A gas turbine and a casing structure thereof

Abstract

The application discloses a gas turbine and a casing structure thereof, and relates to the technical field of gas turbines. The casing structure comprises an outer casing and an inner casing; the outer casing and the inner casing are both split casings; the cross section of the outer casing is in the shape of a pseudo-C letter, so that an annular cavity in the shape of a T letter in cross section is formed in the inner part of the outer casing; the inner casing is arranged in the annular cavity; a limiting module is further arranged between the outer casing and the inner casing, and the limiting module is used at least for limiting the circumferential relative displacement generated between the outer casing and the inner casing. By adopting the split outer casing in the shape of a pseudo-C letter in cross section, the T letter-shaped annular cavity is formed in the inner part of the outer casing, the inner casing is nested in the annular cavity, the axial and radial limiting of the inner casing and the outer casing can be automatically realized, a large number of bolts are not needed for connection and positioning, the number of parts and the assembly process are reduced, and the production manufacturing cost is reduced.

Description

Technical Field

[0001] This application relates to the field of gas turbine technology, specifically a gas turbine and its casing structure. Background Technology

[0002] Gas turbines operate under harsh conditions of high temperature and high pressure for extended periods, making components such as hot-end blades prone to creep and cracking. On-site cylinder disassembly and maintenance capabilities can significantly shorten repair cycles and avoid high return-to-factory costs and prolonged downtime. Therefore, current technology generally uses a split-type casing for the outer and inner casings. Specifically, a split-type casing refers to a casing structure where the overall annular casing is symmetrically divided into an upper and lower half along the axial midline of the gas turbine. These two halves are fastened together at the midline using circumferentially distributed flanges and connecting bolts, forming a complete, closed annular cavity. For the hot-end casing of a gas turbine, the core advantage of the axially split, two-section design is that during maintenance, only the connecting bolts at the split surface need to be removed to lift and separate the upper casing. This eliminates the need for complete disassembly of the gas turbine rotor, bearing housings, and upstream and downstream intake, exhaust, and fuel pipelines. It allows direct exposure of core hot-end components inside the casing, such as the moving blades, stationary blades, sealing rings, and combustion chamber, enabling rapid on-site inspection, troubleshooting, and replacement of vulnerable parts. However, traditional split casings require numerous bolts to connect and position the outer and inner casings, resulting in a large number of parts, high manufacturing costs, and a cumbersome assembly and disassembly process, impacting maintenance efficiency. Summary of the Invention

[0003] The purpose of this application is to provide a gas turbine and its casing structure to solve the technical problems of cumbersome bolt connections, high cost, and low maintenance efficiency of traditional split casings.

[0004] To achieve the above objectives, this application provides the following technical solution:

[0005] In a first aspect, this application proposes a casing structure. The casing structure includes an outer casing and an inner casing; both the outer casing and the inner casing are split-type casings; the cross-section of the outer casing is C-shaped, so that the interior of the outer casing forms an annular cavity with a T-shaped cross-section; the inner casing is disposed within the annular cavity; a limiting module is further provided between the outer casing and the inner casing, the limiting module being used at least to limit the circumferential relative displacement between the outer casing and the inner casing.

[0006] As a specific solution in this application, the limiting module includes: A first limiting groove is provided in the inner casing; A limiting hole is provided in the outer casing; the limiting hole corresponds to the first limiting groove, and the inner diameter of the limiting hole is larger than the inner diameter of the first limiting groove; The limiting pin is both in an interference fit with the first limiting groove and in an interference fit with the limiting hole.

[0007] As a specific solution in this application, the limiting module includes: A first limiting groove is provided in the inner casing; A second limiting groove is disposed in the outer casing; the second limiting groove corresponds to the first limiting groove; The limiting post is adapted to the first limiting groove and the second limiting groove respectively; the first length is greater than the first depth, the first length is the length of the limiting post along the first direction; the first depth is the depth of the second limiting groove along the first direction; the first direction is parallel to the axial direction of the inner casing; A first elastic element is disposed between the first limiting groove and the limiting post, for generating a counterforce parallel to the first direction between the limiting post and the second limiting groove; and the sum of the first length and the second length is less than or equal to the second depth; the second length is the minimum length formed by the first elastic element after being compressed along the first direction within the elastic deformation range; the second depth is the depth of the first limiting groove along the first direction.

