Patent Application
20230175520
Disclosed embodiments relate generally to the field of turbomachinery, and, more particularly, to a rotor structure for a turbomachine, and, even more particularly, to a rotor structure with structural features designed to accommodate or otherwise control relative growth, such as radial and/or axial growth between corresponding axial interface locations.
Turbomachinery is used extensively in the oil and gas industry, such as for performing compression of a process fluid, conversion of thermal energy into mechanical energy, fluid liquefaction, etc. One example of such turbomachinery is a compressor, such as a centrifugal compressor.
As would be appreciated by those skilled in the art, turbomachinery, such as centrifugal compressors, may involve rotors of tie bolt construction (also known in the art as thru bolt or tie rod construction), where the tie bolt supports a plurality of impeller bodies and where adjacent impeller bodies may be interconnected to one another by way of elastically averaged techniques, such as involving hirth couplings or curvic couplings. As would be appreciated by the artisan, these coupling types use different forms of face gear teeth (straight and curved, respectively) to form a coupling between two components. As would be further appreciated by the artisan, these couplings and associated structures are typically subject to greatly varying forces (e.g., centrifugal forces) during operation of the turbomachine.
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., as may involve tens of thousands of RPM) different deflections (e.g., involving relative radial and/or axial growth) may develop at axial interface locations and this relative growth is undesirable. For example, high relative radial and/or axial growth at the axial interface locations could lead to increases in rotor vibration and could further lead to angular misalignments at the axial interface locations that can potentially lead to impaired contact patterns and increased levels of mechanical stresses and distortion at the hirth coupling interfaces.
In view of the foregoing considerations, disclosed embodiments make use of innovative structural features designed to reliably and cost-effectively accommodate or otherwise control or regulate relative radial and/or axial growth between corresponding interface locations, which may be effective for reducing rotor vibration over the life of a given turbomachine. The ability to control relative radial and/or axial growth between corresponding interface locations may be further effective to reduction of angular misalignments at the axial interface locations, which in turn would be effective to establish reliable contact patterns and reduced levels of mechanical stresses and distortion (e.g., angular distortion) at the hirth coupling interfaces.
In the following detailed description, various specific details are set forth in order to provide a thorough understanding of such embodiments. However, those skilled in the art will understand that disclosed embodiments may be practiced without these specific details that the aspects of the present invention are not limited to the disclosed embodiments, and that aspects of the present invention may be practiced in a variety of alternative embodiments. In other instances, methods, procedures, and components, which would be well-understood by one skilled in the art have not been described in detail to avoid unnecessary and burdensome explanation.
Furthermore, various operations may be described as multiple discrete steps performed in a manner that is helpful for understanding embodiments of the present invention. However, the order of description should not be construed as to imply that these operations need be performed in the order they are presented, nor that they are even order dependent, unless otherwise indicated. Moreover, repeated usage of the phrase “in one embodiment” does not necessarily refer to the same embodiment, although it may. It is noted that disclosed embodiments need not be construed as mutually exclusive embodiments, since aspects of such disclosed embodiments may be appropriately combined by one skilled in the art depending on the needs of a given application.
In one disclosed embodiment, a tie bolt 102 extends along a rotor axis 103 between a first end and a second end of the tie bolt 102. A first rotor shaft 1041 may be fixed to the first end of tie bolt 102. A second rotor shaft 1042 may be fixed to the second end of tie bolt 102. Rotor shafts 1041, 1042 may be referred to in the art as rotor shafts. A plurality of impeller bodies 106, such as impeller bodies 1061 through 106n, may be disposed between rotor shafts 1041, 1042. In the illustrated embodiment, the number of impeller bodies is six and thus n=6; it will be appreciated that this is just one example and should not be construed in a limiting sense regarding the number of impeller bodies that may be used in disclosed embodiments. The embodiment illustrated in
The plurality of impeller bodies 106 is supported by tie bolt 102 and is mechanically coupled to one another along the rotor axis by way of a plurality of hirth couplings, such as hirth couplings 1081 through 108n−1. In the illustrated embodiment, since as noted above, the number of impeller bodies is six, then the number of hirth couplings would be five. It will be appreciated that two additional hirth couplings 1091 and 1092 may be used to respectively mechanically couple the impeller bodies 106n, 1061 respectively proximate to the first and second ends of tie bolt 102 to rotor shafts 1041, 1042.
