Centrifugal compressor and refrigerating system

Abstract

The utility model relates to a centrifugal compressor and a refrigerating system.The centrifugal compressor comprises a first static part, a second static part and an impeller, the impeller comprises a hub, and a first leakage cavity is formed between the back side end face of the hub and the first static part; a second leakage cavity is formed between the outer side of the wheel cover and the second static part; the blades are distributed in the circumferential direction of the hub at intervals and connected between the hub and the wheel cover; the first pressurizing assembly is connected to the back side end face of the hub and is configured to increase the air pressure in the first leakage cavity in the rotating process of the impeller so as to additionally apply first thrust to the back side end face of the hub, and the second pressurizing assembly is connected to the outer side of the impeller cover and is configured to increase the air pressure in the first leakage cavity so as to additionally apply second thrust to the back side end face of the hub. The air pressure increasing device is configured to increase the air pressure in the second leakage cavity in the impeller rotating process so as to additionally apply second thrust to the outer side of the impeller cover, and the vector sum of the first thrust and the second thrust is opposite to the axial force direction of the centrifugal compressor.

Description

Technical Field

[0001] The present disclosure relates to the technical field of refrigeration systems, and in particular to a centrifugal compressor and a refrigeration system. Background Art

[0002] Centrifugal refrigeration compressors are high-speed compressors. The compressor rotor rotates at high speed during operation and will bear different loads from the axial direction. At present, the main environmentally friendly oil-free bearings are electromagnetic bearings and gas bearings. Since the bearing capacity of magnetic suspension and gas suspension compressors is weak, the axial load of centrifugal compressors varies greatly when operating under variable working conditions, resulting in an unbalanced axial force of the centrifugal compressor, which is easy to exceed the bearing capacity and cause serious wear on the working surface of the bearing. Utility Model Content

[0003] Embodiments of the present disclosure provide a centrifugal compressor and a refrigeration system, which can reduce the axial force of the centrifugal compressor.

[0004] According to a first aspect of the present disclosure, a centrifugal compressor is provided, comprising a first stationary member, a second stationary member and an impeller, wherein the impeller is rotatable about a central axis and comprises:

[0005] A wheel hub, wherein a first leakage cavity is formed between a back side end surface of the wheel hub and the first stationary member;

[0006] A wheel cover is coaxially arranged with the wheel hub and sleeved on the outer side of the wheel hub, and a second leakage chamber is formed between the outer side of the wheel cover and the second stationary member;

[0007] A plurality of blades are spaced apart along the circumference of the hub and connected between the hub and the wheel cover; and

[0008] A first boost component and / or a second boost component, the first boost component is connected to the back end face of the hub, and is configured to increase the air pressure in the first leakage chamber during the rotation of the impeller to additionally apply a first thrust to the back end face of the hub, and the second boost component is connected to the outer side of the wheel cover, and is configured to increase the air pressure in the second leakage chamber during the rotation of the impeller to additionally apply a second thrust to the outer side of the wheel cover, and the overall thrust formed by the first thrust and / or the second thrust is opposite to the axial force direction of the centrifugal compressor.

[0009] In some embodiments,

[0010] The first supercharging assembly includes a first baffle plate and a plurality of first rib plates, the first baffle plate extends in a circumferential direction and is arranged radially outside the plurality of first rib plates, the plurality of first rib plates are arranged at intervals in the circumferential direction, and the plurality of first rib plates extend from an area close to the central axis to an area close to the first baffle plate; and / or

[0011] The second boost assembly includes a second baffle and a plurality of second ribs. The second baffle extends circumferentially and is arranged in an area close to the air outlet relative to the plurality of second ribs. The plurality of second ribs are arranged at intervals along the circumferential direction. The plurality of second ribs extend from an area close to the air inlet to an area close to the first baffle.

[0012] In some embodiments,

[0013] The height of the first baffle is higher than the height of the first rib; and / or

[0014] The height of the second baffle plate is higher than that of the second rib plate.

[0015] In some embodiments, the first baffle plate and / or the second baffle plate are in a ring shape.

[0016] In some embodiments, the first rib extends in a radial direction, and / or the second rib is located in a radial plane.

[0017] In some embodiments,

[0018] The axial protrusion height of the first rib is 0.4 to 0.6 times the axial dimension of the first leakage cavity; and / or

[0019] The axial protruding height of the second rib is 0.4 to 0.6 times the axial dimension of the second leakage cavity.

[0020] In some embodiments,

[0021] A first sealing portion is provided on the radial inner side of the first baffle plate, and the first sealing portion is radially located between the first stationary member and the first baffle plate, and / or a second sealing portion is provided on the radial outer side of the first baffle plate, and the second sealing portion is radially located between the first stationary member and the first baffle plate; and / or

[0022] A third sealing portion is provided on the radial inner side of the second baffle plate and is radially located between the second stationary member and the second baffle plate, and / or a fourth sealing portion is provided on the radial outer side of the second baffle plate and is radially located between the second stationary member and the second baffle plate.

[0023] In some embodiments, a fifth sealing portion is provided at the outlet of the first leakage cavity, and / or a sixth sealing portion is provided at the outlet of the second leakage cavity.

[0024] In some embodiments, in the case where the centrifugal compressor is a two-stage compressor with an impeller placed at one end, if the impeller is a first-stage impeller, the first stationary part is a return flow device, and the second stationary part is a first-stage diffuser; if the impeller is a second-stage impeller, the first stationary part is a compressor housing, and the second stationary part is a second-stage diffuser.

