Rotor structure for a turbomachine having features for controlled relative growth of the axial joint

Abstract

A rotor structure for a turbomachine, such as a centrifugal compressor, is provided. The disclosed embodiments take advantage of structural and / or operational relationships (e.g., different axially-extending regions in the radially-inner profile of the respective impeller body are configured to balance the mass distribution about the rotor axis) that are designed to control the relative radial and / or axial growth along the rotor axis between corresponding engagement locations at which corresponding faces of the respective end tooth disc couplings mesh with one another. The ability to control the relative radial and / or axial growth between the corresponding engagement locations can effectively reduce rotor vibrations and / or establish a more reliable contact pattern and reduced levels of mechanical stresses and deformations (e.g., angular deformations) at the end tooth disc coupling engagement.

Description

BACKGROUND 1. TECHNICAL FIELD

[0002] The disclosed embodiments relate generally to the field of turbomachinery, and more specifically, to rotor structures for turbomachines, and even more specifically, to rotor structures having structural features designed to accommodate or otherwise control relative growth, such as radial and / or axial growth between corresponding axial joint locations. 2. BACKGROUND

[0004] Turbomachinery is widely used in the oil and gas industry, such as for performing compression of process fluids, conversion of thermal energy to mechanical energy, fluid liquefaction, etc. One example of such turbomachinery is a compressor, such as a centrifugal compressor. BRIEF DESCRIPTION OF DRAWINGS

[0005] Figure 1 illustrates a partial cross-sectional view of one non-limiting embodiment of a disclosed rotor structure, as can be used in industrial applications involving turbomachinery, such as but not limited to centrifugal compressors.

[0006] Figure 2 and Figure 3 respectively illustrate Figure 1 enlarged views of portions of the rotor structure shown in Figure 2 and Figure 3 may be used to illustrate and describe certain non-limiting structural and / or operational relationships pertaining to the disclosed rotor structure. DETAILED DESCRIPTION

[0007] As will be appreciated by those skilled in the art, turbomachinery, such as centrifugal compressors, can involve rotors of a tension bolt construction (also referred to in the art as a through bolt or tie rod construction), where the tension bolts support a plurality of impeller bodies, and where adjacent impeller bodies can be interconnected to one another by elastic averaging techniques, such as involving end tooth disc couplings or flex couplings. As will be appreciated by the skilled artisan, these coupling types use different forms of face gear teeth (straight and curved, respectively) to form a coupling between two components. As will be further appreciated by the skilled artisan, these couplings and associated structures are typically subjected to varying forces (e.g., centrifugal forces) during operation of the turbomachine.

[0008] The present inventors have recognized that, during operation of known turbomachinery, such as from an initial rotor speed of zero revolutions per minute (RPM) to a maximum rotor speed (e.g., possibly involving tens of thousands of revolutions per minute), different deflections (e.g., involving relative radial and / or axial growth) can occur at the axial junction locations, but this relative growth is undesirable. For example, high relative radial and / or axial growth at the axial junction locations can result in an increase in rotor vibration, and can further result in angular misalignment at the axial junction locations, which can potentially result in impaired contact patterns and increased levels of mechanical stress and distortion at the end tooth disc coupling junctions.

[0009] In view of the foregoing considerations, the disclosed embodiments utilize innovative structural features designed to reliably and cost-effectively accommodate or otherwise control or regulate relative radial and / or axial growth between the corresponding junction locations, which can effectively reduce rotor vibration over the lifetime of a given turbomachine. The ability to control relative radial and / or axial growth between the corresponding junction locations can further effectively reduce angular misalignment at the axial junction locations, which in turn will effectively establish reliable contact patterns and reduced levels of mechanical stress and distortion (e.g., angular distortion) at the end tooth disc coupling junctions.

[0010] In the following detailed description, various specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. However, persons of ordinary skill in the art will understand that the disclosed embodiments can be practiced without these specific details, that the aspects of the present disclosure are not limited to the disclosed embodiments, and that aspects of the present disclosure can be practiced in a variety of alternative embodiments. In other instances, well-known methods, procedures and components have not been described in detail so as not to unnecessarily obscure aspects of the present disclosure.

[0011] Further, various operations can be described as multiple discrete steps performed in turn, in part because more practical implementations can be more trouble-some to describe in a single step. However, unless otherwise indicated, the order of description should not be construed as to imply that these operations are order dependent. Further, the repetition of the phrase "in one embodiment" does not necessarily refer to the same embodiment, although it can. Lastly, the various embodiments of the disclosed technology need not be mutually exclusive, as some aspects of the disclosed embodiments can be appropriately combined by one of skill in the art in light of the given application's needs.

