Axial centrifugal compressor for compressed air energy storage

Abstract

The utility model discloses a kind of axial flow centrifugal compressor for compressed air energy storage, it is related to energy storage technical field, comprising: axial flow section, centrifugal section and main shaft;The axial flow section has casing and the axial flow rotor in the casing, the centrifugal section has volute and the centrifugal rotor in the volute, the casing is connected with the volute;The axial flow rotor is connected with the one end of the main shaft by fastener, the centrifugal rotor is sleeved on the main shaft, the upstream end of the centrifugal rotor is supported on the boss of the main shaft the downstream end of the centrifugal rotor is detachably connected with the main shaft by connecting structure.The utility model technical scheme, axial flow rotor and centrifugal rotor are respectively set as detachably connected with main shaft, so that axial flow rotor, centrifugal rotor and main shaft can be separately produced, for large flow, high pressure ratio compressor, independent production facilitates each part manufacturing.

Description

Technical Field

[0001] This utility model relates to the field of energy storage technology, specifically to an axial-flow centrifugal compressor for compressed air energy storage. Background Technology

[0002] Compressed air energy storage (CAES) is a large-scale energy storage technology that uses a compressor to convert electrical energy into the potential energy of compressed air for storage. When needed, the compressed air is released to drive a turbine to generate electricity, thus achieving energy recycling.

[0003] Compressors used for compressed air energy storage include axial compressors and centrifugal compressors. Axial compressors have an axial airflow pattern, with similar circumferential velocities before and after the rotor blades. This results in a lower theoretical energy head, leading to insufficient single-stage pressure ratio. To achieve a higher pressure ratio, multiple axial compressors need to be connected in series, which is limited by rotor length. However, axial compressors also have advantages: lower streamline curvature and shorter flow channel length, resulting in relatively lower flow losses. While centrifugal compressors can achieve higher energy output, their energy efficiency is lower than that of axial compressors due to flow losses and leakage. Centrifugal compressors have a larger streamline curvature and longer flow channel length, leading to significant secondary flow losses.

[0004] In addition, in practical applications, there exists an "axial-centrifugal combined compressor," which combines the advantages of both: the axial stage achieves high flow rate in the low-pressure section, while the centrifugal stage increases the pressure ratio in the high-pressure section, balancing efficiency and high-pressure requirements. For example, Chinese patent document CN106939832A discloses an axial-centrifugal integral impeller-type combined compression system, in which the integral impeller includes several axial blades, centrifugal blades, and a support disk. The axial blades are fixedly located upstream of the support disk, and the centrifugal blades are fixedly located downstream of the support disk. This technical solution is suitable for small gas turbine engines, where the rotor and impeller outer ring are each composed of a single part, simplifying the compression system structure.

[0005] However, the impellers in large-scale energy storage systems are often quite large. When machining them as a whole, whether using casting, forging, or machining methods, it is difficult to ensure machining accuracy and product quality. Therefore, for compressors requiring high flow rates and high pressure ratios, designing the rotor and impeller outer ring as a single component is practically impossible. Utility Model Content

[0006] In view of this, the present invention provides an axial-centrifugal compressor for compressed air energy storage, in order to solve the problem that the structure of the existing axial-centrifugal combined compressor is not suitable for compressors with large flow rates and high pressure ratios.

[0007] This utility model provides an axial-flow centrifugal compressor for compressed air energy storage, comprising: an axial-flow section, a centrifugal section, and a main shaft;

[0008] The axial flow section has a casing and an axial flow rotor located within the casing, and the centrifugal section has a volute and a centrifugal rotor located within the volute, with the casing connected to the volute.

[0009] The axial rotor is connected to one end of the main shaft by fasteners. The centrifugal rotor is sleeved on the main shaft. The upstream end of the centrifugal rotor is supported on the boss of the main shaft. The downstream end of the centrifugal rotor is detachably connected to the main shaft by a connecting structure.