[0025] In some embodiments, when the centrifugal compressor is a two-stage compressor with an impeller placed at both ends, if the impeller is a first-stage impeller, the first stationary part is a first-stage diffuser, and the second stationary part is a first-stage volute; if the impeller is a second-stage impeller, the first stationary part is a second-stage diffuser, and the second stationary part is a second-stage volute.

[0026] According to a second aspect of the present disclosure, a refrigeration system is provided, comprising the centrifugal compressor of the above embodiment.

[0027] Based on the above technical scheme, the centrifugal compressor of the embodiment of the present invention has a simple structure. The first boost component can apply a first thrust to the dorsal end face of the wheel hub, and the second boost component can apply a second thrust to the outer side of the wheel cover. The first boost component and the second boost component can be selectively set, and the overall thrust formed by the first thrust and / or the second thrust is opposite to the axial force direction of the centrifugal compressor, which can reduce the axial force of the centrifugal compressor, reduce the bearing capacity required for the axial bearing of the centrifugal compressor, reduce the wear of the working surface of the axial bearing, improve the working life of the axial bearing, and improve the reliability of the axial bearing and the reliability of the centrifugal compressor; by increasing the air pressure in the first leakage chamber and the second leakage chamber, the pressure difference between the air outlet and the leakage chamber can be reduced, the leakage resistance of the gas can be increased, the leakage amount of the gas through the first leakage chamber and the second leakage chamber can be reduced, the operating performance of the compressor can be improved, and energy can be saved; it can avoid increasing the leakage gap at the seal due to balancing the axial force by increasing the balancing plate, etc., so as to achieve both balancing the axial force and reducing the gas leakage loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings described herein are used to provide a further understanding of the present disclosure and constitute a part of the present application. The illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation on the present disclosure. In the drawings:

[0029] Figure 1 It is a schematic structural diagram of some embodiments of the impeller of the centrifugal compressor disclosed in the present invention from a first perspective.

[0030] Figure 2 It is a structural schematic diagram of some embodiments of the impeller of the centrifugal compressor disclosed in the present invention from a second perspective.

[0031] Figure 3 It is a schematic structural diagram of some embodiments of the cooperation between the hub and the second stationary member of the centrifugal compressor disclosed in the present invention.

[0032] Figure 4 Schematic diagram of the structure of some embodiments of a two-stage compressor with an impeller placed at one end of the present invention.

[0033] Figure 5 Schematic diagram of the structure of some embodiments of the two-stage compressor with impellers placed at both ends of the present disclosure.

[0034] Description of Reference Numerals

[0035] 1. Hub; 2. Wheel cover; 3. Blade; 4. First supercharger assembly; 41. First baffle; 42. First rib; 5. Second supercharger assembly; 51. Second baffle; 511. Third sealing portion; 512. Fourth sealing portion; 52. Second rib; 61. First diffuser; 62. Second diffuser; 7. Return; 8. Thrust bearing; 9. Thrust plate; a. Central axis; 10. First leakage chamber; 11. Air inlet; 12. Fifth sealing part; 20. Second leakage chamber; 21. Air outlet; 22. Sixth sealing part; 100. First-stage impeller; 200. Second-stage impeller; 210. First-stage volute; 220. Second-stage volute; 101. First stationary part; 102. Second stationary part; 121. Interstage seal; 122. Second-stage rear seal; 221. First-stage front seal; 222. Second-stage front seal; 300. Motor cylinder; 400. Motor stator. DETAILED DESCRIPTION

[0036] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is in no way intended to limit the present disclosure and its application or use. The present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present disclosure thorough and complete and to fully express the scope of the present disclosure to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the components and steps, the composition of the materials, the numerical expressions and the numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary and not as limiting.

[0037] The words "first", "second" and similar words used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different parts. The words "include" or "comprise" and similar words mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of including other elements. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0038] In the present disclosure, when a specific device is described as being located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device. When a specific device is described as being connected to other devices, the specific device may be directly connected to the other device without an intermediate device, or may not be directly connected to the other device but have an intermediate device.

[0039] All terms (including technical terms or scientific terms) used in the present disclosure have the same meanings as those understood by ordinary technicians in the field to which the present disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries, such as general dictionaries, should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless explicitly defined herein.

[0040] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0041] Based on the above-mentioned embodiments of the present disclosure, in the absence of explicit negation or conflict, the technical features of one embodiment may be beneficially combined with one or more other embodiments.

[0042] During the research process, the inventor discovered that the hydrodynamic air bearing currently used in engineering mainly uses gas as a lubricating medium. Its rotor has a relatively low load-bearing capacity under low-speed operation, and its damping and stiffness are also relatively low. Due to the low rotor speed of the dynamic pressure gas at startup, the air pressure in the bearing is insufficient and the supporting force is insufficient, which will cause the axial bearing to be in a dry friction state. Only when the axial bearing speed reaches a certain value can a hydrodynamic air film be formed and enter a stable gas lubrication state. The gas bearing has a low load-bearing capacity. When the centrifugal compressor is running under variable operating conditions, the axial load changes greatly, which is easy to exceed the bearing load-bearing capacity, causing serious wear on the working surface of the bearing, reducing the working life, and reducing reliability. Due to the magnetic saturation and electromagnetic heating of the material, it is also impossible to further improve the load-bearing capacity of the electromagnetic bearing.

