Centrifugal compressor casing adapted to ultra-high pressure ratio and centrifugal compressor having the same

Abstract

The present invention discloses a centrifugal compressor casing adapted to a super-high pressure ratio and a centrifugal compressor having the same, including: a casing integrated body integrating the existing inlet casing, adapter casing, impeller shroud and diffuser casing, and multiple inlet guide vanes integrally designed with the casing integrated body. The multiple inlet guide vanes are sequentially and spacedly connected along the circumferential direction of the casing integrated body to the inner wall surface of the inlet air flow passage in the casing integrated body. A plurality of gas circulation channels are sequentially and spacedly arranged along the circumferential direction inside the inner wall surface of the inlet air flow passage. The plurality of gas circulation channels extend along the inlet air axis, and both ends of each gas circulation channel penetrate the inner wall surface of the casing integrated body to communicate with the inlet air flow passage, thereby forming a gas self-circulation structure. The structure of the present invention maximally realizes the integration of the compressor stator parts, and at the same time can maximally improve the stability of the inlet air flow in the working state. Moreover, the structure is simple, the working stability is high, the stable working margin of the compressor can be effectively improved, and surging can be prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of compressor casings, and in particular, to a centrifugal compressor casing adapted to ultra-high pressure ratios. In addition, the present invention also relates to a centrifugal compressor including the above-mentioned centrifugal compressor casing adapted to ultra-high pressure ratios. Background Art

[0002] For ultra-high pressure ratio (generally a single-stage centrifugal pressure ratio of the order of 15 and a temperature rise of more than 400 °C) centrifugal compressors, the stator parts are generally designed according to traditional structures, which usually include an inlet casing (forming an inlet passage), a transition casing (transitioning the impeller shroud and the inlet casing and installing inlet guide vanes), inlet guide vanes (guiding the inlet air flow), an impeller shroud (forming the corresponding flow passage for the centrifugal impeller), a diffuser casing (installing a radial diffuser and an axial diffuser), a diffuser structure (usually including radial and axial diffuser blades, cover plates, etc.).

[0003] Ultra-high pressure ratio compressors need to adopt stability augmentation measures to ensure their stable operating margin and prevent surging. Usually, methods such as adjustable inlet guide vanes (requiring a supporting guide vane adjustment system) or intermediate bleed (requiring a supporting bleed stability augmentation system) are used, and they are generally essential.

[0004] In the prior art, due to the relatively large increase in the pressure ratio of ultra-high pressure ratio centrifugal compressors, the temperature gradient increases significantly, and the comprehensive design requirements for individual functional components such as strength, stiffness, and thermal deformation are relatively high. Therefore, when designing the compressor casing in the prior art, multiple parts are generally used to ensure respectively, resulting in a relatively large number of stator parts, a relatively heavy weight, and a relatively high processing cost for ultra-high pressure ratio centrifugal compressors; the assembly and disassembly processes of the compressor are relatively complex, and the installation, disassembly, and maintenance costs are high; in order to meet the requirements of ultra-high pressure ratios, a guide vane adjustment system or a bleed stability augmentation system needs to be configured, which will additionally increase the weight and at the same time increase the processing and assembly costs of accessories and pipelines. At the same time, the problem of insufficient stable operating margin caused by the large increase in the pressure ratio also needs to be solved by a supporting system; the inlet and outlet of the impeller shroud are continuous, and it is difficult to control the inlet deformation and clearance. Summary of the Invention