[0010] This invention utilizes a combination of axial and centrifugal sections to fully leverage the advantages of both. In the axial section, the rotation of the axial rotor within the casing enables the intake and initial compression of a large flow rate of gas. In the centrifugal section, the centrifugal rotor further compresses the gas within the volute to meet the compressed air pressure requirements of the energy storage system. This combination allows the compressor to achieve a high compression ratio while ensuring a large intake flow rate, thereby improving the energy storage efficiency of the compressed air energy storage system.

[0011] The present invention provides a detachable connection between the axial rotor and the centrifugal rotor and the main shaft, allowing the axial rotor, centrifugal rotor and main shaft to be manufactured separately. For high-flow, high-pressure-ratio compressors, independent production facilitates the manufacturing of each part.

[0012] Optionally, a bearing housing is provided between the axial rotor and the centrifugal rotor, the bearing housing is connected to the volute and / or the casing, a bearing cavity is formed between the bearing housing and the main shaft, a bearing is provided in the bearing cavity, and the bearing is sleeved on the main shaft.

[0013] Optionally, the centrifugal rotor has an annular groove on one end face facing the bearing housing, and a locking seal is detachably connected to the bearing housing. The locking seal has a first extension extending into the annular groove, and a labyrinth seal is provided between the first extension and the inner wall of the annular groove.

[0014] Optionally, the inner wall of the annular groove has a toothed component, and the first extension of the locking seal has a sealing surface that mates with the toothed component.

[0015] In the above scheme, the rigid structure of the grate can withstand a certain degree of vibration and displacement, while the sealing surface can be adaptively adjusted according to the shape of the grate to maintain good sealing contact. With this configuration, when the compressor starts, stops, or its operating conditions change, the centrifugal rotor may vibrate and displace. At this time, the fit between the grate and the sealing surface can maintain the sealing performance, prevent seal failure caused by vibration, and ensure reliable operation of the compressor.

[0016] Optionally, a baffle ring is detachably connected to the bearing housing, and the baffle ring is clearance-fitted with the end of the annular groove of the centrifugal rotor.

[0017] Optionally, the locking seal has a second extension extending into the bearing housing and located downstream of the bearing. The spindle has a support ring with a sealing material between the support ring and the second extension. The sealing material is circumferentially slidingly fitted with the support ring and / or the locking seal.

[0018] In the above design, the support ring provides stable support for the sealing material, ensuring it maintains a good seal even under centrifugal force, vibration, and temperature changes generated by the high-speed rotation of the main shaft. This design also reduces the impact of vibration on the sealing material during compressor start-up and shutdown, preventing displacement or damage and ensuring unaffected sealing performance.

[0019] Optionally, the sealing material is graphite. Graphite has good flexibility and self-lubricating properties. As a sealing material, it can fit tightly between the support ring and the locking seal, effectively preventing gas leakage.

[0020] Optionally, upstream of the bearing, there are multiple sealing structures spaced apart between the bearing housing and the main shaft.

[0021] Optionally, the axial rotor is connected to a rear journal by fasteners. The rear journal has a cavity for inserting into the main shaft. The cavity and the main shaft are connected by a spline. After the main shaft is inserted into the cavity, a self-locking nut is connected to the end of the main shaft.

[0022] Optionally, the connection structure includes a disc spring and an anti-loosening sleeve, the disc spring and the anti-loosening sleeve being sequentially sleeved on the main shaft, the disc spring being clearance-fitted with the main shaft, the anti-loosening sleeve being fixedly connected to the main shaft, the anti-loosening sleeve abutting against the disc spring, and the disc spring abutting against the downstream end of the centrifugal rotor.

[0023] In the above scheme, the disc spring is sleeved on the main shaft and abuts against the end of the centrifugal rotor away from the axial rotor. It applies axial preload to the centrifugal rotor through its own elastic deformation. During the operation of the axial centrifugal compressor, the high-speed rotation of the centrifugal rotor will generate axial force and vibration. The preload of the disc spring can ensure that the centrifugal rotor maintains a stable position in the axial direction, avoiding collisions with other components or affecting the sealing performance due to axial displacement.