[0012] Figure 1A partial cross-sectional view of one non-limiting embodiment of a disclosed rotor structure 100 is illustrated, as can be used in industrial applications involving turbomachinery, such as but not limited to compressors (e.g., centrifugal compressors, etc.).

[0013] In one disclosed embodiment, the tie bolt 102 extends along the rotor axis 103 between a first end and a second end of the tie bolt 102. The first end of the tie bolt 102 can be fixed with a first rotor shaft 1041. The second end of the tie bolt 102 can be fixed with a second rotor shaft 1042. The rotor shafts 1041, 1042 can be referred to in the art as rotor spools. A plurality of impeller bodies 106, such as impeller bodies 1061-106 n In the illustrated embodiment, the number of impeller bodies is six, and thus n = 6; it will be understood that this is merely one example and should not be construed as limiting as to the number of impeller bodies that can be used in the disclosed embodiments. Figure 1 The illustrated embodiment in FIG. 1 involves a central suspension configuration of back-to-back impeller stages; it will be understood that this is merely one example configuration and should not be construed as limiting as to the applicability of the disclosed embodiments.

[0014] The plurality of impeller bodies 106 are supported by the tie bolt 102 and coupled by a plurality of end tooth disc couplings, such as end tooth disc couplings 1081-108 n-1 are mechanically coupled to one another along the rotor axis. In the illustrated embodiment, since the number of impeller bodies is six as noted above, the number of end tooth disc couplings will be five. It will be understood that two additional end tooth disc couplings 1091 and 1092 can be used to mechanically couple the impeller bodies 106 n , 1061 proximate the first and second ends of the tie bolt 102, respectively, to the rotor shafts 1041, 1042, respectively.

[0015] In the disclosed embodiments, as can be better conceptually understood in the respective enlarged views 114 and 116 of non-limiting representative impeller bodies 1065 and 1062, the radially inner profile of an impeller body 106 of the plurality of impeller bodies can be characterized by at least two distinct axially extending regions (e.g., Z1, Z3) each having a respective geometry configured to control the relative radial and / or axial growth between corresponding engagement locations along the rotor axis at which a corresponding face 110 Figure 1) mesh with or otherwise engage one another. In one non-limiting embodiment, three different axially extending regions such as a first axially extending region Z1, a second axially extending region Z3, and an intermediate axially extending region Z2 disposed between the first axially extending region Z1 and the second axially extending region Z3 can be involved.

[0016] In one non-limiting embodiment, the respective geometric features of the at least two axially extending regions can be characterized by different aperture sizes (e.g., D1, D2, D3). That is, the respective aperture sizes of the regions Z1, Z2, Z3 can each have different sizes relative to one another. In another non-limiting embodiment, the respective geometric features of the at least two axially extending regions (e.g., regions Z1, Z2, Z3) can be characterized by different axial lengths (e.g., L1, L2, L3). That is, the respective axial lengths of the regions Z1, Z2, Z3 can each have different lengths relative to one another. In yet another non-limiting embodiment, the respective geometric features of the at least two axially extending regions can be characterized by at least one of: different aperture sizes; and different axial lengths. That is, different aperture sizes, or different axial lengths, or both different aperture sizes and different axial lengths.

[0017] Due to the similarity in cross-sectional shape, non-limitingly, the first axially extending region Z1 can be conceptually analogous to a toe section of a high-heeled shoe; the second axially extending region Z3 can be conceptually analogous to a heel section of a shoe; and the intermediate axially extending region Z2 can be conceptually analogous to a shank section disposed between the toe section and the heel section of a shoe.

[0018] Accordingly, in view of the above shape similarity, the first axially extending region Z1 can be referred to as a vane toe section; the second axially extending region Z3 can be referred to as a vane heel section; and the intermediate axially extending region Z2 can be referred to as a vane shank section. The respective geometric features of such toe, shank, and heel vane sections can each be configured to control relative radial and / or axial growth, for example, can produce relative radial and / or axial growth between the heel section and the toe section of certain adjacent vanes, such as between the toe section of the vane body 1065 and the heel section of the vane body 106 n ; or, in another example, can produce relative radial and / or axial growth between the respective heel sections of adjacent vanes at the midspan of the tension bolt 102, such as between the heel section of the vane body 1063 and the corresponding heel section of the vane body 1064.