[0005] The present invention provides a centrifugal compressor casing adapted to ultra-high pressure ratios and a centrifugal compressor having the same, so as to solve the technical problems existing in the structure of the existing centrifugal compressor, such as a relatively large number of parts, a relatively heavy weight, a relatively high processing cost, an additional increase in weight, and an increase in the processing and assembly costs of accessories and pipelines.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A centrifugal compressor casing adapted to a super-high pressure ratio, comprising: a casing integrated body integrating the existing intake casing, adapter casing, impeller shroud and diffuser casing, and multiple inlet guide vanes integrally designed with the casing integrated body, the multiple inlet guide vanes being sequentially and spacedly connected to the inner wall surface of the intake air flow passage in the casing integrated body along the circumferential direction of the casing integrated body; multiple gas circulation channels are also provided in the inner wall surface of the intake air flow passage of the casing integrated body at intervals along the circumferential direction, the multiple gas circulation channels extend along the intake air axis, and both ends of each gas circulation channel penetrate through the inner wall surface of the casing integrated body to communicate with the intake air flow passage, thereby forming a gas self-circulation structure.

[0008] Further, an annular concave gas collecting cavity is provided on the inner wall surface of the intake air flow passage, the gas collecting cavity is close to the impeller tip of the centrifugal impeller to be installed in the intake air flow passage, and the gas collecting cavity communicates with the intake end of the gas circulation channel to form an air inlet, and the outlet end of the gas circulation channel extends to be close to the intake port of the intake air flow passage.

[0009] Further, the axial width of the gas collecting cavity is 1 mm to 2 mm; the radial width of the air outlet of the outlet end of the gas circulation channel is 2 mm to 3 mm.

[0010] Further, the casing integrated body includes a hollow cylindrical casing body and an internal flow passage ring, and multiple internal rib plates for connection; the internal flow passage ring is located inside the casing body, and the multiple internal rib plates are sequentially and spacedly arranged along the circumferential direction and are connected between the inner wall surface of the casing body and the outer wall surface of the internal flow passage ring, so that multiple gas circulation channels are formed at intervals along the circumferential direction between the inner wall surface of the casing body and the outer wall surface of the internal flow passage ring; the inner channel of the internal flow passage ring forms the intake air flow passage, and multiple inlet guide vanes are sequentially and spacedly connected to the inner wall surface of the internal flow passage ring along the circumferential direction.

[0011] Further, the inner wall surface of the casing body is recessed to form a gas collecting cavity; the first ends of the internal flow passage ring and the internal rib plates close to the gas collecting cavity are flush, and the first ends of the two form the outer side wall of the gas collecting cavity; the second ends of the internal rib plates extend to be close to the intake port of the casing body, and the second end of the internal flow passage ring extends axially close to the second end of the internal rib plate to form an air outlet of the gas circulation channel therebetween.

[0012] Further, the thickness of the internal rib plate is 2 mm to 4 mm; the thicknesses of multiple internal rib plates are completely the same or the thicknesses of some internal rib plates are different, and the thickness of each internal rib plate remains unchanged along its length direction or changes according to specific support strength and stiffness requirements; the height of the internal rib plate changes adaptively with the height of the gas circulation channel.

[0013] Furthermore, the casing body includes connection discs at both ends thereof, an intake section having one end connected to the connection disc at the intake end and extending axially in a cylindrical shape to cooperate with the internal flow passage ring, a first flared section connected to the intake section and having a flared shape, a connection section connected radially to the flared end of the first flared section, and a second flared section connected to the connection section and flared axially. The flared end of the second flared section is connected to the connection disc at the outlet end; the connection section and the second flared section are used to cooperatively connect the diffuser housing and form a first chamber and a second chamber for bleeding air therebetween.

[0014] Furthermore, the integrated casing body further includes a plurality of external rib plates connected to the outer walls of the connection section, the first flared section, and the intake section. The plurality of external rib plates are sequentially arranged at intervals in the circumferential direction.

[0015] Furthermore, the thickness of the external rib plates is 2 mm to 4 mm; the thicknesses of the multiple external rib plates are the same or the thicknesses of some of the external rib plates are different. The length of each external rib plate in its length direction varies according to the strength and stiffness requirements of its installation position, and the thickness of each external rib plate in its length direction also varies according to the strength and stiffness requirements of its installation position.