[0024] In addition, disc springs possess excellent elastic properties, enabling them to absorb and buffer vibration and impact energy generated during compressor operation. When the compressor vibrates due to airflow pulsation, mechanical imbalance, or other reasons, the disc springs convert the vibration energy into elastic potential energy through their own compression and rebound, thereby reducing the impact of vibration on the centrifugal rotor and other components. This helps reduce noise during equipment operation, extend the equipment's service life, and improve its reliability.

[0025] Optionally, a limiting key is connected to the spindle, the limiting key abuts against the end of the disc spring near the anti-loosening sleeve, and the end of the anti-loosening sleeve near the disc spring has a limiting groove for embedding the limiting key.

[0026] In the above solution, the limiting key is connected to the main shaft and abuts against the disc spring, while also being embedded in the limiting groove of the anti-loosening sleeve, providing precise axial positioning for the disc spring. This ensures that the disc spring is fixed in position on the main shaft, preventing it from moving axially. Furthermore, the cooperation between the limiting key and the limiting groove further enhances the anti-loosening effect. Specifically, during long-term operation of the compressor, vibration and centrifugal force may cause the anti-loosening sleeve to gradually loosen, while the presence of the limiting key greatly reduces this risk. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 A front sectional view of an axial-flow centrifugal compressor provided for an embodiment of this utility model;

[0029] Figure 2 for Figure 1 A magnified view of a portion of region A in the middle;

[0030] Figure 3 for Figure 2 3D sectional view of the middle baffle ring;

[0031] Figure 4 for Figure 1 A magnified view of a portion of region B in the middle;

[0032] Figure 5 for Figure 1 A magnified view of a portion of region C in the middle;

[0033] Figure 6 A front sectional view of another axial-flow centrifugal compressor provided in an embodiment of this utility model;

[0034] Figure 7 for Figure 6 A magnified view of a portion of region D in the middle;

[0035] Figure 8 A perspective view of the combination of moving and stationary blades inside the axial section of an axial centrifugal compressor provided in an embodiment of this utility model.

[0036] Figure 9 for Figure 8 A three-dimensional view of a central axial flow rotor;

[0037] Figure 10 for Figure 9 A magnified view of a portion of region E in the middle;

[0038] Explanation of reference numerals in the attached figures:

[0039] 1. Main shaft; 2. Casing; 3. Axial rotor; 4. Volute; 5. Centrifugal rotor; 6. Locking seal; 7. Annular groove; 8. First extension section; 9. Grate; 10. Support ring; 11. Sealing material; 12. Baffle ring; 13. Disc spring; 14. Anti-loosening sleeve; 15. Limit key; 16. Second extension section; 17. Connecting section; 18. Adjustable stationary blade; 19. Non-adjustable stationary blade; 20. Moving blade; 21. Tenon; 22. Mortise; 23. Inner rectifier ring; 24. Outer rectifier ring; 25. Air vent; 26. Rear journal; 27. Self-locking nut; 28. Bearing; 29. ​​Bearing housing; 30. First oil baffle ring; 31. Third extension section; 32. Second oil baffle ring; 33. Fourth extension section; 34. Support section; 35. Graphite seal. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0041] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model 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, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0042] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0043] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0044] Example 1

[0045] like Figure 1 The image shows a specific embodiment of the axial-centrifugal compressor for compressed air energy storage provided in this example, comprising: an axial section, a centrifugal section, and a main shaft 1. The axial section has a casing 2 and an axial rotor 3 located within the casing 2, and the centrifugal section has a volute 4 and a centrifugal rotor 5 located within the volute 4. The casing 2 is connected to the volute 4. It should be noted that the casing 2 has various structural forms; it can be composed of several cylindrical sections connected sequentially, or it can be a cylinder divided into two halves along the axial direction.