[0043] At the same time, the inventors also found during the research process that magnetic suspension and air suspension compressors are suitable for small-capacity compressors due to their weak bearing capacity, and the energy efficiency of small-capacity compressors is mainly affected by leakage loss. When designing a compressor, it is necessary to increase the balance disk to reduce the balancing axial force, but increasing the balance disk will increase the leakage gap at the compressor seal, resulting in reduced energy efficiency and energy waste.

[0044] To solve at least one of the above problems, firstly, the present disclosure provides a centrifugal compressor, such as Figures 1 to 5 As shown, it includes a first stationary member 101, a second stationary member 102 and an impeller, the impeller is rotatable around a central axis a and includes:

[0045] The wheel hub 1 forms a first leakage chamber 10 between the back side end surface of the wheel hub 1 and the first stationary member 101;

[0046] The wheel cover 2 is coaxially arranged with the wheel hub 1 and sleeved on the outer side of the wheel hub 1, and a second leakage chamber 20 is formed between the outer side of the wheel cover 2 and the second stationary member 102;

[0047] A plurality of blades 3 are spaced apart along the circumference of the hub 1 and connected between the hub 1 and the wheel cover 2; and

[0048] The first boost component 4 and / or the second boost component 5, the first boost component 4 is connected to the back end face of the hub 1, and is configured to increase the air pressure in the first leakage chamber 10 during the rotation of the impeller to additionally apply a first thrust to the back end face of the hub 1, the second boost component 5 is connected to the outer side of the wheel cover 2, and is configured to increase the air pressure in the second leakage chamber 20 during the rotation of the impeller to additionally apply a second thrust to the outer side of the wheel cover 2, and the overall thrust formed by the first thrust and / or the second thrust is opposite to the axial force direction of the centrifugal compressor.

[0049] Specifically, by arranging the first boosting assembly 4 on the back side end face of the hub 1, the gas pressure in the first leakage chamber 10 is increased, and the thrust on the back side end face of the hub 1 can be increased, that is, the increased gas pressure generates an additional first thrust on the back side end face of the hub 1; by arranging the second boosting assembly 5 on the outside of the wheel cover 2, the gas pressure in the second leakage chamber 20 is increased, and the thrust on the outside of the wheel cover 2 can be increased, that is, the increased gas pressure generates an additional second thrust on the outside of the wheel cover 2. By adding the above thrust in the centrifugal compressor, the overall thrust formed by the first thrust and the second thrust is opposite to the axial force of the centrifugal compressor, which can reduce the axial force of the centrifugal compressor, or make the axial force completely balanced, even if the axial force is zero.

[0050] Specifically, the first thrust and the second thrust are in opposite directions, the first thrust is directed from the back side of the hub 1 to the outside of the wheel cover 2 along the axial direction, and the second thrust is directed from the outside of the wheel cover 2 to the back side of the hub 1 along the axial direction. The overall thrust includes three situations: when the centrifugal compressor is only provided with the first supercharging assembly 4, the overall thrust includes only the first thrust; when the centrifugal compressor is only provided with the second supercharging assembly 5, the overall thrust includes only the second thrust; when the centrifugal compressor is provided with both the first supercharging assembly 4 and the second supercharging assembly 5, the overall thrust is the vector sum of the first thrust and the second thrust.

[0051] Specifically, in the prior art, the bearing capacity of the centrifugal compressor is insufficient when operating under different working conditions, resulting in an unbalanced axial force of the centrifugal compressor. The overall thrust formed by the first thrust and the second thrust is opposite to the direction of the initial axial force, which can improve the problem of insufficient axial bearing capacity of the compressor when operating under different working conditions. The axial force or initial axial force disclosed in the present invention refers to the excess axial force in addition to the thrust (axial) bearings such as the balancing plate or thrust plate adopted by the prior art centrifugal compressor, the gas bearings or electromagnetic bearings operating under normal working conditions, or other conventional axial force-bearing operations. The excess axial force exceeds the axial bearing capacity and causes axial bearing wear. The axial bearing is also called a thrust bearing. The axial bearing of the present application may include an oil-free bearing such as an electromagnetic bearing or a gas bearing.

[0052] Optionally, the compressor may be a single-stage compressor or a multi-stage compressor, such as a two-stage compressor, etc. The two-stage compressor includes a two-stage compressor with an impeller placed at one end and a two-stage compressor with an impeller placed at both ends, or a two-stage compressor with impellers arranged sequentially and a two-stage compressor with impellers arranged oppositely, or a single-cantilever two-stage compressor or a double-head-mounted two-stage compressor.

[0053] Optionally, when the compressor is a single-stage compressor, the direction of the axial force of the compressor is generally from the high-pressure side to the low-pressure side, or axially from the back side of the hub 1 to the outside of the wheel cover 2. The second thrust on the outside of the wheel cover 2 can be increased by only setting the second boost component 5 to reduce the axial force of the centrifugal compressor; the first boost component 4 and the second boost component 5 can also be set at the same time, and the second thrust is greater than the first thrust, to reduce the axial force of the centrifugal compressor.