[0016] According to another aspect of the present invention, there is also provided a centrifugal compressor, including a centrifugal compressor casing adapted to a super-high pressure ratio as described in any one of the above, and an integrally formed one-piece diffuser; the compressor casing is axially connected to the one-piece diffuser.

[0017] The present invention has the following beneficial effects:

[0018] The solution of the present invention relates to a compressor casing structure suitable for a super-high pressure ratio compressor. In this compressor casing structure, the intake casing, adapter casing, impeller shroud, diffuser casing, etc. of the traditional structure are integrated into an integrated casing body. If a one-piece diffuser is further equipped, there are only two stator parts in the compressor part. This structure maximally realizes the integration of the stator parts of the compressor, ensures extremely high economy of the stator parts, simplifies the structure to the greatest extent, has few parts, low processing, disassembly, and maintenance costs, significantly reduces the weight, and only needs to meet the lowest assembly process requirements of the centrifugal impeller during assembly. The assembly is simple and the assembly accuracy is high;

[0019] On the other hand, compared with the prior art, the structure of the present invention simplifies and designs at low cost to the greatest extent, cancels the adjustable guide vane structure and bleed chamber structure that can expand the stable operating range in the existing structure. In the present invention, improvement measures adapted to the super-high pressure ratio performance are taken, such as Figure 2 and Figure 6As shown in the figure, the adjustable guide vane structure is simplified to an integral guide vane with a targeted design integrated on the casing integrated body, that is, the inlet guide vane. It is integrated with the casing integrated body into one part and does not need to be installed separately. Therefore, by keeping the inlet guide vane fixed, the stability of the inlet air flow in the working state can be maximally improved. At the same time, a plurality of gas circulation channels arranged at circumferential intervals are provided on the inner wall surface of the inlet air flow passage. The gas generated during the intermediate state or transition state operation of the centrifugal impeller can first enter the gas circulation channels and then be discharged into the inlet air flow passage from the air outlet ends of the gas circulation channels, forming a self-circulation structure. On the one hand, gas loss is reduced. Compared with the existing structure, the stable working range can be improved without intermediate air bleeding. Therefore, the structure is simple and the working stability is high, which can effectively improve the stable working margin of the compressor and prevent surging. On the other hand, the gas circulation channels are integrally processed and the forming process is simple. By increasing a small amount of mass, the effect of improving the stable margin of the ultra-high pressure ratio compressor can be achieved. Compared with the traditional method of improving the stable margin by gas collection and air bleeding, this structure is simpler, can save the cost of multiple parts and accessories such as air bleeding valves, and the benefit-cost ratio is extremely high.

[0020] In addition to the purposes, features and advantages described above, the present invention has other purposes, features and advantages. The present invention will be further described in detail below with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0022] Figure 1 is the front view structural schematic diagram of the centrifugal compressor according to the preferred embodiment of the present invention;

[0023] Figure 2 is Figure 1 the front view structural schematic diagram of the centrifugal compressor casing adapted to the ultra-high pressure ratio in

[0024] Figure 3 is Figure 2 the schematic diagram of the gas circulation channel size design in

[0025] Figure 4 is Figure 3 the sectional view structural schematic diagram in the A-A direction in

[0026] Figure 5 is Figure 3 the sectional view structural schematic diagram in the B-B direction in

[0027] Figure 6 is the half-sectional view structural schematic diagram of the centrifugal compressor according to the preferred embodiment of the present invention.

[0028] LEGEND DESCRIPTION:

[0029] 1. Casing integrated body; 101. Inlet air flow passage; 102. Gas circulation passage; 103. Air collecting cavity; 104. First chamber; 105. Second chamber; 11. Casing body; 111. Inlet section; 112. First flared section; 113. Connection section; 114. Second flared section; 12. Internal flow passage ring; 13. Internal rib plate; 14. External rib plate;

[0030] 2. Inlet guide vane;

[0031] 3. Centrifugal impeller;

[0032] 4. Integral diffuser. Specific embodiments

[0033] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways defined and covered by the following.