[0008] As a specific solution in this application, the outer casing is further provided with a disassembly hole corresponding to the limiting post; the inner diameter of the disassembly hole is smaller than the inner diameter of the second limiting groove.

[0009] As a specific solution in this application, it also includes multiple casing protrusions; each casing protrusion is disposed between the outer casing and the inner casing, and each casing protrusion is distributed circumferentially around the inner casing; two adjacent casing protrusions form cooling channels with the inner wall surface of the outer casing and the outer wall surface of the inner casing.

[0010] As a specific solution in this application, it also includes an adjustment module, which is disposed in the outer casing or the inner casing and is used to adjust the opening of the cooling channel.

[0011] As a specific solution in this application, the adjustment module includes an adjustment ring, which is threadedly connected to the outer casing or the inner casing by a plurality of fastening bolts.

[0012] As a specific embodiment of the technical solution in this application, the adjusting ring is elastic; and the adjusting ring includes a curved section and a horizontal section, so that the radial width of the adjusting ring is positively correlated with the axial compressive force applied to the adjusting ring.

[0013] As a specific embodiment of the technical solution in this application, the cross-section of the adjusting ring is shaped like the number 7, and the bolt shank of each fastening bolt moves through the adjusting ring; the casing structure also includes a second elastic element corresponding to each fastening bolt; each second elastic element is located between the adjusting ring and the casing, and each second elastic element is used to apply an elastic force along a second direction to the adjusting ring; the second direction is parallel to the axis of the fastening bolt corresponding to the second elastic element, and points from the bolt shank of the fastening bolt to the bolt head.

[0014] Secondly, this application proposes a gas turbine. The gas turbine includes a casing structure as described in any one of the first aspects.

[0015] Compared with the prior art, the beneficial effects of this application are: This application employs a split outer casing with a C-shaped cross-section, forming a T-shaped annular cavity within it to nest an inner casing. This allows for automatic axial and radial positioning of the inner and outer casings, eliminating the need for numerous bolts for connection and positioning. This reduces the number of parts and assembly steps, lowering manufacturing costs. During maintenance, only the circumferential constraints of the positioning module need to be released for rapid separation of the inner and outer casings. This retains the core advantage of on-site cylinder opening maintenance with a split casing, eliminating the need for complete disassembly of the gas turbine rotor, bearing housings, and upstream and downstream piping systems. It allows direct exposure of internal hot-end components, significantly improving maintenance efficiency, effectively shortening gas turbine downtime maintenance cycles, and reducing downtime losses and return-to-factory repair costs. Attached Figure Description

[0016] Figure 1 This is a front view schematic diagram of a casing structure proposed in an embodiment of this application; Figure 2 for Figure 1 A cross-sectional view of the middle casing structure (the cross-sectional plane is perpendicular to the casing axis). Figure 3 A partial embodiment of the casing structure proposed in this application is based on... Figure 1 A cross-sectional view of the orientation indicated by line AA in the middle; Figure 4 for Figure 3 An enlarged schematic diagram of a structure in section D; Figure 5 for Figure 3 An enlarged schematic diagram of another structure of part D in the middle; Figure 6Another casing structure proposed in the embodiments of this application is partially in accordance with Figure 1 Schematic diagram of the cross section along line AA; Figure 7 Another casing structure proposed in the embodiments of this application is partially in accordance with Figure 1 Schematic diagram of the cross section along line AA; Figure 8 Another casing structure proposed in the embodiments of this application is partially in accordance with Figure 1 Schematic diagram of the cross section along line AA.