[0019] Without limitation, the respective geometries of these segments of the impeller body can be suitably configured to suitably balance the mass distribution and effectively balance the mass moment of inertia about the rotation axis of the impeller body, in turn causing the resulting synthetic centrifugal forces generated in the toe, shank and heel impeller segments to be suitably balanced (e.g., in the impeller body illustrated in the enlarged view 114, the respective resulting synthetic centrifugal forces are schematically represented by arrows F z1 Z2 Z3 .

[0020] In the disclosed embodiments, the following structural and / or operational relationships contribute to control the relative radial and / or axial growth that can be generated along the rotor axis between the corresponding engagement positions at which the corresponding faces 110 of the respective end-toothed disc couplings 108 mesh or otherwise engage one another, such as between the corresponding impeller heel and toe segments of certain adjacent impeller bodies.

[0021] It will be appreciated that Figure 1 The enlarged views 114 and 116 of the impeller body 106 shown in FIGS. 1 1 1 and 1 12 illustrate constant hole diameters in relation to the zones Z1, Z2, Z3; it will be appreciated that these zones need not have constant hole diameters. For example, the respective geometry of the intermediate zone Z2 can be characterized by a varying hole diameter along the rotor axis 103. In one non-limiting embodiment, the maximum value of the varying hole diameter of the intermediate zone Z2 can be greater relative to the respective hole diameters D1, D3 of the first and second axially extending zones Z1, Z3. That is, if the radially inner profile of the intermediate zone Z2 is rotated about the rotation axis (e.g., the rotor axis 103), the resulting surface of revolution need not be a cylindrical surface, but rather, without limitation, can be at least one conical surface or another non-cylindrical surface of revolution or a combination of these surfaces.

[0022] By way of example, the second axially extending zone Z3 of the radially inner profile of the impeller body can be axially downstream relative to the first axially extending zone Z1 of the radially inner profile of the impeller body 106 and relative to the entry aperture 1 12 of the impeller body 106.

[0023] As in Figure 2 ​​As can be better understood, the opposing axial sides of the first axial extension region Z1 and the second axial extension region Z3 of adjacent impeller bodies 106 can define corresponding recesses 120, which are configured to receive radially outward portions 130 of the corresponding meshing faces of the respective end-gear couplings 108. Since the corresponding recesses 120 defined by the opposing axial sides of the first axial extension region Z1 and the second axial extension region Z3 of adjacent impeller bodies 106 undergo controlled relative radial and / or axial growth, this feature effectively suppresses misalignment and / or mechanical stress that might otherwise occur between the corresponding faces of the respective end-gear couplings.

[0024] As described above, the impeller body 106 near the first end of the tension bolt 102 n The axial side of the first axially extended region Z1 is mechanically connected to the first rotor shaft 1041 via another end geared disc connector (e.g., end geared disc connector 1091). In this case, as... Figure 3 As shown, the impeller body 106 n The axial side of the first axially extended region Z1 and the corresponding axial surface of the first rotor shaft 1041 define a corresponding recess 140, which is used to support the radially outward portion 150 of the corresponding surface of the other end gear disk connector 1091. Due to the impeller body 106 n The corresponding notches defined by the axial side of the first axial extension region and the corresponding axial surface of the first rotor shaft 1041 are subject to controlled relative radial and / or axial growth, thus effectively suppressing misalignment and / or mechanical stress that might otherwise occur between the corresponding surfaces of the end gear coupling 1091.

[0025] The aforementioned structural and / or operational relationships also apply to the axial side of the first axially extending region Z1 of the impeller body 1061, which is located near the second end of the tension bolt and mechanically connected to the second rotor shaft 1042 via another end gear coupling (e.g., end gear coupling 1092). Therefore, to spare the reader tedious and repetitive details, the aforementioned structural and / or operational relationships will not be disclosed further.

[0026] In operation, the disclosed embodiments include structural and / or operational relationships (e.g., different axially extending regions in the radial inner profile of the respective impeller body are configured to balance the mass distribution about the rotor axis), which are designed to control the relative radial and / or axial growth between corresponding engagement locations, thereby reducing rotor vibration over a given turbine life. Furthermore, in operation, the disclosed embodiments provide excellent and reliable contact modes and reduced circumferential deformation at the end-tooth disc coupling engagement.

[0027] While the embodiments of the disclosure have been disclosed in exemplary forms, it will be apparent to those skilled in the art that many modifications, additions and deletions can be made to the embodiments of the disclosure as set forth in the claims without departing from the scope of the disclosure and its equivalents as set forth in the following claims.