[0054] Optionally, in the case where the compressor is a two-stage compressor with one end of the impeller placed, the direction of the axial force of the compressor is from the high-pressure side to the low-pressure side, or in other words, axially from the back side of the hub 1 to the outside of the wheel cover 2. The second thrust on the outside of the wheel cover 2 can be increased by only setting the second boost component 5 to reduce the axial force of the centrifugal compressor. The second boost component 5 can be set on the first-stage impeller 100 and / or the second-stage impeller 200; the first boost component 4 and the second boost component 5 can be set at the same time, and the sum of the second thrust of the first-stage impeller 100 and the second thrust of the second-stage impeller 200 is greater than the sum of the first thrust of the first-stage impeller 100 and the second thrust of the second-stage impeller 200 to reduce the axial force of the centrifugal compressor; similarly, in the case where the overall thrust direction formed by the first thrust and the second thrust is from the outside of the wheel cover 2 to the back side of the hub 1, the first boost component 4 can also be set on the first-stage impeller 100 or the second-stage impeller 200.

[0055] Optionally, in the case where the compressor is a two-stage compressor with impellers placed at both ends, if the direction of the axial force is from the first-stage impeller 100 to the second-stage impeller 200, the first boosting assembly 4 may be set only on the first-stage impeller 100, the second boosting assembly 5 may be set only on the second-stage impeller 200, or the first boosting assembly 4 may be set on the first-stage impeller 100 and the second boosting assembly 5 may be set on the second-stage impeller 200 at the same time; when the direction of the overall thrust is from the second-stage impeller 200 to the first-stage impeller 100, the second boosting assembly 5 may be set on the first-stage impeller 100, or the first boosting assembly 4 may be set on the second-stage impeller 200, or both the second boosting assembly 5 may be set on the first-stage impeller 100 and the first boosting assembly 4 may be set on the second-stage impeller 200.

[0056] Optionally, in the case where the compressor is a two-stage compressor with impellers placed at both ends, if the direction of the axial force is from the secondary impeller 200 to the primary impeller 100, the first boosting assembly 4 may be set only on the secondary impeller 200, the second boosting assembly 5 may be set only on the primary impeller 100, or the first boosting assembly 4 may be set on the secondary impeller 200 and the second boosting assembly 5 may be set on the primary impeller 100 at the same time; when the direction of the overall thrust is from the primary impeller 100 to the secondary impeller 200, the second boosting assembly 5 may also be set on the secondary impeller 200, or the first boosting assembly 4 may be set on the primary impeller 100, or both the second boosting assembly 5 may be set on the secondary impeller 200 and the first boosting assembly 4 may be set on the primary impeller 100.

[0057] Specifically, the hub 1 of the impeller is fixed on the motor rotor. When the centrifugal compressor is driven by the motor to run, the impeller is driven to rotate together. The impeller performs work on the gas through the blades 3 inside the impeller. The gas flows from the air inlet 11 to the air outlet 21. The air pressure at the air outlet 21 is higher than the air pressure at the air inlet 11, causing part of the gas to leak out from the air outlet 21 through the first leakage chamber 10 and the second leakage chamber 20.

[0058] Specifically, the gas pressure in the first leakage chamber 10 is increased by the first booster assembly 4, which can reduce the pressure difference between the air outlet 21 and the first leakage chamber 10, increase the gas leakage resistance, and reduce the gas leakage through the first leakage chamber 10. Correspondingly, the gas pressure in the second leakage chamber 20 is increased by the second booster assembly 5, which can reduce the pressure difference between the air outlet 21 and the second leakage chamber 20, increase the gas leakage resistance, and reduce the gas leakage through the second leakage chamber 20.

[0059] Optionally, the first leakage chamber 10 may also be referred to as an impeller rear chamber, and the second leakage chamber 20 may also be referred to as an impeller front chamber. Optionally, according to the specific structure of the compressor or the different installation positions of the impeller, the first stationary part 101 may include a returner 7, a compressor housing, a primary diffuser 61 or a secondary diffuser 62, etc., and the second stationary part 102 may include a primary diffuser 61, a secondary diffuser 62, a primary volute 210 or a secondary volute 220, etc.

[0060] The centrifugal compressor of this embodiment has a simple structure. The first boost component 4 can apply a first thrust to the dorsal end face of the hub 1, and the second boost component 5 can apply a second thrust to the outer side of the wheel cover 2. The first boost component 4 and the second boost component 5 can be selectively set. The overall thrust formed by the first thrust and / or the second thrust is opposite to the axial force direction of the centrifugal compressor, which can reduce the axial force of the centrifugal compressor, reduce the bearing capacity required for the axial bearing of the centrifugal compressor, reduce the wear of the working surface of the axial bearing, improve the working life of the axial bearing, and improve the reliability of the axial bearing and the reliability of the centrifugal compressor; by increasing the air pressure in the first leakage chamber 10 and the second leakage chamber 20, the pressure difference between the air outlet 21 and the leakage chamber can be reduced, the leakage resistance of the gas can be increased, the leakage amount of the gas through the first leakage chamber 10 and the second leakage chamber 20 can be reduced, the operating performance of the compressor can be improved, and energy can be saved; it can avoid increasing the leakage gap at the seal due to balancing the axial force by increasing the balancing plate, etc., so as to achieve both balancing the axial force and reducing the gas leakage loss.

[0061] In some embodiments, Figures 1 to 3 As shown,

[0062] The first supercharging assembly 4 includes a first baffle plate 41 and a plurality of first rib plates 42, the first baffle plate 41 extending in the circumferential direction and arranged on the radially outer side of the plurality of first rib plates 42, the plurality of first rib plates 42 being arranged at intervals in the circumferential direction, and the plurality of first rib plates 42 extending from an area close to the central axis a to an area close to the first baffle plate 41; and

[0063] The second supercharging assembly 5 includes a second baffle plate 51 and a plurality of second ribs 52. The second baffle plate 51 extends circumferentially and is arranged in an area close to the air outlet 21 relative to the plurality of second ribs 52. The plurality of second ribs 52 are arranged at intervals along the circumferential direction. The plurality of second ribs 52 extend from an area close to the air inlet 11 to an area close to the first baffle plate 41.