[0017] In the diagram: 1. Outer casing; 2. Inner casing; 3. Casing protrusion; 4. Cooling channel; 61. Limiting pin; 62. First limiting groove; 63. Second limiting groove; 64. First elastic element; 65. Limiting post; 66. Disassembly hole; 67. Limiting hole; 71. Adjusting ring; 711. Bending section; 712. Horizontal section; 72. Fastening bolt; 73. Second elastic element. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] It should be noted that in the description of this application, the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0020] Furthermore, it should be understood that, for ease of description, the dimensions of the various components shown in the accompanying drawings are not drawn to actual scale; for example, the thickness or width of some layers may be exaggerated relative to other layers.

[0021] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined or described in one figure, it will not need to be discussed or described in detail in the description of the subsequent figures.

[0022] To address the technical problems mentioned in the background art, such as the cumbersome bolt connections, high cost, and low maintenance efficiency of traditional split-type casings, this application proposes a casing structure. This casing structure includes an outer casing 1 and an inner casing 2, both of which are split-type casings. Figure 3 As shown, the outer casing 1 has a C-shaped cross-section, so that the interior of the outer casing 1 forms an annular cavity with a T-shaped cross-section, and the inner casing 2 is disposed in the annular cavity. A limit module is also provided between the outer casing 1 and the inner casing 2, which is used to limit the circumferential relative displacement between the outer casing 1 and the inner casing 2.

[0023] This embodiment employs a split outer casing with a C-shaped cross-section, forming a T-shaped annular cavity inside the outer casing to nest the inner casing, achieving axial and radial positioning of the outer and inner casings. A positioning module further enables circumferential positioning and limiting of the outer and inner casings. Eliminating the need for numerous bolts for connecting and positioning the outer and inner casings reduces the number of parts and assembly steps, lowering manufacturing costs. Furthermore, during maintenance, simply releasing the positioning module allows for rapid separation of the outer and inner casings, improving work efficiency and shortening gas turbine shutdown and maintenance cycles.

[0024] In this embodiment, the limiting module is not subject to many restrictions, as long as it can limit the circumferential relative displacement between the outer casing 1 and the inner casing 2. For example, in one embodiment of this application, the limiting module may include a first limiting groove 62, a limiting hole 67, and a limiting pin 61. Figure 5 As shown, a first limiting groove 62 is disposed in the inner casing 2, and a limiting hole 67 is disposed in the outer casing 1. The limiting hole 67 corresponds to the first limiting groove 62, and the inner diameter of the limiting hole 67 is larger than the inner diameter of the first limiting groove 62. The limiting pin 61 is in an interference fit with both the first limiting groove 62 and the limiting hole 67.

[0025] In use, if it is necessary to achieve circumferential limiting of the outer casing 1 and the inner casing 2, the inner casing 2 is first embedded into the annular cavity of the outer casing 1, and the first limiting groove 62 of the inner casing 2 is precisely aligned with the limiting hole 67 of the outer casing 1. Then, the limiting pin 61 is inserted from the limiting hole 67, so that it forms an interference fit with the first limiting groove 62 and the limiting hole 67 at the same time, which can limit the relative circumferential displacement of the outer casing 1 and the inner casing 2 and complete the circumferential limiting.

[0026] In this embodiment, the correspondence between the limiting hole 67 and the first limiting groove 62 means that when the inner casing 2 is fully embedded in the T-shaped annular cavity of the outer casing 1, and the center lines of the outer casing 1 and the inner casing 2 coincide and their axial and radial positions are precisely aligned, the center line of the limiting hole 67 and the center line of the first limiting groove 62 are completely collinear, so as to ensure that the limiting pin 61 can be smoothly inserted into the limiting hole 67 and the first limiting groove 62.