Claims

1. A rotor structure for a compressor, the rotor structure comprising: a tie bolt extending along a rotor axis between a first end and a second end of the tie bolt; a first rotor shaft fixed to the first end of the tie bolt; a second rotor shaft fixed to the second end of the tie bolt; a plurality of impeller bodies disposed between rotor shafts, the plurality of impeller bodies being supported by the tie bolt and mechanically coupled to one another along the rotor axis by a plurality of end tooth disc couplings, wherein a radially inner profile of the impeller bodies comprises a first axially extending region, a second axially extending region, and an intermediate axially extending region disposed between the first and second axially extending regions, wherein the radially inner profile of an impeller body of the plurality of impeller bodies is characterized by at least two axially extending regions that each have a respective geometry configured to balance a mass distribution about the rotor axis and to control a relative radial and / or axial growth between corresponding engagement locations along the rotor axis at which corresponding faces of a respective end tooth disc coupling of the plurality of end tooth disc couplings mesh with one another, and wherein the respective geometry of the intermediate axially extending region is characterized by a varying bore diameter along the rotor axis, wherein a maximum of the varying bore diameter of the intermediate axially extending region is greater relative to respective bore diameters of the first and second axially extending regions.

2. The rotor structure of claim 1, wherein, the respective geometries of the at least two axially extending regions are characterized by different bore diameters.

3. The rotor structure of claim 1, wherein, the respective geometries of the at least two axially extending regions are characterized by different axial lengths.

4. The rotor structure of claim 1, wherein, the respective geometries of the at least two axially extending regions are characterized by at least one of: different bore diameters; and different axial lengths.

5. The rotor structure of claim 1, wherein, the second axially extending region of the radially inner profile of the impeller body is axially downstream relative to the first axially extending region of the radially inner profile of the impeller body and relative to an entry bore of the impeller.

6. The rotor structure of claim 5, wherein, mutually opposing axial sides of the first and second axially extending regions of the radially inner profile of the impeller body define respective notches configured to receive radially outward portions of the corresponding faces of the respective end tooth disc couplings that mesh with one another.

7. The rotor structure of claim 6, wherein, the respective notches defined by the mutually opposing axial sides of the first and second axially extending regions of the radially inner profile of the impeller body, which are subject to controlled relative radial and / or axial growth, effectively inhibit misalignment between the corresponding faces of the respective end tooth disc couplings that mesh with one another.

8. The rotor structure of claim 1, wherein, An axial side of a first axially extending region of a radially inner profile of an impeller body proximate to the first end of the tension bolt is mechanically coupled to the first rotor shaft by a further end tooth disc coupling, wherein the axial side of the first axially extending region of the impeller body proximate to the first end of the tension bolt and a corresponding axial face of the first rotor shaft define respective notches of radially outward portions of corresponding faces of the further end tooth disc coupling that mesh with each other.

9. The rotor structure of claim 8, wherein, The respective notches defined by the axial side of the first axially extending region of the impeller body proximate to the first end of the tension bolt and the corresponding axial face of the first rotor shaft that are subject to controlled relative radial and / or axial growth effectively inhibit misalignment between the corresponding faces of the further end tooth disc coupling.

10. The rotor structure of claim 8, wherein, An axial side of a first axially extending region of a radially inner profile of an impeller body proximate to the second end of the tension bolt is mechanically coupled to the second rotor shaft by a further end tooth disc coupling, wherein the axial side of the first axially extending region of the impeller body proximate to the second end of the tension bolt and a corresponding axial face of the second rotor shaft define respective notches of radially outward portions of corresponding faces of the further end tooth disc coupling that mesh with each other.

11. The rotor structure of claim 10, wherein, The respective notches defined by the axial side of the first axially extending region of the impeller body proximate to the second end of the tension bolt and the corresponding axial face of the second rotor shaft that are subject to controlled relative radial and / or axial growth effectively inhibit misalignment between the corresponding faces of the further end tooth disc coupling.

12. The rotor structure of claim 1, wherein, The respective rotational surfaces defined by the respective axially extending regions of the first axially extending region, the second axially extending region, and the intermediate axially extending region are selected from the group consisting of: a cylindrical rotational surface, a conical rotational surface, and a combination of a cylindrical rotational surface and a conical rotational surface.

13. A centrifugal compressor comprising the rotor structure according to any one of claims 1 to 12.

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