CN218493838U

CN218493838U - Centrifugal compressor and air conditioning system

Info

Publication number: CN218493838U
Application number: CN202222831486.6U
Authority: CN
Inventors: 赵鹏飞; 曹成林; 高阳; 魏文鹏
Original assignee: Qingdao Hisense Hitachi Air Conditioning System Co Ltd
Current assignee: Qingdao Hisense Hitachi Air Conditioning System Co Ltd
Priority date: 2022-10-26
Filing date: 2022-10-26
Publication date: 2023-02-17
Anticipated expiration: 2032-10-26

Abstract

A centrifugal compressor and an air conditioning system relate to the technical field of compressors and are used for solving the problem that the working energy efficiency of a two-stage centrifugal compressor is reduced. The centrifugal compressor comprises a shell, a cavity is formed in the shell, and the multistage impeller, the reflux device, the reversing plate and the vaneless diffuser are all fixed in the cavity and form a diffusion channel, a reversing channel and a reflux channel; the reversing plate is arranged around the vaneless diffuser for one circle, and an air supply gap is formed between the reversing plate and the peripheral wall surface of the vaneless diffuser; an air supply channel surrounding the vaneless diffuser for one circle is formed on the reversing plate. The first end of the air replenishing gap is communicated with the air inlet of the reversing channel and is used for reducing air backflow of the air inlet of the reversing channel; the second end of the air supply gap is communicated with the air supply channel; the circumferential air inlet uniformity of the diffusion channel is realized by a tangential air inlet mode of the first air inlet pipe along the air supplementing channel.

Description

Centrifugal compressor and air conditioning system

Technical Field

The application relates to the field of centrifugal compressors, in particular to a centrifugal compressor and an air conditioning system.

Background

The air conditioner is generally internally provided with a two-stage centrifugal compressor which can pressurize a gaseous refrigerant flowing through the air conditioner, so that the refrigerating or heating efficiency of the air conditioner is ensured.

In the related art, the two-stage centrifugal compressor mainly includes a casing, a vaneless diffuser, a first-stage impeller, a reflux device and a second-stage impeller, wherein the vaneless diffuser, the first-stage impeller, the reflux device and the second-stage impeller are located inside the casing, a diffusion channel is formed between the vaneless diffuser and the reflux device, and an air inlet of the diffusion channel is communicated with an air outlet of the first-stage impeller, so that a high-speed gaseous refrigerant discharged from the first-stage impeller enters the diffusion channel and is converted into a low-speed high-pressure gaseous refrigerant, and first-stage compression of the gaseous refrigerant is achieved.

However, at the air outlet of the diffuser channel, the flow rate of the gaseous refrigerant decreases and the pressure increases, i.e., a pressure difference occurs between the air outlet and the air inlet of the diffuser channel, so that the gaseous refrigerant at the air outlet of the diffuser channel has a tendency to flow toward the air inlet of the diffuser channel, i.e., a backflow phenomenon occurs, and thus the flow of the gaseous refrigerant in the diffuser channel is blocked, thereby reducing the working energy efficiency of the two-stage centrifugal compressor.

Disclosure of Invention

The application provides a centrifugal compressor and an air conditioning system, which are used for solving the problem that the working energy efficiency of a double-stage centrifugal compressor is reduced.

In a first aspect, the present application provides a centrifugal compressor comprising a casing having a cavity formed therein; a multi-stage impeller, a vaneless diffuser and a reflux device which are coaxially arranged are fixed in the cavity; the multistage impeller comprises a first-stage impeller, a diffusion passage is formed between the vaneless diffuser and the reflux device, and an air outlet of the first-stage impeller is communicated with an air inlet of the diffusion passage; the reversing plate is arranged around the periphery of the vaneless diffuser and is fixedly connected with the shell, a reversing channel is formed between the reversing plate and the reflux device, and an air inlet of the reversing channel is communicated with an air outlet of the diffuser channel; an annular air supply gap is formed between the reversing plate and the peripheral wall surface of the vaneless diffuser; an air supply channel is formed on the reversing plate and surrounds the vaneless diffuser for one circle; a first air inlet pipe tangential to the circumferential direction of the air supplementing channel is formed on the outer wall of the shell; the first end of the air supply gap is communicated with the air inlet of the reversing channel and is used for reducing air backflow of the air inlet of the reversing channel; the second end of the air supply gap is communicated with the air supply channel; the air supply channel is communicated with the first air inlet pipe.