[0064] Specifically, since a plurality of first ribs 42 are arranged on the back end face of the impeller hub 1, the gas disturbance in the first leakage chamber 10 will be increased, and the gas in the cavity will be driven to flow toward the air outlet 21 with increased pressure under the action of centrifugal force, and the gas will be decelerated and pressurized after hitting the first baffle plate 41. Finally, the air pressure in the first leakage chamber 10 is increased, and the pressure difference between the air outlet 21 and the first leakage chamber 10 is reduced, thereby reducing the gas leakage amount of the first leakage chamber 10.

[0065] Specifically, the disturbance of the gas in the cavity by the first rib 42 can increase the pressure gradient of the gas in the cavity, so that the thrust on the back side end face of the hub 1 is increased, that is, the first thrust is additionally applied to the back side of the hub 1, and the magnitude of the first thrust is adaptively changed according to the operating condition of the compressor, and is adjusted by the impeller speed. For example, when the axial force of the compressor is directed from the outside of the wheel cover 2 to the back side of the hub 1, when the impeller speed increases, the air pressure of the air outlet 21 increases, and the axial force of the compressor increases. At this time, the air pressure in the first leakage cavity 10 also increases, and the first thrust increases, which helps to reduce the axial force of the centrifugal compressor.

[0066] Specifically, since a plurality of second ribs 52 are arranged on the outer side of the impeller cover 2, the gas disturbance in the second leakage chamber 20 will be increased, and the gas in the cavity will be driven to flow toward the air outlet 21 with increased pressure under the action of centrifugal force. When the gas hits the second baffle plate 51, the gas will be decelerated and pressurized. Finally, the air pressure in the second leakage chamber 20 is increased, and the pressure difference between the air outlet 21 and the second leakage chamber 20 is reduced, thereby reducing the gas leakage amount of the second leakage chamber 20.

[0067] Specifically, the disturbance of the gas in the cavity by the second rib 52 can increase the pressure gradient of the gas in the cavity, so that the thrust on the outer side of the wheel cover 2 is increased, that is, the second thrust is additionally applied to the outer side of the wheel cover 2, and the magnitude of the second thrust is adaptively changed according to the operating condition of the compressor, and is adjusted by the impeller speed. For example, when the axial force of the compressor points from the back side of the hub 1 to the outer side of the wheel cover 2, when the impeller speed increases, the air pressure at the air outlet 21 increases, and the axial force of the compressor increases. At this time, the air pressure in the second leakage cavity 20 also increases, and the second thrust increases, which helps to reduce the axial force of the centrifugal compressor.

[0068] Optionally, in addition to the impeller speed, the magnitude of the first thrust can be adjusted by designing the height, tilt direction or shape of the first baffle plate 41 and the first rib plate 42, and the magnitude of the second thrust can be adjusted by designing the height, tilt direction or shape of the second baffle plate 51 and the second rib plate 52.

[0069] Optionally, the first baffle 41 and the second baffle 51 may be arranged in a closed ring along the circumference, or may be arranged discontinuously along the circumference. Optionally, the first baffle 41 and the first rib 42 may be formed integrally with the hub 1, and the second baffle 51 and the second rib 52 may be formed integrally with the wheel cover 2 to reduce gas leakage. Optionally, the distance between the first baffle 41 and / or the second baffle 51 and the air outlet 21 is less than 0.7 times the radius.

[0070] Optionally, the first rib 42 may extend radially or in an arc shape in the gas flow direction, and the second rib 52 may extend along a radial plane or in an arc shape in the gas flow direction. Optionally, the top surface shape of the first rib 42 and the second rib 52 may be a rectangle or a twisted profile. Optionally, the number of the first ribs 42 is equal to the number of the second ribs 52, or the number of the first ribs 42 and the number of the second ribs 52 are both equal to the number of the blades 3.

[0071] Optionally, the height direction of the first baffle plate 41 may be along the axial direction, or along other directions that form an angle with the back end surface of the hub 1, such as an acute angle or an obtuse angle with the back end surface of the hub 1. Optionally, the height direction of the second baffle plate 51 may be along the axial direction, or along other directions that form an angle with the outer side of the wheel cover 2, such as perpendicular to the outer side of the wheel cover 2.

[0072] The first thrust and / or the second thrust of this embodiment can be adaptively changed according to the operating condition of the compressor, and can be changed according to the change of the impeller speed, so as to adaptively reduce the axial force of the centrifugal compressor, and further improve the reliability of the axial bearing and the reliability of the centrifugal compressor; the air pressure in the first leakage chamber 10 is increased by the cooperation of the first baffle plate 41 and the multiple first ribs 42, and the air pressure in the second leakage chamber 20 is increased by the cooperation of the second baffle plate 51 and the multiple second ribs 52, which can reduce the pressure difference between the air outlet 21 and the leakage chamber, improve the leakage resistance of the gas, and reduce the leakage amount of the gas.

[0073] In some embodiments, Figures 1 to 3 As shown, the height of the first baffle plate 41 is higher than the height of the first rib plate 42 ; and / or the height of the second baffle plate 51 is higher than the height of the second rib plate 52 .