[0046] like Figure 1 As shown, in this embodiment, the axial rotor 3 is connected to one end of the main shaft 1 by fasteners, the centrifugal rotor 5 is sleeved on the main shaft 1, the upstream end of the centrifugal rotor 5 is supported on a boss on the main shaft 1, and the downstream end of the centrifugal rotor 5 is detachably connected to the main shaft 1 through a connecting structure. That is, in this embodiment, the main shaft 1 has a boss for supporting the centrifugal rotor 5, one end of the centrifugal rotor 5 is supported on this boss, and the other end is locked by the connecting structure.

[0047] It should be noted that, in this embodiment, "upstream" refers to the direction of air intake in the compressor, and "downstream" refers to the direction of air discharge in the compressed air system.

[0048] This embodiment of the technical solution fully leverages the advantages of both axial and centrifugal sections through a combined design. In the axial section, the rotation of the axial rotor 3 within the casing 2 enables the intake and initial compression of a large flow rate of gas. In the centrifugal section, the centrifugal rotor 5 further compresses the gas within the volute 4 to meet the compressed air pressure requirements of the energy storage system. This combination allows the entire compressor to achieve a high compression ratio while ensuring a large flow rate of air intake, thereby improving the energy storage efficiency of the compressed air energy storage system.

[0049] In this embodiment, the axial rotor 3 and the centrifugal rotor 5 are detachably connected to the main shaft 1, so that the axial rotor 3, the centrifugal rotor 5 and the main shaft 1 can be produced independently. For high flow rate and high pressure ratio compressors, independent production facilitates the manufacturing of each part.

[0050] like Figure 1 As shown, in this embodiment, a bearing housing 29 is provided between the axial rotor 3 and the centrifugal rotor 5. The bearing housing 29 is connected to the casing 2, and a bearing 28 cavity is formed between the bearing housing 29 and the main shaft 1. A bearing 28 is provided in the bearing 28 cavity and is used to be fitted onto the main shaft 1, thereby allowing the main shaft 1 to rotate within the bearing 28. The bearing housing 29 and the bearing 28 within it provide a stable support structure for the main shaft 1 and precisely limit its radial displacement. Of course, the above description is not limiting. In some alternative embodiments, the bearing housing 29 may be integrally formed with the casing 2 or may be connected to the volute 4.

[0051] like Figure 1 As shown, in this embodiment, the bearing housing 29 is provided with an air passage. The inlet of the air passage is adapted to connect to high-pressure gas, and the outlet of the air passage is connected to the bearing cavity 28. The air passage ensures pressure balance inside and outside the bearing cavity 28, thereby guaranteeing a sealing effect.

[0052] like Figure 1 , Figure 2 As shown, in the axial-flow centrifugal compressor provided in this embodiment, the centrifugal rotor 5 has an annular groove 7 on the end face facing the bearing housing 29. A locking seal 6 is detachably connected to the bearing housing 29. The locking seal 6 has a first extension 8 extending into the annular groove 7, and a labyrinth seal is formed between the first extension 8 and the inner wall of the annular groove 7. Specifically, the inner wall of the annular groove 7 has a toothed member 9, and the first extension 8 of the locking seal 6 has a sealing surface that mates with the toothed member 9.

[0053] This labyrinth seal structure exhibits good adaptability to the vibrations and displacements generated by the centrifugal rotor 5 during high-speed rotation. Because the grate teeth 9 are not tightly fitted to the sealing surface, but rather have a certain gap, the seal structure can still maintain good sealing performance even when the centrifugal rotor 5 experiences minor displacement due to vibration or other reasons. Even when the compressor starts up, stops, or its operating conditions change, causing increased vibration of the centrifugal rotor 5, the labyrinth seal will not fail due to minor displacement, ensuring the reliability of the seal and guaranteeing stable compressor operation.

[0054] Of course, the above description is not limiting. In some alternative embodiments, a toothed part 9 may be provided on the first extension 8 of the locking seal 6, and a sealing surface may be provided on the inner wall of the annular groove 7 accordingly.