[0034] Referring to Figure 2 and Figure 6 , a preferred embodiment of the present invention provides a centrifugal compressor casing adapted to a super high pressure ratio, including: a casing integrated body 1 integrating the existing inlet casing, adapter casing, impeller shroud and diffuser casing in an integrated design, and multiple inlet guide vanes 2 integrally designed with the casing integrated body 1. The multiple inlet guide vanes 2 are sequentially and spaced circumferentially along the inner wall surface of the inlet air flow passage 101 in the casing integrated body 1. A plurality of gas circulation passages 102 are also provided at intervals along the circumferential direction inside the inner wall surface of the inlet air flow passage 101 of the casing integrated body 1. The plurality of gas circulation passages 102 extend along the inlet axis, and both ends of each gas circulation passage 102 penetrate the inner wall surface of the casing integrated body 1 to communicate with the inlet air flow passage 101, thereby forming a gas self-circulation structure.

[0035] The solution of the present invention relates to a compressor casing structure applicable to a super high pressure ratio compressor. In this compressor casing structure, the inlet casing, adapter casing, impeller shroud and diffuser casing of the traditional structure are integrated into a casing integrated body 1. If an integral diffuser is further equipped, there are only two stator parts in the compressor part. This structure maximally realizes the integration of the stator parts of the compressor, ensures extremely high economy of the stator parts, simplifies the structure to the greatest extent, has few parts, low processing, disassembly and maintenance costs, significantly reduces the weight, and only needs to meet the lowest assembly process requirements of the centrifugal impeller during assembly. The assembly is simple and the assembly accuracy is high;

[0036] On the other hand, compared with the prior art, the structure of the present invention is simplified to the greatest extent and designed with low cost, and the adjustable guide vane structure and the bleed chamber structure that can expand the stable working range in the existing structure are cancelled. In the present invention, improvement measures adapted to the ultra-high pressure ratio performance are adopted, such as Figure 2 and Figure 6 shown. Among them, the adjustable guide vane structure is simplified to an integral guide vane with a targeted design integrated on the casing integrated body 1, that is, the inlet guide vane 2, which is integrated with the casing integrated body 1 into one part and does not need to be installed separately. Therefore, the inlet guide vane 2 can be kept fixed to maximize the stability of the inlet air flow in the working state. At the same time, a plurality of gas circulation channels 102 arranged at circumferential intervals are provided on the inner wall surface of the inlet air flow passage 101. The gas generated when the centrifugal impeller works in the intermediate state or the transition state can first enter the gas circulation channels 102, and then be discharged into the inlet air flow passage 101 from the air outlet end of the gas circulation channels 102 to form a self-circulation structure. On the one hand, the gas loss can be reduced. Compared with the existing structure, the stable working range can be improved without intermediate bleeding. Therefore, the structure is simple and the working stability is high, and the stable working margin of the compressor can be effectively improved to prevent surging. On the other hand, the gas circulation channels 102 are integrally processed, and the forming process is simple. Increasing a small amount of mass can achieve the effect of improving the stable margin of the ultra-high pressure ratio compressor. Compared with the traditional structure that improves the stable margin by gas collection and bleeding, this structure is simpler and can save the cost of multiple parts and accessories such as bleed valves. The benefit-cost ratio is extremely high.

[0037] Optionally, as Figure 2 shown, an annular air collection cavity 103 recessed inward is further provided on the inner wall surface of the inlet air flow passage 101. The air collection cavity 103 is close to the impeller tip of the centrifugal impeller 3 installed in the inlet air flow passage 101, and the air collection cavity 103 communicates with the inlet end of the gas circulation channels 102 to form an air inlet, and the air outlet end of the gas circulation channels 102 extends to be close to the inlet port of the inlet air flow passage 101. During operation, the gas generated when the centrifugal impeller works in the intermediate state or the transition state first enters the air collection cavity 103 for air collection, then enters the gas circulation channels 102, and finally enters the inlet air flow passage 101 from the inlet end of the inlet air flow passage 101 to form a self-circulation structure. The stable working range of the compressor can be improved without intermediate bleeding, and there is no need to set a bleed chamber and a bleed valve, which also makes the overall structure simple.