[0074] Specifically, the height of the first baffle plate 41 is relatively high, which can enable the first baffle plate 41 to block the gas from the first rib plate 42, thereby reducing the speed and increasing the pressure of the gas in the first leakage chamber 10 and improving the leakage resistance of the gas, and can also enable the first baffle plate 41 to block the gas leaking from the impeller outlet 21 and directly reduce the leakage amount from the source; the height of the first rib plate 42 is relatively low, which can facilitate the flow of gas to do work on the gas in the first leakage chamber 10.

[0075] Specifically, the height of the second baffle plate 51 is relatively high, which can enable the second baffle plate 51 to block the gas from the second rib plate 52, thereby reducing the speed and increasing the pressure of the gas in the second leakage chamber 20 and improving the leakage resistance of the gas, and can also enable the second baffle plate 51 to block the gas leaking from the impeller outlet 21 and directly reduce the leakage amount from the source; the height of the second rib plate 52 is relatively low, which can facilitate the flow of gas to do work on the gas in the second leakage chamber 20.

[0076] In this embodiment, the height of the baffle plate is higher than the rib plate. The rib plate with a lower height can facilitate the flow of gas so that the rib plate can do work on the gas in the leakage chamber, thereby reducing the axial force of the centrifugal compressor; the baffle plate with a higher height can effectively block the gas on both sides, which can not only reduce the speed and increase the pressure of the gas in the leakage chamber, but also block the gas leakage from the air outlet 21, and can further reduce the gas leakage from different angles.

[0077] In some embodiments, Figures 1 to 3 As shown, the first baffle plate 41 and / or the second baffle plate 51 are in a circular ring shape.

[0078] This embodiment makes the first baffle plate 41 and / or the second baffle plate 51 in a circular ring shape, which can reduce local gas leakage compared to the arrangement method of circumferential spacing, and can reduce the speed and increase the pressure of the gas in the leakage cavity on the entire annular surface, thereby improving the uniformity of the first thrust and / or the second thrust; the baffle plate increases the gas leakage resistance on the entire annular surface, thereby reducing the gas leakage amount.

[0079] In some embodiments, Figures 1 to 3 As shown, the first ribs 42 extend in a radial direction and / or the second ribs 52 are located in a radial plane.

[0080] Specifically, the first rib 42 is located in a radial plane, and the central axis a is located in a plane where the second rib 52 is located.

[0081] By locating the ribs in the radial plane, this embodiment can make the gas in the leakage chamber hit the baffle tangentially, thereby improving the conversion efficiency of gas speed reduction and pressure increase, further increasing the gas pressure in the leakage chamber, and reducing the gas leakage while balancing the axial force; it can improve the gas flow characteristics and increase the efficiency of increasing the gas pressure in the leakage chamber when the ribs are doing work; it can reduce the difficulty of producing impellers containing ribs and reduce production costs.

[0082] In some embodiments,

[0083] The axial protrusion height of the first rib 42 is 0.4 to 0.6 times the axial dimension of the first leakage cavity 10; and / or

[0084] The axial protruding height of the second rib 52 is 0.4-0.6 times the axial dimension of the second leakage cavity 20 .

[0085] This embodiment can improve the gas flow characteristics in the leakage cavity by making the axial height of the rib plate 0.4 to 0.6 times the axial size of the corresponding leakage cavity, facilitate the gas flow in the leakage cavity so that the rib plate can do work on the gas in the leakage cavity, and reduce the gas leakage while balancing the axial force.

[0086] In some embodiments, Figure 3 As shown,

[0087] A first sealing portion is provided on the radial inner side of the first baffle plate 41, and the first sealing portion is radially located between the first stationary member 101 and the first baffle plate 41, and / or a second sealing portion is provided on the radial outer side of the first baffle plate 41, and the second sealing portion is radially located between the first stationary member 101 and the first baffle plate 41; and / or

[0088] A third sealing portion 511 is provided on the radial inner side of the second baffle plate 51, and the third sealing portion 511 is radially located between the second stationary part 102 and the second baffle plate 51, and / or a fourth sealing portion 512 is provided on the radial outer side of the second baffle plate 51, and the fourth sealing portion 512 is radially located between the second stationary part 102 and the second baffle plate 51.

[0089] Optionally, at least one of the first sealing portion, the second sealing portion, the third sealing portion 511 and the fourth sealing portion 512 may be a comb seal or the like.

[0090] This embodiment can improve the sealing effect by arranging sealing parts radially inside and outside the baffle, which can not only reduce the speed and increase the pressure of the gas in the leakage chamber, thereby increasing the pressure difference of the gas in the leakage chamber, but also block the gas leakage from the air outlet 21, and reduce the gas leakage while balancing the axial force.

[0091] In some embodiments, a fifth sealing portion 12 is disposed at the outlet of the first leakage cavity 10 , and / or a sixth sealing portion 22 is disposed at the outlet of the second leakage cavity 20 .

[0092] Optionally, the fifth sealing part 12 is generally arranged outside the first leakage cavity 10, including an interstage seal 121 or a secondary rear seal 122, etc. Optionally, the sixth sealing part 22 is generally arranged inside the second leakage cavity 20, including a primary front seal 221 or a secondary front seal 222, etc.

[0093] This embodiment can further prevent gas leakage and improve the energy efficiency of the centrifugal compressor by providing sealing parts at the outlet of the first leakage chamber 10 and the outlet of the second leakage chamber 20.