[0055] like Figure 2 As shown, in this embodiment, the locking seal 6 has an annular body with a variable diameter section. The smaller diameter of this variable diameter section serves as the first extension section 8, which mates with the centrifugal rotor 5. The larger diameter section serves as the second extension section 16, which extends into the inner surface of the bearing housing 29. A rubber sealing ring is provided between the second extension section 16 and the inner surface of the bearing housing 29 for sealing. The annular body of the locking seal 6 has a connecting section 17 extending radially outward. The connecting section 17 is fastened to the end of the structure of the casing 2 that extends into the volute 4 by fasteners.

[0056] In the above embodiment, the variable diameter design of the locking seal 6 allows the first extension 8 to mate with the centrifugal rotor 5, and the second extension 16 to mate with the bearing housing 29. This segmented fit provides a better foundation for sealing. Simultaneously, a rubber sealing ring is provided between the second extension 16 and the bearing housing 29 for gap sealing, further enhancing the sealing effect. During the operation of the axial centrifugal compressor, there is a risk of high-pressure gas leakage. This sealing structure effectively prevents gas leakage from the connection between the locking seal 6 and the bearing housing 29 and the centrifugal rotor 5, ensuring stable internal pressure of the compressor and improving compression efficiency.

[0057] like Figure 2 As shown, in this embodiment, the second extension 16 of the locking seal 6 extends into the bearing housing 29 and is located downstream of the bearing 28. The main shaft 1 has a support ring 10, and a sealing material 11 is provided between the support ring 10 and the second extension 16. The sealing material 11 and the locking seal 6 are in circumferential sliding fit.

[0058] In the above embodiment, the support ring 10 and the sealing material 11 work together to adapt to the complex working conditions of the main shaft 1 during high-speed rotation. The support ring 10 provides stable support for the sealing material 11, ensuring that it maintains a good sealing state even under the centrifugal force, vibration, and temperature changes generated by the high-speed rotation of the main shaft 1. With this configuration, during the compressor's start-up and shutdown processes, the change in the main shaft 1's rotational speed causes vibration. The support ring 10 can reduce the impact of vibration on the sealing material 11, preventing displacement or damage to the sealing material 11 and ensuring that the sealing performance is not affected.

[0059] Of course, the above description is not limiting. In some alternative embodiments, the sealing material 11 may also slide with the support ring 10, or the sealing material 11 may slide circumferentially with both the support ring 10 and the locking seal 6.

[0060] like Figure 2 As shown, in this embodiment, the support ring 10 is a hollow ring with an opening on one side. This configuration enables the support ring 10 to have radial elastic deformation capability, thereby improving the elastic support for the sealing material 11.

[0061] It should be noted that in this embodiment, the sealing material 11 is graphite. Graphite has good flexibility and self-lubricating properties. As the sealing material 11, it can fit tightly between the support ring 10 and the locking seal 6, effectively preventing gas leakage.

[0062] Of course, the above description is not limiting. In some alternative embodiments, the sealing material 11 may also be other conventional materials.

[0063] like Figure 2 As shown, in this embodiment, a baffle ring 12 is detachably connected to the bearing housing 29, and the baffle ring 12 is clearance-fitted with the end of the annular groove 7 of the centrifugal rotor 5. The baffle ring 12 allows the fluid to flow in a specific direction, and the clearance fit between the baffle ring 12 and the end of the annular groove 7 can, to a certain extent, prevent fluid from leaking directly from the end of the annular groove 7. By blocking and guiding the fluid with the baffle ring 12, direct impact and pressure from the fluid on the locking seal 6 can be avoided, reducing the working load on the seal.

[0064] like Figure 2 , Figure 3 As shown in this embodiment, the baffle ring 12 has no top surface on the side near the centrifugal impeller, which facilitates installation.

[0065] like Figure 1 , Figure 4As shown, in this embodiment, upstream of the bearing 28, there are multiple sealing structures spaced apart between the bearing housing 29 and the main shaft 1. Specifically, as... Figure 1 As shown, a first oil baffle ring 30 is sandwiched between the axial rotor 3 and the rear journal 26. The outer circumferential surface of the first oil baffle ring 30 has a plurality of serrated members 9. The bearing seat 29 has a third extension section 31 extending to the outer ring of the first oil baffle ring 30. The third extension section 31 has a mating surface that mates with the serrated members 9 of the first oil baffle ring 30.