In disclosed embodiments, as may be better conceptually appreciated in respective zoomed-in views 114 and 116 of non-limiting representative impeller bodies 1065 and 1062, a radially-inner contour of an impeller body 106 of the plurality of impeller bodies may be characterized by at least two distinct axially-extending zones (e.g., Z1, Z3) each having a respective geometry configured to control relative radial and/or axial growth between corresponding interface locations along the rotor axis at which corresponding faces 110 (
In one non-limiting embodiment, the respective geometry of the at least two axially-extending zones may be characterized by a differing bore diameter size (e.g., D1, D2, D3). That is, the respective bore diameters of zones Z1, Z2, Z3 may each have different sizes relative to one another. In another non-limiting embodiment, the respective geometry of the at least two axially-extending zones (e.g., zones Z1, Z2, Z3) may be characterized by a differing axial length (e.g., L1, L2 L3). That is, the respective axial lengths of zones Z1, Z2, Z3 may each have different lengths relative to one another. In still another non-limiting embodiment, the respective geometry of the at least two axially-extending zones may be characterized by at least one of the following: a differing bore diameter size, and a differing axial length. That is, a differing bore diameter size or a differing axial length, or both.
Because of cross-sectional shape resemblance, without limitation, first axially-extending zone Z1 may be conceptually analogized to the toe section in an stiletto-style shoe; second-axially-extending zone Z3 may be conceptually analogized to the heel section of the shoe; and intermediate axially-extending zone Z2 may be conceptually analogized to the shank section disposed between the toe section and the heel section of the shoe.
Accordingly, in view of the above-noted shape resemblance, first axially-extending zone Z1 may be referred to as an impeller toe section; second-axially-extending zone Z3 may be referred to as an impeller heel section; and intermediate axially-extending zone Z2 may be referred to as an impeller shank section. The respective geometry of such toe, shank and heel impeller sections may each be configured to control the relative radial and/or axial growth that, for example, can develop between the impeller heel section and toe section of certain adjacent impellers, such as between the toe section of impeller body 1065 and the heel section of impeller body 106n; or, in another example, can develop between the respective impeller heel sections of adjacent impellers at the midspan of tie bolt 102, such as between the heel section of impeller body 1063 and the corresponding heel section of impeller body 1064.
Without limitation, the respective geometries of such sections of the impeller bodies may be appropriately configured to appropriately balance mass distribution and in effect balance the mass moment of inertia about the axis of rotation of the impeller bodies so that in turn the respective resulting centrifugal forces that develop in the toe, shank and heel impeller sections are appropriately balanced (e.g., in the impeller body illustrated in the zoomed-in view 114, the respective resulting centrifugal forces are schematically represented by arrows Fz1, Fz2 and Fz3).
The foregoing structural and/or operational relationships are conducive in disclosed embodiments to control the relative radial and/or axial growth that can develop between corresponding interface locations along the rotor axis at which corresponding faces 110 of a respective hirth coupling 108 mesh or otherwise engage with one another, such as between the corresponding impeller heel section and toe section of certain adjacent impeller bodies.
It will be appreciated that the zoomed-in views 114 and 116 shown in
By way of example, second axially-extending zone Z3 of the radially-inner contour of the impeller body may be located axially downstream relative to first axially-extending zone Z1 of the radially-inner contour of impeller body 106 and relative to an inlet eye 112 of impeller body 106.
As may be better appreciated in
As suggested above, an axial side of the first axially-extending zone Z1 of impeller body 106, proximate to the first end of tie bolt 102 is mechanically coupled to first rotor shaft 1041 by way of a further hirth coupling (e.g., hirth coupling 1091). In this case, as illustrated in
The foregoing structural and/operational relationships are equally applicable to the axial side of first axially-extending zone Z1 of impeller body 1061, which is proximate to the second end of the tie bolt and which is mechanically coupled to second rotor shaft 1042 by way of another hirth coupling (e.g., hirth coupling 1092). Accordingly, to spare the reader from pedantic and burdensome repetitive details, the foregoing structural and/operational relationships will not be disclosed again.
In operation, disclosed embodiments include structural and/or operational relationships (e.g., distinct axially-extending zones in the radially-inner contour of respective impeller bodies configured to balance mass distribution about the rotor axis) designed to control relative radial and/or axial growth between corresponding interface locations, thereby reducing rotor vibration over the life of a given turbomachine. Additionally, in operation disclosed embodiments offer superior and reliable contact pattern and reduced annular distortion at hirth coupling interfaces.
While embodiments of the present 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 therein without departing from the scope of the invention and its equivalents, as set forth in the following claims.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2020/032936 | 5/14/2020 | WO |