[0094] In some embodiments, Figure 4As shown, in the case where the centrifugal compressor is a two-stage compressor with an impeller placed at one end, if the impeller is a first-stage impeller 100, the first stationary part 101 is the return flow device 7, and the second stationary part 102 is the first-stage diffuser 61; if the impeller is a second-stage impeller 200, the first stationary part 101 is the compressor housing, and the second stationary part 102 is the second-stage diffuser 62.

[0095] Specifically, the two-stage compressor placed at one end of the impeller may also include a thrust bearing 8 and a thrust plate 9 for balancing the axial force, and the two can cooperate to reduce the axial force of the centrifugal compressor. Specifically, the first leakage chamber 10 is located between the back side of the hub 1 of the first-stage impeller 100 and the returner 7, or between the back side of the hub 1 of the second-stage impeller 200 and the compressor housing; the second leakage chamber 20 is located between the outer side of the wheel cover 2 of the first-stage impeller 100 and the first-stage diffuser 61, or between the outer side of the wheel cover 2 of the second-stage impeller 200 and the second-stage diffuser 62.

[0096] In this embodiment, when the centrifugal compressor is a two-stage compressor with one end of the impeller placed, by selectively arranging the first boost assembly 4 and the second boost assembly 5 on the first impeller 100 and the second impeller 200, it is possible to reduce gas leakage between the back side of the hub 1 of the first impeller 100 and the return flow device 7, or leakage between the back side of the hub 1 of the second impeller 200 and the compressor casing, or leakage between the outer side of the wheel cover 2 of the first impeller 100 and the first diffuser 61, or leakage between the outer side of the wheel cover 2 of the second impeller 200 and the second diffuser 62, thereby achieving both balancing the axial force and reducing gas leakage losses, thereby improving the operating performance of the centrifugal compressor.

[0097] In some embodiments, Figure 5 As shown, in the case where the centrifugal compressor is a two-stage compressor placed at both ends of the impeller, if the impeller is a first-stage impeller 100, the first stationary part 101 is a first-stage diffuser 61, and the second stationary part 102 is a first-stage volute 210; if the impeller is a second-stage impeller 200, the first stationary part 101 is a second-stage diffuser 62, and the second stationary part 102 is a second-stage volute 220.

[0098] Specifically, the two-stage compressor placed at both ends of the impeller may also include a motor barrel 300, a motor stator 400, a thrust bearing 8 and a thrust plate 9. The thrust bearing 8 and the thrust plate 9 cooperate to reduce the axial force of the centrifugal compressor. Specifically, the first leakage chamber 10 is located between the back side of the hub 1 of the first-stage impeller 100 and the first-stage diffuser 61, or between the back side of the hub 1 of the second-stage impeller 200 and the second-stage diffuser 62; the second leakage chamber 20 is located between the outer side of the wheel cover 2 of the first-stage impeller 100 and the first-stage volute 210, or between the outer side of the wheel cover 2 of the second-stage impeller 200 and the second-stage volute 220.

[0099] In this embodiment, when the centrifugal compressor is a two-stage compressor with impellers placed at both ends, by selectively arranging the first boost assembly 4 and the second boost assembly 5 on the first impeller 100 and the second impeller 200, it is possible to reduce gas leakage between the back side of the hub 1 of the first impeller 100 and the first diffuser 61, or leakage between the back side of the hub 1 of the second impeller 200 and the second diffuser 62, or leakage between the outer side of the wheel cover 2 of the first impeller 100 and the first volute 210, or leakage between the outer side of the wheel cover 2 of the second impeller 200 and the second volute 220, thereby achieving both balancing the axial force and reducing gas leakage losses, thereby improving the operating performance of the centrifugal compressor.

[0100] Secondly, the present disclosure proposes a refrigeration system, comprising the centrifugal compressor of the above embodiment.

[0101] In the refrigeration system of this embodiment, the centrifugal compressor can take into account both the balance of axial force and the reduction of gas leakage losses. The centrifugal compressor has high reliability and good operating performance, and the refrigeration system has high reliability and high operating efficiency.

[0102] In addition, the present disclosure also proposes an axial force balance design method for a centrifugal compressor based on the above embodiment, including:

[0103] Obtain the direction of the axial force during the operation of the centrifugal compressor;

[0104] The first supercharging assembly 4 and / or the second supercharging assembly 5 are arranged according to the direction of the axial force, so that the overall thrust formed by the first thrust and / or the second thrust is opposite to the direction of the axial force of the centrifugal compressor.

[0105] The axial force balancing design method of this embodiment can reduce the axial force of the centrifugal compressor, reduce the bearing capacity required for the axial bearing of the centrifugal compressor, reduce the wear of the working surface of the axial bearing, increase the service life of the axial bearing, and improve the reliability of the axial bearing and the reliability of the centrifugal compressor by making the overall thrust formed by the first thrust and / or the second thrust opposite to the axial force of the centrifugal compressor; at the same time, it can also avoid increasing the leakage gap at the seal due to balancing the axial force by increasing the balancing plate, etc., thereby achieving both balancing the axial force and reducing the gas leakage loss.

[0106] In some embodiments, the axial force balance design method further includes:

[0107] Get the magnitude of the axial force;

[0108] The first boosting assembly 4 and / or the second boosting assembly 5 are arranged according to the magnitude of the axial force, so that the magnitude of the overall thrust is consistent with the magnitude of the axial force.

[0109] The axial force balance design method of this embodiment can reduce the axial force to zero by making the magnitude of the overall thrust consistent with the magnitude of the axial force but opposite in direction, thereby further reducing the wear of the working surface of the axial bearing, increasing the service life of the axial bearing, and improving the reliability of the axial bearing and the reliability of the centrifugal compressor.