[0066] like Figure 4 As shown, a second oil baffle ring 32 is fitted on the rear journal 26 at the upstream position of the bearing 28. The outer circumferential surface of the second oil baffle ring 32 has a plurality of serrated members 9. The bearing seat 29 has a fourth extension section 33 extending to the outer circumference of the second oil baffle ring 32. The fourth extension section 33 has a mating surface that mates with the serrated members 9 of the second oil baffle ring 32.

[0067] like Figure 4 As shown, the outer circumferential surface of the second oil baffle ring 32 also has a support section 34 near the bearing 28. A graphite seal 35 is provided on the support section 34, and the graphite seal 35 and the bearing seat 29 are in circumferential sliding fit.

[0068] like Figure 1 , Figure 5 As shown, in this embodiment, the connection structure includes a disc spring 13 and an anti-loosening sleeve 14. The disc spring 13 and the anti-loosening sleeve 14 are sequentially sleeved on the main shaft 1. The disc spring 13 is clearance-fitted with the main shaft 1. The anti-loosening sleeve 14 is fixedly connected to the main shaft 1. The anti-loosening sleeve 14 abuts against the disc spring 13. The disc spring 13 abuts against the end of the centrifugal rotor 5 away from the axial rotor 3.

[0069] In the above embodiment, the disc spring 13 is sleeved on the main shaft 1 and abuts against the end of the centrifugal rotor 5 away from the axial rotor 3, applying axial preload to the centrifugal rotor 5 through its own elastic deformation. During the operation of the axial centrifugal compressor, the high-speed rotation of the centrifugal rotor 5 generates axial force and vibration. The preload of the disc spring 13 ensures that the centrifugal rotor 5 maintains a stable position in the axial direction, avoiding collisions with other components or affecting the sealing performance due to axial displacement.

[0070] In addition, the disc spring 13 has excellent elastic properties, which can absorb and buffer the vibration and impact energy generated during compressor operation. When the compressor vibrates due to airflow pulsation, mechanical imbalance, or other reasons, the disc spring 13 converts the vibration energy into elastic potential energy through its own compression and rebound, thereby reducing the impact of vibration on the centrifugal rotor 5 and other components. This helps to reduce noise during equipment operation, extend the service life of the equipment, and improve the reliability of the equipment.

[0071] like Figure 5 As shown, in this embodiment, a limiting key 15 is connected to the main shaft 1. The limiting key 15 abuts against the end of the disc spring 13 near the anti-loosening sleeve 14. The end of the anti-loosening sleeve 14 near the disc spring 13 has a limiting groove for embedding the limiting key 15.

[0072] In the above embodiment, the limiting key 15 is connected to the main shaft 1 and abuts against the disc spring 13, while also being embedded in the limiting groove of the anti-loosening sleeve 14, providing precise axial positioning for the disc spring 13. This ensures that the disc spring 13 is fixed in position on the main shaft 1, preventing it from moving axially. Furthermore, the cooperation between the limiting key 15 and the limiting groove further enhances the anti-loosening effect. Specifically, during long-term operation of the compressor, vibration and centrifugal force may cause the anti-loosening sleeve 14 to gradually loosen, while the presence of the limiting key 15 greatly reduces this risk.

[0073] Of course, the above description is not limiting. In some embodiments, the connection structure between the downstream end of the centrifugal rotor 5 and the main shaft 1 may also take other forms.

[0074] Example 2

[0075] like Figure 6 , Figure 7 As shown, in this embodiment, the connection structure between the downstream end of the centrifugal rotor 5 and the main shaft 1 differs from that in Embodiment 1. Specifically, in this embodiment, after the centrifugal rotor 5 is sleeved on the main shaft 1, it abuts against the downstream end of the centrifugal rotor 5 through an axial abutment member, thereby achieving detachable installation of the centrifugal rotor 5 and the main shaft 1. Furthermore, the axial abutment member and the end of the centrifugal rotor 5 can be fixedly connected by fasteners.