[0027] It is important to note that if the limiting pin 61 is both interference-fitted with the first limiting groove 62 and the limiting hole 67, during the long-term high-temperature operation of the gas turbine, the outer casing 1 and the inner casing 2 may undergo different degrees of thermal expansion deformation due to the operating temperature gradient. The interference-fitted limiting pin 61 will be firmly stuck by the compressive force generated by the thermal deformation. This may not only prevent the limiting pin 61 from being pulled out normally during casing maintenance, but also cause permanent structural damage such as scratches and cracks on the inner wall of the first limiting groove 62 or the limiting hole 67 if forcibly disassembled. At the same time, the rigid interference fit will completely restrict the free thermal deformation of the outer casing 1 and the inner casing 2, generating additional thermal stress that cannot be released inside the casing (i.e., the outer casing 1 or the inner casing 2). Under long-term alternating loads, this will accelerate the initiation and propagation of fatigue cracks in the casing and reduce the service life of the casing. To overcome the inherent defects of rigid interference limiting, in one embodiment of this application, the limiting module may include a first limiting groove 62, a second limiting groove 63, a limiting post 65, and a first elastic element 64. Wherein, as... Figure 4 As shown, a first limiting groove 62 is disposed in the inner casing 2. A second limiting groove 63 is disposed in the outer casing 1, and the second limiting groove 63 corresponds to the first limiting groove 62. A first elastic member 64 is disposed between the first limiting groove 62 and the limiting post 65, for generating a contact force parallel to a first direction between the limiting post 65 and the second limiting groove 63. A first length is greater than a first depth, and the sum of the first length and the second length is less than or equal to a second depth. The first length is the length of the limiting post 65 along the first direction. The first depth is the depth of the second limiting groove 63 along the first direction. The second length is the minimum length formed by the first elastic member 64 after being compressed along the first direction within its elastic deformation range. The second depth is the depth of the first limiting groove 62 along the first direction. The first direction is parallel to the axial direction of the inner casing 2.

[0028] In use, if circumferential positioning of the outer casing 1 and the inner casing 2 is required, the limiting post 65 is pressed inward, compressing the first elastic element 64 so that the limiting post 65 is fully retracted into the first limiting groove 62, thereby facilitating the embedding of the inner casing 2 into the T-shaped annular cavity of the outer casing 1; further, the relative position between the outer casing 1 and the inner casing 2 is adjusted until the first limiting groove 62 and the second limiting groove 63 are precisely aligned; further, the first elastic element 64 rebounds and pushes the limiting post 65 axially into the second limiting groove 63, thereby enabling the limiting post 65 to achieve circumferential positioning of the outer casing 1 and the inner casing 2.

[0029] In this embodiment, the second limiting groove 63 corresponds to the first limiting groove 62, meaning that when the inner casing 2 is fully embedded in the T-shaped annular cavity of the outer casing 1, and the center lines of the outer casing 1 and the inner casing 2 coincide and their axial and radial positions are precisely aligned, the center lines of the first limiting groove 62 and the second limiting groove 63 are collinear. This ensures that the limiting post 65 can smoothly enter the second limiting groove 63 from the first limiting groove 62 under the rebound action of the first elastic element 64, thus completing the circumferential limiting of the outer casing 1 and the inner casing 2.

[0030] In this embodiment, the matching of the limiting post 65 with the first limiting groove 62 and the second limiting groove 63 means that the outer diameter of the limiting post 65 matches the inner diameter of the first limiting groove 62 and the second limiting groove 63. The limiting post 65 can slide smoothly along the axial direction in the first limiting groove 62 without radial loosening. After the limiting post 65 is inserted into the second limiting groove 63, the outer wall of the post is tightly fitted with the inner wall of the groove, with no circumferential gap or only a small gap (e.g., a gap of 50 mil or 100 mil). This can accurately limit the relative circumferential displacement between the outer casing 1 and the inner casing 2, and will not hinder the slight axial and radial deformation of the outer casing 1 and the inner casing 2 caused by thermal expansion, thus taking into account both the limiting stability and the thermal deformation compensation requirements.