In some embodiments of the present application, a first groove is disposed on a surface of the commutating plate facing the vaneless diffuser, and the first groove surrounds the vaneless diffuser for a circle and forms the air supply passage with the vaneless diffuser.

In some embodiments of the present application, the air supply gap is formed between a surface of the notch of the first groove and the vaneless diffuser, and a second end of the air supply gap is communicated with the first groove.

In some embodiments of the present application, a first end of the first inlet conduit communicates with the air supplement passage, and a second end of the first inlet conduit flows into the air supplement gas.

In some embodiments of the present application, along a flowing direction of gas in the air supplement passage, an air intake area of the air supplement passage is gradually reduced, and the first end of the first air intake pipe is communicated with a position where the air intake area of the air supplement passage is maximum.

In some embodiments of the present application, the inlet area of the makeup passage is gradually changed in an equal or variable ratio.

In some embodiments of the present application, the diverter plate is integrally formed with the housing.

The application provides a centrifugal compressor, low pressure gaseous state refrigerant can get into the one-level impeller in through the air intake of one-level impeller to under the effect of one-level impeller, change into fast-speed gaseous state refrigerant into, and get into the diffusion passageway from the air outlet of one-level impeller in, in the diffusion passageway, fast-speed gaseous state refrigerant can turn into the high-pressure gaseous state refrigerant of low-speed, and enter into and trade in the passageway, with this realization one-level compression.

Because the air supply gap is formed between the reversing plate and the vaneless diffuser, an external gaseous refrigerant can be introduced into an air inlet (an air outlet of the diffusion channel) of the reversing channel through the air supply gap to drive the gaseous refrigerant at the air inlet of the reversing channel to flow along the reversing channel, so that the backflow phenomenon at the position is improved, the gaseous refrigerant can smoothly flow in the diffusion channel and the reversing channel, and the energy efficiency of the multistage centrifugal compressor is improved.

The air supply gap surrounds the vaneless diffuser for one circle. Therefore, along the circumferential direction of the vaneless diffuser, the gaseous refrigerant can enter the air outlet of the diffusion channel, and the energy efficiency of the multistage centrifugal compressor can be better improved. An air supply channel is formed on the reversing plate, surrounds the vaneless diffuser for one circle, is communicated with the second end of the air supply gap, and is communicated with an external gaseous refrigerant. The air duct is formed on the reversing plate, and the annular air supply gap is supplied with air by utilizing the annular air duct, so that the design is simplified. The first air inlet pipe of the multistage centrifugal compressor is fixed on the outer wall of the shell and is tangent to the circumferential direction of the air channel, the first end of the first air inlet pipe is communicated with the air channel, and the second end of the first air inlet pipe is communicated with an external gaseous refrigerant; along the flowing direction of gaseous refrigerant in the air duct, the ventilation cross-sectional area of air duct reduces gradually, and the first end of first intake pipe communicates in the biggest department of the ventilation cross-sectional area in air duct. And the circumferential air inlet uniformity of the diffusion channel is realized by utilizing tangential air inlet.

In a second aspect, the present application further provides an air conditioning system, comprising a condenser, an evaporator, an economizer and the above-mentioned centrifugal compressor, wherein the economizer is connected between the condenser and the evaporator through a connecting pipeline; the economizer is communicated with the first air inlet pipe. An economizer is used for providing gaseous refrigerants for the multistage centrifugal compressor, so that air and enthalpy of the system are supplemented, and the energy efficiency and the efficiency of the multistage centrifugal compressor are improved.