[0076] like Figure 6As shown, in this embodiment, the downstream end of the axial rotor 3 is connected to a rear journal 26 via fasteners. The main shaft 1 and the rear journal 26 are not integrally formed. That is, the rear journal 26 and the main shaft 1 are detachably connected. Specifically, the rear journal 26 has a cavity with an internal spline, and the main shaft 1 has an external spline. After the main shaft 1 is inserted into the cavity of the rear journal 26, the internal and external splines cooperate to form a circumferential limit. The end of the main shaft 1 has a self-locking nut 27, and a baffle is provided between the self-locking nut 27 and the inner step of the cavity. The self-locking nut 27 provides axial limit for the main shaft 1.

[0077] like Figure 8 As shown, in some embodiments, the axial flow section further includes a stator fixedly connected to the casing 2 and kept stationary. The stator includes adjustable stator blades 18 and non-adjustable stator blades 19. The first 1-3 stages are adjustable stator blades 18 (the specific number of the first 1-3 stages needs to be determined based on the output pressure of the axial flow section; it may be one stage, or it may be one and two stages, or it may be one, two and three stages), while the subsequent stages are non-adjustable stator blades.

[0078] like Figure 9 , Figure 10 As shown, in this embodiment, the axial flow device has multiple stages, and adjacent stages of the working impellers are connected by an overlapping fit of the impeller discs. This connection method facilitates the installation and disassembly of the working impellers. Each stage of the working impeller consists of multiple moving blades 20, and each moving blade 20 is installed by a dovetail tenon 21 and a tenon 22 of the impeller disc with a clearance fit.

[0079] like Figure 8 In the axial flow section, a rectifier ring is provided between adjacent two-stage impellers. This rectifier ring includes an inner rectifier ring 23, an outer rectifier ring 24, and stationary blades. The lower end of the stationary blades is fixed to the inner rectifier ring 23 by welding, while the upper end is detachably connected to the outer rectifier ring 24 by plugging. The outer rectifier ring 24 is provided with air ducts 25, through which high-pressure gas is drawn out and used where needed, such as at the gas seal. The air ducts 25 are evenly distributed around the circumference of the entire casing 2 to ensure uniform air intake.

[0080] Gas compression principle: The axial section rotates within the casing 2 via the axial rotor 3, achieving the intake and initial compression of a large flow of gas; the centrifugal section further compresses the gas within the volute 4 via the centrifugal rotor 5, meeting the energy storage system's requirements for compressed air pressure. The combination of the two ensures a large flow of gas intake and a high compression ratio, thereby improving energy storage efficiency.

[0081] Gas flow stability: The main shaft 1 is connected in sequence to the axial rotor 3 and the centrifugal rotor 5 to ensure that the gas flows continuously and stably between the two sections, reducing energy loss and efficiency reduction.

[0082] Sealing principle: A sealing structure is set at the upstream end of the centrifugal rotor 5, especially the sealing cooperation between the locking seal 6 and the centrifugal rotor 5, the main shaft 1, and the casing 2, which effectively prevents compressed gas leakage at the transition between the axial and centrifugal sections. Multiple sealing structures, such as labyrinth seals and rubber sealing rings, work together to maintain the internal pressure of the compressor and improve compression efficiency.

[0083] Centrifugal rotor 5 connection and stabilization principle: The downstream end of the centrifugal rotor 5 is detachably connected to the main shaft 1 through a connecting structure (such as disc spring 13, anti-loosening sleeve 14, etc.). Disc spring 13 provides axial preload to ensure the axial stability of the centrifugal rotor 5 and absorb vibration and impact energy; the limiting key 15 cooperates with the limiting groove of the anti-loosening sleeve 14 to prevent the disc spring 13 and the anti-loosening sleeve 14 from moving axially, thereby enhancing connection stability.

[0084] It should be noted that although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the present invention.