[0038] Preferably, as Figure 3 shown, the axial width of the air collection cavity 103 is 1 mm to 2 mm. The radial width of the air outlet of the air outlet end of the gas circulation channels 102 is 2 mm to 3 mm. In this preferred solution, by adjusting the parameters of the air collection cavity 103 and the gas circulation channels 102, such as the air inlet width s1 and the air outlet width s2, the effect of improving the stable working range of the self-circulation can be controlled.

[0039] In this alternative solution, as Figure 2 and Figure 6 shown, the casing integrated body 1 includes a hollow cylindrical casing body 11, an internal flow passage ring 12, and a plurality of internal rib plates 13 for connection. The internal flow passage ring 12 is located inside the casing body 11. The plurality of internal rib plates 13 are arranged at intervals in the circumferential direction and are connected between the inner wall surface of the casing body 11 and the outer wall surface of the internal flow passage ring 12, so that a plurality of gas circulation channels 102 are formed at intervals in the circumferential direction between the inner wall surface of the casing body 11 and the outer wall surface of the internal flow passage ring 12. The inner channel of the internal flow passage ring 12 forms an inlet air flow passage 101. A plurality of inlet guide vanes 2 are connected to the inner wall surface of the internal flow passage ring 12 at intervals in the circumferential direction. The air flow passage formed by the casing body and the internal flow passage ring is a structure for stabilizing the super-high pressure ratio centrifugal compressor.

[0040] In the present invention, a plurality of parts are highly integrated into a casing integrated body 1. In addition to ensuring the working stability, at ultra-high temperature gradients, the design of the strength, deformation coordination, etc. of the parts themselves is a design difficulty. Coupled with the need to be integrated into a casing integrated body 1, the design difficulty is greatly increased. In the structure of the present invention, the internal flow passage ring 12 is connected to the inner wall surface of the casing body 11 through the internal rib plates 13 and forms part of the flow passage, that is, the gas circulation channel 102. On the one hand, it can reduce the internal stress in the high temperature gradient area, and at the same time form a partial isolation only connected by the internal rib plates 13 with the high temperature area of the casing body 11 (due to gas compression, the temperature is higher closer to the diffuser part), which is beneficial to controlling the thermal deformation of the inlet air flow passage 101, and thus better controlling the radial working clearance between the centrifugal impeller and the outer casing inlet (because the thermal clearance at this position is highly sensitive to the performance of the compressor); on the other hand, the gas collecting cavity 103 and the gas circulation channel 102 divide the casing body 11 into multiple parts. Among them, the casing body 11 can also adjust the wall thickness of its local position to ensure the overall strength and adjust the stiffness of the casing integrated body 1. At the same time, the internal rib plates 13 can also achieve the purpose of ensuring the strength and adjusting the stiffness of the casing integrated body 1 by adjusting the specific structural parameters. Therefore, in the structure of the present invention, the stiffness adjustment and the independent internal flow passage ring 12 structure are specifically adopted to ensure its strength and thermal deformation coordination under high temperature gradients, and the internal stability structure is adopted to ensure the stability of its working performance. In addition, by adjusting the wall thickness and the rib plate thickness, a parametric structure with strength meeting the design requirements, flow passage deformation matching the best aerodynamic performance, and relatively light overall mass can be obtained.