Drawings

The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the example serve to explain the principles of the invention and not to limit the invention.

Fig. 1 is a schematic diagram of a first external structure of an air conditioning system according to an embodiment of the present application;

fig. 2 is a schematic diagram of a second external structure of an air conditioning system according to an embodiment of the present application;

fig. 3 is an external schematic structural view illustrating an internal refrigerant flow of the air conditioning system in the cooling mode according to the embodiment of the present disclosure;

FIG. 4 is a schematic cross-sectional view of a multi-stage centrifugal compressor in the related art;

FIG. 5 is a schematic diagram showing a simulation of a multi-stage centrifugal compressor in the related art;

FIG. 6 is an exploded schematic view of a multi-stage centrifugal compressor provided in an embodiment of the present application;

FIG. 7 is a first schematic cross-sectional view of a multistage centrifugal compressor provided in accordance with an embodiment of the present application;

FIG. 8 is an enlarged view of a portion of FIG. 7 at A;

FIG. 9 is a schematic diagram illustrating a simulation of a multi-stage centrifugal compressor provided in an embodiment of the present application;

fig. 10 is a schematic external structural diagram of a housing according to an embodiment of the present application;

FIG. 11 is a schematic diagram of an external structure of an air conditioning system with an economizer according to an embodiment of the present application;

FIG. 12 is a second schematic cross-sectional view of a multistage centrifugal compressor provided in accordance with an embodiment of the present application;

FIG. 13 is a third schematic cross-sectional view of a multistage centrifugal compressor provided in accordance with an embodiment of the present application;

fig. 14 is a schematic view of a first external structure of a multistage centrifugal compressor according to an embodiment of the present application;

fig. 15 is a sixth cross-sectional schematic view of a multistage centrifugal compressor provided in an embodiment of the present application.

Reference numerals: 10-an air conditioning system; 100-indoor unit; 110-a first housing; 120-a first heat exchanger; 121-an evaporator; 200-outdoor unit; 210-a second housing; 220-a second heat exchanger; 221-a condenser; 230-multistage centrifugal compressor; 231-a housing; 2311-opening; 232-vaneless diffuser; 233-first-stage impeller; 234-reflux; 235-a secondary impeller; 236-a separator; 237-a reverser plate; 2371-first groove; 238-a first inlet line; 239-a second intake pipe; 23A-a diffuser channel; 23B-a commutation channel; 23C-a return channel; 23D-air supplement clearance; 240-an economizer; 241-an electronic expansion valve; 250-passage for replenishing Qi.

Detailed Description

The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only some embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that all directional indicators (such as up, down, left, right, front, and back \8230;) in the embodiments of the present invention are only used to explain the relative positional relationship between the components, the motion situation, etc. in a specific posture (as shown in the attached drawings), and if the specific posture is changed, the directional indicators are changed accordingly.

The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless otherwise specified.

In the description of the present application, it is to be noted that the terms "connected" and "connected" are to be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected, unless explicitly stated or limited otherwise. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art. In addition, when a pipeline is described, the terms "connected" and "connecting" are used in this application to mean conducting. The specific meaning is to be understood in conjunction with the context.

In the embodiments of the present application, words such as "exemplary" or "for example" are used to mean serving as an example, instance, or illustration. Any embodiment or design described herein as "exemplary" or "e.g.," is not necessarily to be construed as preferred or advantageous over other embodiments or designs. Rather, use of the word "exemplary" or "such as" is intended to present concepts related in a concrete fashion.

An air conditioner is widely used in daily life as a device for adjusting indoor temperature. Based on this, as shown in fig. 1, the present application provides an air conditioning system 10, which includes an outdoor unit 200 and an indoor unit 100, wherein the outdoor unit 200 is communicated with the indoor unit 100, and the outdoor unit 200 and the indoor unit 100 cooperate with each other to adjust the indoor temperature.