Claims

1. An axial-flow centrifugal compressor for compressed air energy storage, characterized in that, include: Axial flow section, centrifugal section and main shaft (1); The axial flow section has a casing (2) and an axial flow rotor (3) located inside the casing (2), and the centrifugal section has a volute (4) and a centrifugal rotor (5) located inside the volute (4), and the casing (2) is connected to the volute (4); The axial rotor (3) is connected to one end of the main shaft (1) by fasteners. The centrifugal rotor (5) is sleeved on the main shaft (1). The upstream end of the centrifugal rotor (5) is supported on the boss of the main shaft (1). The downstream end of the centrifugal rotor (5) is detachably connected to the main shaft (1) through a connecting structure.

2. The axial-flow centrifugal compressor for compressed air energy storage according to claim 1, characterized in that, The axial rotor (3) and the centrifugal rotor (5) have a bearing housing (29), the bearing housing (29) is connected to the volute (4) and / or the casing (2), the bearing housing (29) and the main shaft (1) form a bearing (28) cavity, the bearing (28) cavity is provided with a bearing (28), and the bearing (28) is sleeved on the main shaft (1).

3. The axial-flow centrifugal compressor for compressed air energy storage according to claim 2, characterized in that, The centrifugal rotor (5) has an annular groove (7) on one end face facing the bearing housing (29). A locking seal (6) is detachably connected to the bearing housing (29). The locking seal (6) has a first extension (8) extending into the annular groove (7). A labyrinth seal is provided between the first extension (8) and the inner wall of the annular groove (7).

4. The axial-flow centrifugal compressor for compressed air energy storage according to claim 3, characterized in that, The inner wall of the annular groove (7) has a toothed part (9), and the first extension (8) of the locking seal (6) has a sealing surface that mates with the toothed part (9).

5. The axial-flow centrifugal compressor for compressed air energy storage according to claim 4, characterized in that, A baffle ring (12) is detachably connected to the bearing housing (29), and the baffle ring (12) is clearance-fitted with the end of the annular groove (7) of the centrifugal rotor (5).

6. The axial-flow centrifugal compressor for compressed air energy storage according to claim 3, characterized in that, The locking seal (6) has a second extension (16) that extends into the bearing housing (29) and is located downstream of the bearing (28). The spindle (1) has a support ring (10) with a sealing material (11) between the support ring (10) and the second extension (16). The sealing material (11) is circumferentially slidingly fitted with the support ring (10) and / or the locking seal (6).

7. The axial-flow centrifugal compressor for compressed air energy storage according to claim 2, characterized in that, Upstream of the bearing (28), there are multiple sealing structures spaced apart between the bearing housing (29) and the main shaft (1).

8. The axial-flow centrifugal compressor for compressed air energy storage according to any one of claims 1-7, characterized in that, The axial rotor (3) is connected to a rear journal (26) by fasteners. The rear journal (26) has a cavity for inserting into the main shaft (1). The cavity and the main shaft (1) are connected by a spline. After the main shaft (1) is inserted into the cavity, a self-locking nut (27) is connected to the end of the main shaft (1).

9. The axial-flow centrifugal compressor for compressed air energy storage according to any one of claims 1-7, characterized in that, The connection structure includes a disc spring (13) and an anti-loosening sleeve (14). The disc spring (13) and the anti-loosening sleeve (14) are sequentially sleeved on the main shaft (1). The disc spring (13) is clearance-fitted with the main shaft (1). The anti-loosening sleeve (14) is fixedly connected to the main shaft (1). The anti-loosening sleeve (14) abuts against the disc spring (13). The disc spring (13) abuts against the downstream end of the centrifugal rotor (5).

10. The axial-flow centrifugal compressor for compressed air energy storage according to claim 9, characterized in that, A limiting key (15) is connected to the main shaft (1). The limiting key (15) abuts against the end of the disc spring (13) near the anti-loosening sleeve (14). The end of the anti-loosening sleeve (14) near the disc spring (13) has a limiting groove for embedding the limiting key (15).

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