[0041] In this alternative solution, as Figure 2As shown, an air collecting cavity 103 is formed by the concave inner wall surface of the casing body 11. The first ends of the internal flow passage ring 12 and the internal rib plate 13 close to the air collecting cavity 103 are flush, and the first ends of both form the outer wall of the air collecting cavity 103. The second end of the internal rib plate 13 extends to be close to the air inlet port of the casing body 11, and the second end of the internal flow passage ring 12 extends axially close to the second end of the internal rib plate 13 to form an air outlet of the gas circulation passage 102 between the two.

[0042] In this alternative solution, as Figure 3-4 shown, the thickness of the internal rib plate 13 is 2 mm to 4 mm. At this size, the required heat deformation effect of the flow passage surface and a lighter mass can be obtained. The thicknesses of multiple internal rib plates 13 are completely the same or the thicknesses of some internal rib plates 13 are different, and the thickness of each internal rib plate 13 remains unchanged along its length direction or changes according to specific support strength and stiffness requirements. The height of the internal rib plate 13 changes adaptively with the height of the gas circulation passage 102. During design, the air collecting cavity 103 and the gas circulation passage 102 divide the casing body 11 into multiple parts. Among them, the casing body 11 can ensure the strength of the integrated casing body 1 and adjust the stiffness by adjusting the wall thickness at local positions. The internal rib plate 13 can also achieve the purpose of ensuring the strength of the integrated casing body 1 and adjusting the stiffness by adjusting specific structural parameters (as Figure 3-4 shown, adjusting the height and thickness h1, t1 of the internal rib plate 13, the wall thickness t at different positions of the casing body 11, and the number of internal rib plates 13, etc. The thicker the wall thickness at different positions of the casing body 11, the stronger the stiffness, and the thicker the internal rib plate 13, the stronger the stiffness; at the same time, the internal rib plate 13 can also strengthen the strength of weak positions. When setting, according to the working conditions, the position parameters are adjusted and determined during the design process. After the design is completed, the strength and stiffness are immediately determined, and the range of this structural parameter is obtained through multi-disciplinary iterative optimization, which can achieve a more coordinated heat deformation effect of the flow passage surface and a better effect of improving the stable working margin of the compressor.

[0043] Optionally, as Figure 2-3 shown, the casing body 11 includes connection discs at both ends thereof, an air inlet section 111 having one end connected to the connection disc at the air inlet end and extending axially in a cylindrical shape to cooperate with the internal flow passage ring 12, a first flared section 112 connected to the air inlet section 111 and having a flared shape, a connection section 113 connected to the flared end of the first flared section 112 in the radial direction, and a second flared section 114 connected to the connection section 113 and having a flared shape axially. The flared end of the second flared section 114 is connected to the connection disc at the air outlet end. The connection section 113 and the second flared section 114 are used to cooperate with and connect the diffuser housing, and a first chamber 104 and a second chamber 105 for air extraction are formed therebetween. Compared with the traditional structure, this position structure setting can ensure the original air extraction function is basically retained while reducing the total mass.

[0044] Furthermore, asFigure 2 As shown in the figure, the casing integrated body 1 further includes a plurality of external rib plates 14 connected to the outer wall surfaces of the connecting section 113, the first flared section 112, and the intake section 111. The plurality of external rib plates 14 are arranged at intervals in the circumferential direction in sequence. In actual design, in addition to the casing body 11 being able to ensure the strength and adjust the stiffness of the casing integrated body 1 by adjusting the wall thickness at local positions, the external rib plates 14 can also achieve the purpose of ensuring the strength and adjusting the stiffness of the casing integrated body 1 by adjusting specific structural parameters. For example Figure 5 As shown in the figure, the height and thickness h2, t2 of the adjustable external rib plates 14 and the number of the external rib plates 14 can be adjusted. The thicker and higher the external rib plates 14 are, the stronger the stiffness is. At the same time, the external rib plates 14 can also strengthen the strength of the weak positions. According to the working conditions, the position parameters are adjusted and determined during the design process. After the design is completed, the strength and stiffness are determined immediately.