Specifically, as shown in fig. 2, the indoor unit 100 includes a first casing 110 and a first heat exchanger 120, the first heat exchanger 120 is disposed inside the first casing 110, the outdoor unit 200 includes a second casing 210, a second heat exchanger 220 and a multistage centrifugal compressor 230, the second heat exchanger 220 and the multistage centrifugal compressor 230 are disposed inside the second casing 210, and the first heat exchanger 120, the second heat exchanger 220 and the multistage centrifugal compressor 230 are sequentially communicated to regulate and control the indoor temperature.

The multistage centrifugal compressor 230 is generally a two-stage centrifugal compressor, and the two-stage centrifugal compressor can compress the gaseous refrigerant entering the multistage centrifugal compressor twice, so that the gaseous refrigerant can be sufficiently compressed, and the smooth cooling or heating of the air conditioning system 10 can be ensured.

Illustratively, as shown in fig. 3, during cooling in summer, the first heat exchanger 120 serves as an evaporator 121, the second heat exchanger 220 serves as a condenser 221, an air inlet of the multistage centrifugal compressor 230 communicates with an air outlet of the evaporator 121, an air outlet of the multistage centrifugal compressor 230 communicates with an air inlet of the condenser 221, and an air outlet of the condenser 221 communicates with an air inlet of the evaporator 121.

Through the above arrangement, the liquid refrigerant entering the evaporator 121 can absorb indoor heat, so that the indoor temperature is reduced, refrigeration is realized, meanwhile, the liquid refrigerant can be converted into a gaseous refrigerant due to heat absorption, then the gaseous refrigerant is discharged from the outlet of the evaporator 121 and enters the multistage centrifugal compressor 230, in the multistage centrifugal compressor 230, the gaseous refrigerant is compressed into a high-pressure gaseous refrigerant, then the gaseous refrigerant is discharged to the condenser 221 from the outlet of the multistage centrifugal compressor 230, in the condenser 221, the gaseous refrigerant is condensed to release heat, the heat is discharged to the outdoor space, meanwhile, the gaseous refrigerant is converted into the liquid refrigerant, and the gaseous refrigerant enters the evaporator 121 again, so that the circulation is realized, and indoor continuous refrigeration is realized.

Specifically, as shown in fig. 4, in order to compress a gaseous refrigerant entering the multistage centrifugal compressor 230, in the related art, a multistage centrifugal compressor 230 is provided, where the multistage centrifugal compressor 230 includes a casing 231, a vaneless diffuser 232, a first-stage impeller 233, a return device 234, and a second-stage impeller 235, the vaneless diffuser 232, the first-stage impeller 233, the return device 234, and the second-stage impeller 235 are sequentially installed in the casing 231, and a diffusion channel 23A, a reversing channel 23B, and a return channel 23C are sequentially formed between the vaneless diffuser 232, the return device 234, and the casing 231, where an air inlet of the diffusion channel 23A is communicated with an air outlet of the first-stage impeller 233, an air outlet of the return channel 23C is communicated with an air inlet of the second-stage impeller 235, and the reversing channel 23B is communicated between the diffusion channel 23A and the return channel 23C.

Through the above arrangement, the gaseous refrigerant discharged from the air outlet of the first-stage impeller 233 can sequentially pass through the diffusion channel 23A, the reversing channel 23B, and the backflow channel 23C and enter the second-stage impeller 235, and is finally discharged to the outside of the casing 231, and in the process that the gaseous refrigerant passes through the first-stage impeller 233 and the second-stage impeller 235, the first-stage impeller 233 and the second-stage impeller 235 rotate and compress the gaseous refrigerant by using a centrifugal force during the rotation process, so as to obtain a high-pressure gaseous refrigerant.

