc of the eccentric control insert extends less than about 60 degrees circumferentially about the axis of rotation of the rotating machine, and the eccentric control insert includes an arcuate body having an abradable portion provided on the base portion. 12. The system of claim 11, wherein one or more of the abradable portion or base has a non-uniform thickness in the circumferential direction.   The system of claim 11, wherein the eccentric control insert comprises an abradable material configured to wear to protect a plurality of rotating blades of the rotating machine.   The system of claim 11, wherein an arc length of the eccentric control insert extends less than about 60 degrees circumferentially about a rotational axis of the rotating machine.   The system of claim 11, wherein the radial thickness of the eccentric control insert gradually increases from the first end to the second end circumferentially about the axis of rotation of the rotating machine.   The eccentric control insert includes a neck portion and a mounting base extending in a longitudinal direction along the eccentric control insert, and the mounting base is wider than the neck portion in a transverse direction with respect to the vertical direction. system.   The system of claim 11, comprising a rotating machine having a compressor or turbine. A system including a split stator that includes a plurality of stator segments circumferentially disposed about an axis of rotation of a rotating machine, wherein each adjacent pair of first and second segments of the plurality of stator segments includes: A recess that extends transversely across the intermediate joint between the first segment and the second segment, each recess being an eccentricity of the inner circumference of the split stator due to thermal expansion or contraction of the split stator Including one or more eccentric control inserts configured to reduce
system.   The length of the arc of the eccentric control insert extends less than about 60 degrees circumferentially about the axis of rotation and the eccentric control insert is configured to wear to protect the rotating components of the rotating machine. The system of claim 18 comprising a double material.   The system of claim 18, comprising a rotating machine having a compressor or turbine.