[0045] In this alternative solution, for example Figure 3 and Figure 5 As shown in the figure, the thickness of the external rib plates 14 is 2 mm to 4 mm. At this size, the required thermal deformation effect of the flow channel surface and a lighter mass can be obtained. The thicknesses of multiple external rib plates 14 are the same or the thicknesses of some external rib plates 14 are different. The lengths of each external rib plate 14 along its length direction are different according to the strength and stiffness requirements of its installation position, and the thicknesses of each external rib plate 14 along its length direction are also different according to the strength and stiffness requirements of its installation position.

[0046] During design, under ultra-high temperature gradients, the strength and deformation coordination design of parts becomes a design difficulty. Coupled with the need to be integrated into one part, the design difficulty is greatly increased. The present invention innovatively adopts a structure with enhanced strength and deformation coordination and an integrated double-layer structure (the casing body 11 and the internal flow channel ring 12) for the casing integration under ultra-high temperature gradients at ultra-high pressure ratios to overcome the problems brought by high temperature gradients, and at the same time, the one-piece processing cost is basically not increased; at the same time, the gas circulation channel 102 formed by the internal rib plates 13, the casing body 11, and the internal flow channel ring 12 can be designed and optimized to form a self-circulating stability-enhancing structure with an ultra-high pressure ratio, so as to solve the problem of insufficient surge margin of the ultra-high pressure ratio compressor.

[0047] Refer to Figure 1, a preferred embodiment of the present invention further provides a centrifugal compressor, which includes a centrifugal compressor casing adapted to a super-high pressure ratio as described in any one of the above, and an integrally formed diffuser 4. The compressor casing is axially connected to the integrally formed diffuser 4. In the centrifugal compressor of the present invention, the integration of the compressor stator parts is maximally achieved, ensuring extremely high economy of the stator parts. At the same time, the structure is maximally simplified, with a small number of parts, low processing, assembly, disassembly and maintenance costs, and a significant reduction in weight. During assembly, only the lowest assembly process requirements of the centrifugal impeller need to be ensured, and the assembly is simple and the assembly accuracy is high. On the other hand, the inlet guide vane 2 is integrated with the casing body 1 into one part and does not need to be installed separately. Thus, by keeping the inlet guide vane 2 fixed, the stability of the inlet air flow in the working state can be maximally improved, and a self-circulation structure can be formed to reduce gas loss. Compared with the existing structure, it can increase the stable working range without intermediate bleeding, so the structure is simple and the working stability is high, which can effectively improve the stable working margin of the compressor and prevent surging.