It can be understood that the vaneless diffuser 232 functions to convert kinetic energy of the gaseous refrigerant discharged from the first-stage impeller 233 into pressure energy to more fully compress the gaseous refrigerant. The function of the backflow device 234 is to rectify the gaseous refrigerant discharged from the air outlet of the primary impeller 233, so that the gaseous refrigerant can enter the secondary impeller 235 from the air inlet of the secondary impeller 235, thereby implementing secondary compression of the gaseous refrigerant.

However, because in the diffuser channel 23A, the kinetic energy of the gaseous refrigerant is converted into static pressure energy, as shown in fig. 5, so the flow velocity of the gaseous refrigerant at the air outlet position of the diffuser channel 23A is reduced, the pressure is raised, i.e., a pressure difference phenomenon occurs between the air outlet and the air inlet of the diffuser channel 23A, so the gaseous refrigerant at the air outlet of the diffuser channel 23A has a tendency of flowing towards the air inlet of the diffuser channel 23A, i.e., a backflow phenomenon occurs, so the flow of the gaseous refrigerant in the diffuser channel 23A is blocked, and thus the working energy efficiency of the multistage centrifugal compressor 230 is reduced.

In order to solve the above problems, as shown in fig. 6, the multistage centrifugal compressor 230 provided by the present application includes a compressor assembly, a first-stage impeller 233, and a second-stage impeller 235, wherein the compressor assembly includes a casing 231, a backflow device 234, and a vaneless diffuser 232, and a cavity is formed inside the casing 231; as shown in fig. 7, the return 234 and vaneless diffuser 232 are fixed within the cavity; the first-stage impeller 233 is rotatably arranged in the cavity, the vaneless diffuser 232 and the return device 234 are respectively positioned on two sides of the first-stage impeller 233 along the axial direction of the first-stage impeller, a diffusion passage 23A is formed between the vaneless diffuser 232 and the return device 234, and an air outlet of the first-stage impeller 233 is communicated with an air inlet of the diffusion passage 23A; the air inlet of the primary impeller 233 is communicated with the air outlet of the evaporator 121; the partition plate 236 is fixed in the cavity and is positioned on one side of the return device 234 far away from the vaneless diffuser 232, the partition plate 236 is arranged around the axis of the first-stage impeller 233 in a circle and forms a return channel 23C with the return device 234, and an air inlet of the return channel 23C is communicated with an air outlet of the reversing channel 23B; the second-stage impeller 235 is rotatably disposed in the cavity and located between the partition 236 and the return channel 234, an air outlet of the return channel 23C is communicated with an air inlet of the second-stage impeller 235, and an air outlet of the second-stage impeller 235 is communicated with the condenser 221.

As shown in fig. 7, the compressor assembly further includes a reversing plate 237, the reversing plate 237 is fixed in the cavity and is disposed around the vaneless diffuser 232, as shown in fig. 8, an air replenishing gap 23D is formed between the reversing plate 237 and the peripheral wall surface of the vaneless diffuser 232, one side edge of the reversing plate 237 close to the backflow device 234 extends in a direction close to the backflow device 234, a reversing channel 23B is formed between the reversing plate and the backflow device 234, and an air inlet of the reversing channel 23B is communicated with an air outlet of the diffuser channel 23A; the first end of the air supply gap 23D is communicated with the air inlet of the reversing channel 23B, and the second end of the air supply gap 23D is used for being communicated with the external gaseous refrigerant.

As shown in fig. 7, the low-pressure gaseous refrigerant discharged from the evaporator 121 can enter the first-stage impeller 233 through the air inlet of the first-stage impeller 233, and is converted into a high-speed gaseous refrigerant by the first-stage impeller 233, and enters the diffuser passage 23A from the air outlet of the first-stage impeller 233, and the high-speed gaseous refrigerant is converted into a low-speed high-pressure gaseous refrigerant in the diffuser passage 23A, and enters the switching passage 23B, thereby achieving first-stage compression. After passing through the reversing channel 23B, the gaseous refrigerant turns to enter the return channel 23C, and enters the secondary impeller 235 through the return channel 23C, and is compressed in the second stage under the action of the secondary impeller 235, and finally discharged to the condenser 221 from the air outlet of the secondary impeller 235, so that the gaseous refrigerant discharged from the evaporator 121 is compressed.