[0031] In this embodiment, no restrictions are placed on the shape and structure of the first elastic element 64 (the same applies to the second elastic element 73 described below, which will not be elaborated further), as long as the first elastic element 64 can generate a counterforce parallel to the first direction between the limiting post 65 and the second limiting groove 63. For example, the first elastic element 64 can be an elastic metal sheet, or as... Figure 4 The image shows a spring.

[0032] To facilitate the release of the circumferential limiting effect of the limiting post 65 between the outer casing 1 and the inner casing 2, in one embodiment of this application, such as... Figure 4 As shown, the outer casing 1 is also provided with a disassembly hole 66 corresponding to the limiting post 65. The inner diameter of the disassembly hole 66 is smaller than the inner diameter of the second limiting groove 63.

[0033] In use, if it is necessary to release the circumferential limit between the outer casing 1 and the inner casing 2, a slender tool (e.g., a copper rod or a plastic rod) is inserted into the disassembly hole 66 of the outer casing 1 and pushed inward to push the limiting post 65. The first elastic element 64 is compressed so that the limiting post 65 is completely retracted into the first limiting groove 62 of the inner casing 2, releasing the engagement state between the limiting post 65 and the second limiting groove 63. At this time, the circumferential limit between the outer casing 1 and the inner casing 2 is released, and the outer casing 1 and the inner casing 2 can be separated smoothly to complete the disassembly operation.

[0034] In this embodiment, the correspondence between the disassembly hole 66 and the limiting post 65 means that the disassembly hole 66 is directly opposite the end face of the limiting post 65 facing the disassembly hole 66, ensuring that the slender tool can accurately push the limiting post 65 through the disassembly hole 66 so that the limiting post 65 can smoothly compress the first elastic member 64 to release the limitation.

[0035] It is important to understand that the limiting module proposed in this embodiment does not require the limiting post to form an interference fit with the outer or inner casing. The elastic preload generated by the first elastic element can achieve stable and reliable circumferential limiting between the outer and inner casings. At the same time, the non-interference limiting can reserve sufficient margin for the axial and radial thermal deformation of the outer and inner casings, effectively releasing thermal stress and fundamentally solving the problems of jamming, disassembly difficulties and structural damage caused by rigid interference limiting.

[0036] It is important to note that most current mainstream casing structures employ complex cooling channels (e.g., serpentine channels, porous cooling structures, etc.) machined inside the inner casing. To accommodate these cooling channels, the inner casing must have a relatively thick wall, which not only significantly increases material usage but also leads to uneven thermal stress distribution, affecting the inner casing's ability to coordinate deformation under high-temperature conditions. Furthermore, the machining of these complex internal channels requires extremely high process precision, typically necessitating special machining techniques such as precision casting or deep hole drilling. This results in high machining difficulty, long production cycles, and low yield rates, directly increasing the manufacturing cost of gas turbine casings. Therefore, in one embodiment of this application, the casing structure also includes multiple casing protrusions 3. For example... Figure 1 and Figure 2 As shown, the centerlines of the outer casing 1 and the inner casing 2 coincide. Each casing protrusion 3 is disposed between the outer casing 1 and the inner casing 2, and the casing protrusion 3 is distributed circumferentially around the inner casing 2. Two adjacent casing protrusions 3 form a cooling channel 4 with the inner wall surface of the outer casing 1 and the outer wall surface of the inner casing 2.

[0037] This embodiment replaces the traditional complex serpentine, multi-hole cooling channel design inside the inner casing by setting multiple casing protrusions 3 between the outer casing 1 and the inner casing 2, utilizing adjacent casing protrusions 3, the outer casing 1, and the inner casing 2 to form a cooling channel 4. This casing structure eliminates the need to thicken the inner casing wall, reducing material usage and avoiding uneven thermal stress distribution caused by internal cooling channels, thus improving the deformation coordination of the inner casing under high-temperature conditions. In terms of manufacturing, the casing structure formed by the outer casing 1, inner casing 2, and multiple casing protrusions 3 is relatively simple, eliminating the need for special processes such as precision casting and deep hole drilling, reducing manufacturing difficulty, shortening the production cycle, and increasing yield, fundamentally reducing the manufacturing cost of the casing structure. During use, cooling gas can... Figure 3 , Figures 6 to 8As shown in direction C, the cooling channel 4 formed between the outer casing 1 and the inner casing 2 flows.