[0048] The foregoing is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A centrifugal compressor casing adapted to a super high pressure ratio, characterized in that Comprising: A casing integrated body (1) integrating the existing intake casing, adapter casing, impeller shroud and diffuser casing, and multiple inlet guide vanes (2) integrally designed with the casing integrated body (1). The multiple inlet guide vanes (2) are sequentially and spacedly connected along the circumferential direction of the casing integrated body (1) to the inner wall surface of the intake air flow passage (101) inside the casing integrated body (1); Inside the inner wall surface of the intake air flow passage (101) of the casing integrated body (1), multiple gas circulation channels (102) are sequentially and spacedly arranged along the circumferential direction. The multiple gas circulation channels (102) extend along the intake air axis, and both ends of each gas circulation channel (102) penetrate the inner wall surface of the casing integrated body (1) respectively to communicate with the intake air flow passage (101), thereby forming a gas self-circulation structure; On the inner wall surface of the intake air flow passage (101), there is also a gas collecting cavity (103) recessed in a ring shape. The gas collecting cavity (103) is close to the impeller tip of the centrifugal impeller (3) to be installed in the intake air flow passage (101), and the gas collecting cavity (103) communicates with the intake end of the gas circulation channel (102) to form an intake port. The outlet end of the gas circulation channel (102) extends to be close to the intake port of the intake air flow passage (101); The casing integrated body (1) includes a hollow cylindrical casing body (11) and an internal flow channel ring (12), and multiple internal rib plates (13) for connection; the internal flow channel ring (12) is located inside the casing body (11). The multiple internal rib plates (13) are sequentially and spacedly arranged along the circumferential direction and are connected between the inner wall surface of the casing body (11) and the outer wall surface of the internal flow channel ring (12), so that multiple gas circulation channels (102) are formed between the inner wall surface of the casing body (11) and the outer wall surface of the internal flow channel ring (12) and are sequentially and spacedly arranged along the circumferential direction; the inner channel of the internal flow channel ring (12) forms the intake air flow passage (101), and multiple inlet guide vanes (2) are sequentially and spacedly connected to the inner wall surface of the internal flow channel ring (12) along the circumferential direction; The inner wall surface of the casing body (11) is recessed to form the gas collecting cavity (103); the first ends of the internal flow channel ring (12) and the internal rib plates (13) close to the gas collecting cavity (103) are flush, and the first ends of the two form the outer wall of the gas collecting cavity (103); the second ends of the internal rib plates (13) extend to be close to the intake port of the casing body (11), and the second end of the internal flow channel ring (12) extends axially to be close to the second end of the internal rib plate (13), so as to form an outlet of the gas circulation channel (102) between the two.

2. The centrifugal compressor casing adapted to a super high pressure ratio according to claim 1, wherein The width of the gas collecting cavity (103) along the axial direction is 1 mm to 2 mm; The width of the outlet of the outlet end of the gas circulation channel (102) along the radial direction is 2 mm to 3 mm.

3. The centrifugal compressor casing adapted to a super high pressure ratio according to claim 1, wherein The thickness of the internal rib plate (13) is 2 mm to 4 mm; The thicknesses of multiple internal rib plates (13) are completely the same, or the thicknesses of some internal rib plates (13) are different. The thickness of each internal rib plate (13) remains unchanged along its length direction or varies according to specific support strength and stiffness requirements. The height of the internal rib plate (13) changes adaptively with the height of the gas circulation channel (102).

4. The centrifugal compressor casing adapted to a super high pressure ratio according to claim 1, wherein the casing body (11) includes connection discs at both ends thereof, an intake section (111) having one end connected to the connection disc at the intake end and extending axially in a cylindrical shape to cooperate with the internal flow path ring (12), a first flared section (112) connected to the intake section (111) and having a flared shape, a connection section (113) connected radially to the flared end of the first flared section (112), and a second flared section (114) connected to the connection section (113) and having a flared shape axially. The flared end of the second flared section (114) is connected to the connection disc at the outlet end. The connection section (113) and the second flared section (114) are used to cooperatively connect to the diffuser housing and form a first chamber (104) and a second chamber (105) for air extraction therebetween.

5. The centrifugal compressor casing adapted to a super high pressure ratio according to claim 4, wherein the casing integrated body (1) further includes a plurality of external rib plates (14) connected to the outer wall surfaces of the connection section (113), the first flared section (112), and the intake section (111). The plurality of external rib plates (14) are sequentially arranged at intervals circumferentially.

6. The centrifugal compressor casing adapted to a super high pressure ratio according to claim 5, wherein the thickness of the external rib plate (14) is 2 mm to 4 mm; the thicknesses of multiple external rib plates (14) are the same or the thicknesses of some external rib plates (14) are different. The length of each external rib plate (14) along its length direction is different according to the strength and stiffness requirements of its installation position, and the thickness of each external rib plate (14) along its length direction is also different according to the strength and stiffness requirements of its installation position.

7. A centrifugal compressor, characterized in that, It includes the centrifugal compressor casing adapted to a super high pressure ratio according to any one of claims 1 - 6, and an integrally formed integrated diffuser (4); The compressor casing is axially connected to the integrated diffuser (4).

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