[0110] The centrifugal compressor and refrigeration system provided by the present disclosure are introduced in detail above. Specific embodiments are used in this article to illustrate the principles and implementation methods of the present disclosure. The description of the above embodiments is only used to help understand the method and core ideas of the present disclosure. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present disclosure, several improvements and modifications can be made to the present disclosure, and these improvements and modifications also fall within the scope of protection of the claims of the present disclosure.

Claims

1. A centrifugal compressor, characterized in that: The invention comprises a first stationary member (101), a second stationary member (102) and an impeller, wherein the impeller is rotatable about a central axis (a) and comprises: A wheel hub (1), wherein a first leakage chamber (10) is formed between a back end surface of the wheel hub (1) and the first stationary member (101); A wheel cover (2) is coaxially arranged with the wheel hub (1) and sleeved on the outer side of the wheel hub (1), wherein a second leakage chamber (20) is formed between the outer side of the wheel cover (2) and the second stationary member (102); A plurality of blades (3) are spaced apart and distributed along the circumference of the hub (1) and connected between the hub (1) and the wheel cover (2); and A first boosting assembly (4) and / or a second boosting assembly (5), wherein the first boosting assembly (4) is connected to the back end surface of the hub (1) and is configured to increase the air pressure in the first leakage chamber (10) during the rotation of the impeller, so as to additionally apply a first thrust to the back end surface of the hub (1); the second boosting assembly (5) is connected to the outer side of the wheel cover (2) and is configured to increase the air pressure in the second leakage chamber (20) during the rotation of the impeller, so as to additionally apply a second thrust to the outer side of the wheel cover (2); the overall thrust formed by the first thrust and / or the second thrust is opposite to the axial force of the centrifugal compressor.

2. The centrifugal compressor according to claim 1, characterized in that: The first supercharging assembly (4) comprises a first baffle plate (41) and a plurality of first rib plates (42), the first baffle plate (41) extending in the circumferential direction and being arranged radially outside the plurality of first rib plates (42), the plurality of first rib plates (42) being arranged at intervals in the circumferential direction, and the plurality of first rib plates (42) extending from an area close to the central axis (a) to an area close to the first baffle plate (41); and / or The second supercharging assembly (5) comprises a second baffle plate (51) and a plurality of second ribs (52); the second baffle plate (51) extends in a circumferential direction and is arranged in an area close to the air outlet (21) relative to the plurality of second ribs (52); the plurality of second ribs (52) are arranged at intervals in the circumferential direction; the plurality of second ribs (52) extend from an area close to the air inlet (11) to an area close to the first baffle plate (41).

3. The centrifugal compressor according to claim 2, characterized in that: The height of the first baffle plate (41) is higher than the height of the first rib plate (42); and / or The height of the second baffle plate (51) is higher than the height of the second rib plate (52).

4. The centrifugal compressor according to claim 2, characterized in that: The first baffle plate (41) and / or the second baffle plate (51) are in the shape of a ring.

5. The centrifugal compressor according to claim 2, characterized in that: The first rib (42) extends in the radial direction, and / or the second rib (52) is located in a radial plane.

6. The centrifugal compressor according to claim 2, characterized in that: The axial protrusion height of the first rib (42) is 0.4 to 0.6 times the axial dimension of the first leakage cavity (10); and / or The axial protruding height of the second rib plate (52) is 0.4 to 0.6 times the axial dimension of the second leakage cavity (20).

7. The centrifugal compressor according to claim 2, characterized in that: A first sealing portion is provided on the radial inner side of the first baffle plate (41), the first sealing portion being located radially between the first stationary member (101) and the first baffle plate (41); and / or a second sealing portion is provided on the radial outer side of the first baffle plate (41), the second sealing portion being located radially between the first stationary member (101) and the first baffle plate (41); and / or A third sealing portion (511) is provided on the radial inner side of the second baffle plate (51), and the third sealing portion (511) is radially located between the second stationary part (102) and the second baffle plate (51), and / or a fourth sealing portion (512) is provided on the radial outer side of the second baffle plate (51), and the fourth sealing portion (512) is radially located between the second stationary part (102) and the second baffle plate (51).

8. The centrifugal compressor according to any one of claims 1 to 7, characterized in that: A fifth sealing portion (12) is provided at the outlet of the first leakage chamber (10), and / or a sixth sealing portion (22) is provided at the outlet of the second leakage chamber (20).

9. The centrifugal compressor according to any one of claims 1 to 7, characterized in that: In the case where the centrifugal compressor is a two-stage compressor with an impeller placed at one end, if the impeller is a first-stage impeller (100), the first stationary part (101) is a return flow device (7), and the second stationary part (102) is a first-stage diffuser (61); if the impeller is a second-stage impeller (200), the first stationary part (101) is a compressor housing, and the second stationary part (102) is a second-stage diffuser (62).

10. The centrifugal compressor according to any one of claims 1 to 7, characterized in that: In the case where the centrifugal compressor is a two-stage compressor with an impeller placed at both ends, if the impeller is a first-stage impeller (100), the first stationary part (101) is a first-stage diffuser (61), and the second stationary part (102) is a first-stage volute (210); if the impeller is a second-stage impeller (200), the first stationary part (101) is a second-stage diffuser (62), and the second stationary part (102) is a second-stage volute (220).

11. A refrigeration system, characterized in that: Including the centrifugal compressor according to any one of claims 1 to 10.

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