[0038] It is important to note that in existing technologies, once the cooling channel is manufactured, its cooling gas flow rate cannot be adjusted. If the cooling gas flow rate does not match the cooling requirements of the gas turbine, the following problems may occur: If the cooling gas flow rate is greater than the cooling requirements of the gas turbine, excessive cooling gas loss will occur, reducing the gas turbine's main airflow share and lowering its power efficiency and output power. If the cooling gas flow rate is less than the cooling requirements of the gas turbine, the heat accumulated in the components requiring cooling cannot be removed in time, causing these components to exceed their temperature limits. Under prolonged high temperatures, creep, ablation, and other problems may occur, threatening the safe operation of the gas turbine. In order to adjust the cooling gas flow rate entering the cooling channel to match the cooling requirements of the gas turbine, in one embodiment of this application, the casing structure also includes an adjustment module, which is disposed in the outer casing 1 or the inner casing 2, and is used to adjust the opening of the cooling channel 4.

[0039] Specifically, the adjustment module can be as follows: Figure 6 As shown, it includes an adjusting ring 71, which is threadedly connected to the outer casing 1 or the inner casing 2 by a plurality of fastening bolts 72.

[0040] When using it, if the cooling air volume needs to be adjusted, change to a different radial width (i.e., such as...). Figure 6 The adjustment ring 71 with the width S shown can be used. It should be clear that if the radial width of the adjustment ring 71 is larger, the opening of the cooling channel 4 inlet is smaller, that is, the cooling air volume is smaller; if the radial width of the adjustment ring 71 is smaller, the opening of the cooling channel 4 inlet is larger, that is, the cooling air volume is larger.

[0041] To eliminate the need for frequent disassembly and replacement of the adjusting ring 71 when adjusting the cooling air volume—that is, to allow different cooling air volumes to be adjusted using the same adjusting ring 71—in one embodiment of this application, the adjusting ring 71 is elastic. And as... Figure 7 As shown, the adjusting ring 71 includes a curved section 711 and a horizontal section 712, such that the radial width of the adjusting ring 71 is positively correlated with the axial compressive force applied to the adjusting ring 71.

[0042] In use, if it is necessary to reduce the cooling air volume, tighten the fastening bolts 72 of the adjusting ring 71 in a diagonal sequence. As the fastening bolts 72 are tightened, the axial compressive force on the adjusting ring 71 gradually increases, and its curved section 711 is axially compressed and elastically deformed radially outward, causing the horizontal section 712 to extend outward synchronously. This increases the overall radial width S of the adjusting ring 71, and the inlet opening of the cooling channel 4 decreases accordingly, ultimately achieving a precise reduction in the cooling air volume. If it is necessary to increase the cooling air volume, loosen the fastening bolts 72 of the adjusting ring 71 in a diagonal sequence. As the fastening bolts 72 are loosened, the axial compressive force on the adjusting ring 71 gradually decreases, and the compressed curved section 711 gradually springs back to its original position under its own elastic force, causing the horizontal section 712 to contract radially inward. This decreases the overall radial width S of the adjusting ring 71, and the inlet opening of the cooling channel 4 increases accordingly, ultimately achieving a precise increase in the cooling air volume.

[0043] In another embodiment of this application, such as Figure 8 As shown, the adjusting ring 71 has a 7-shaped cross-section, and the bolt shank of each fastening bolt 72 moves through the adjusting ring 71. The casing structure also includes a second elastic element 73 corresponding to each fastening bolt 72. Each second elastic element 73 is located between the adjusting ring 71 and the casing, and each second elastic element 73 is used to apply an elastic force to the adjusting ring 71 in a second direction. The second direction is parallel to the axis of the fastening bolt 72 corresponding to the second elastic element 73, and points from the bolt shank of the fastening bolt 72 to the bolt head.

[0044] In use, if it is necessary to reduce the cooling air volume, tighten the fixing bolts 72 of the adjusting ring 71 in a diagonal sequence. As the fixing bolts 72 are tightened, the adjusting ring 71 can overcome the elastic force generated by the second elastic element 73 and move along the axial direction of the inner casing 2 towards the inlet of the cooling channel 4. Since the cross-section of the adjusting ring 71 is shaped like a "7", its radially protruding flange will gradually extend into the inlet area of ​​the cooling channel 4 with the axial displacement. Therefore, the closer the adjusting ring 71 is to the inlet of the cooling channel 4, the smaller the effective flow area of ​​the cooling channel 4, and the cooling air volume is reduced accordingly. If it is necessary to increase the cooling air volume, loosen the fixing bolts 72 of the adjusting ring 71 in a diagonal sequence. As the fixing bolts 72 are loosened, the axial compression of the second elastic element 73 gradually decreases, and its stored elastic potential energy is gradually released. The resulting elastic force pushes the adjusting ring 71 along the axial direction of the inner casing 2 away from the inlet of the cooling channel 4. Since the cross-section of the adjusting ring 71 is shaped like the number 7, its radially protruding flange will gradually exit the inlet area of ​​the cooling channel 4 with the axial displacement, thereby increasing the effective flow area of ​​the cooling channel 4 and ultimately achieving precise adjustment of the cooling air volume.

[0045] In this embodiment, the bolt shank of the fastening bolt 72 movably passes through the adjusting ring 71, meaning that the adjusting ring 71 has a smooth hole rather than a threaded hole. The bolt shank of the fastening bolt 72 can freely pass through this smooth hole, and the bolt head only serves to axially limit the adjusting ring 71; there is no threaded connection between the two. The adjusting ring 71 can slide back and forth along the axis of the bolt shank, thereby achieving continuous adjustment of the axial position under the combined action of the elastic force of the second elastic element 73 and the bolt tightening force.

[0046] The casing structure proposed in this application employs a split outer casing with a C-shaped cross-section, forming a T-shaped annular cavity within it to nest an inner casing. This allows for automatic axial and radial positioning of the inner and outer casings, eliminating the need for numerous bolts for connection and positioning. This reduces the number of parts and assembly steps, lowering manufacturing costs. During maintenance, only the circumferential constraints of the positioning module need to be released for rapid separation of the inner and outer casings. This retains the core advantage of split casings for on-site cylinder opening maintenance, eliminating the need for complete disassembly of the gas turbine rotor, bearing housings, and upstream and downstream piping systems. It allows direct exposure of internal hot-end components, significantly improving maintenance efficiency, effectively shortening gas turbine downtime maintenance cycles, and reducing downtime losses and return-to-factory repair costs.

[0047] Having described the casing structure proposed in the embodiments of this application, the following describes a gas turbine proposed in this application. This gas turbine includes the casing structure described in any of the embodiments above.

[0048] The gas turbine proposed in this application employs a split outer casing with a C-shaped cross-section, forming a T-shaped annular cavity nested within the inner casing. This allows for automatic axial and radial positioning of the inner and outer casings, eliminating the need for numerous bolts for connection and positioning. This reduces the number of parts and assembly steps, lowering manufacturing costs. During maintenance, only the circumferential constraints of the positioning module need to be released for rapid separation of the inner and outer casings. This retains the core advantage of on-site cylinder opening maintenance of the split casing design, eliminating the need for complete disassembly of the gas turbine rotor, bearing housings, and upstream and downstream piping systems. It allows direct exposure of internal hot-end components, significantly improving maintenance efficiency, effectively shortening the gas turbine downtime maintenance cycle, and reducing downtime losses and return-to-factory repair costs.

[0049] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A casing structure, characterized in that, It includes an outer casing (1) and an inner casing (2); both the outer casing (1) and the inner casing (2) are split casings; the cross-section of the outer casing (1) is C-shaped so that the interior of the outer casing (1) forms an annular cavity with a T-shaped cross-section; the inner casing (2) is disposed in the annular cavity; a limiting module is also provided between the outer casing (1) and the inner casing (2), and the limiting module is at least used to limit the circumferential relative displacement between the outer casing (1) and the inner casing (2).

2. The casing structure according to claim 1, characterized in that, The limiting module includes: The first limiting groove (62) is disposed in the inner casing (2); A limiting hole (67) is provided in the outer casing (1); the limiting hole (67) corresponds to the first limiting groove (62), and the inner diameter of the limiting hole (67) is larger than the inner diameter of the first limiting groove (62); Limiting pin (61); the limiting pin (61) is both interference-fitted with the first limiting groove (62) and interference-fitted with the limiting hole (67).

3. The casing structure according to claim 1, characterized in that, The limiting module includes: The first limiting groove (62) is disposed in the inner casing (2); The second limiting groove (63) is disposed in the outer casing (1); the second limiting groove (63) corresponds to the first limiting groove (62); Limiting post (65); the limiting post (65) is adapted to the first limiting groove (62) and the second limiting groove (63) respectively; the first length is greater than the first depth, the first length is the length of the limiting post (65) along the first direction; the first depth is the depth of the second limiting groove (63) along the first direction; the first direction is parallel to the axial direction of the inner casing (2); A first elastic element (64) is disposed between the first limiting groove (62) and the limiting post (65) to generate a counterforce parallel to the first direction between the limiting post (65) and the second limiting groove (63); and the sum of the first length and the second length is less than or equal to the second depth; the second length is the minimum length formed by the first elastic element (64) after being compressed along the first direction within the elastic deformation range; the second depth is the depth of the first limiting groove (62) along the first direction.

4. The casing structure according to claim 3, characterized in that, The outer casing (1) is also provided with a disassembly hole (66) corresponding to the limiting post (65); the inner diameter of the disassembly hole (66) is smaller than the inner diameter of the second limiting groove (63).

5. The casing structure according to any one of claims 1 to 4, characterized in that, It also includes multiple casing protrusions (3); each casing protrusion (3) is disposed between the outer casing (1) and the inner casing (2), and each casing protrusion (3) is distributed around the circumference of the inner casing (2); two adjacent casing protrusions (3) form a cooling channel (4) with the inner wall surface of the outer casing (1) and the outer wall surface of the inner casing (2).

6. The casing structure according to claim 5, characterized in that, It also includes an adjustment module, which is disposed in the outer casing (1) or the inner casing (2) for adjusting the opening of the cooling channel (4).

7. The casing structure according to claim 6, characterized in that, The adjustment module includes an adjustment ring (71), which is threadedly connected to the outer casing (1) or the inner casing (2) by a plurality of fastening bolts (72).

8. The casing structure according to claim 7, characterized in that, The adjusting ring (71) is elastic; and the adjusting ring (71) includes a curved section (711) and a horizontal section (712) such that the radial width of the adjusting ring (71) is positively correlated with the axial compressive force applied to the adjusting ring (71).

9. The casing structure according to claim 7, characterized in that, The cross-section of the adjusting ring (71) is shaped like the number 7, and the bolt shank of each fastening bolt (72) moves through the adjusting ring (71); the casing structure also includes a second elastic element (73) corresponding to each fastening bolt (72); each second elastic element (73) is located between the adjusting ring (71) and the casing, and each second elastic element (73) is used to apply an elastic force along a second direction to the adjusting ring (71); the second direction is parallel to the axis of the fastening bolt (72) corresponding to the second elastic element (73), and is directed from the bolt shank of the fastening bolt (72) to the bolt head.

10. A gas turbine, characterized in that, Includes the casing structure as described in any one of claims 1 to 9.

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