As shown in fig. 8, since the direction changing plate 237 and the peripheral wall surface of the vaneless diffuser 232 have the air supply gap 23D therebetween, as shown in fig. 9, the external gaseous refrigerant may be introduced into the air inlet of the direction changing channel 23B through the air supply gap 23D to drive the gaseous refrigerant at the air outlet (the air inlet of the direction changing channel 23B) of the diffuser channel 23A to flow along the direction changing channel 23B, so as to improve the backflow phenomenon therein, so that the gaseous refrigerant can smoothly flow in the diffuser channel 23A and the direction changing channel 23B, thereby improving the energy efficiency of the multistage centrifugal compressor 230.

It can be understood that the first-stage impeller 233, the vaneless diffuser 232, the backflow device 234, the second-stage impeller 235 and the partition 236 are coaxially arranged, and the first-stage impeller 233 and the second-stage impeller 235 are rotated by arranging a rotating shaft in the cavity, passing the rotating shaft through the first-stage impeller 233, the vaneless diffuser 232, the backflow device 234, the second-stage impeller 235 and the partition 236 in sequence, and driving the rotating shaft to rotate by using a motor.

In order to communicate the air inlet of the first-stage impeller 233 with the air outlet of the evaporator 121, as shown in fig. 10, an opening 2311 is formed in the housing 231, the opening 2311 is communicated with the cavity, the vaneless diffuser 232 is fixed in the cavity, the air inlet of the vaneless diffuser 232 is communicated with the air outlet of the evaporator 121 through the opening 2311, the first-stage impeller 233 is disposed at the air inlet of the vaneless diffuser 232, and the first-stage impeller 233 is communicated with the air outlet of the evaporator 121 through the air inlet of the vaneless diffuser 232.

Of course, the duct may also be directly passed through the side wall of the casing 231, such that the first end of the duct is communicated with the air inlet of the vaneless diffuser 232, and thus the first end of the duct is communicated with the air inlet of the primary impeller 233, and the second end of the duct is communicated with the air outlet of the evaporator 121.

In addition, as shown in fig. 11, the outdoor unit 200 further includes an economizer 240, and the economizer 240 is connected to a second end of the gas replenishing gap 23D. The economizer 240 is used to supply gaseous refrigerant to the make-up air gap 23D.

Since the gaseous refrigerant discharged from the economizer 240 is a low-temperature gaseous refrigerant, the low-temperature gaseous refrigerant is discharged into the switching path 23B, so that the multistage centrifugal compressor 230 can be replenished with air, the operating temperature of the multistage centrifugal compressor 230 can be reduced, and the operating efficiency of the multistage centrifugal compressor 230 can be improved.

Of course, a separate device may be provided to supply the gaseous refrigerant.

Exemplarily, when the economizer 240 is a heat exchange type economizer, in order to supply a gaseous refrigerant by using the economizer 240, as shown in fig. 11, the economizer 240 is connected between the evaporator 121 and the condenser 221, a first inlet of the economizer 240 is communicated with a liquid outlet of the condenser 221 through a connecting pipe, a first bypass is connected between the condenser 221 and the economizer 240, one end of the first bypass is communicated with the connecting pipe, the other end of the first bypass is communicated with a second inlet of the economizer 240, a first outlet of the economizer 240 is communicated with a liquid inlet of the evaporator 121, and a second outlet of the economizer 240 is communicated with a second end of the gas replenishing gap 23D; an electronic expansion valve 241 is provided between the connection point of the connection pipe to the first bypass branch and the second inlet of the economizer 240.

In this way, the flow rate of the refrigerant entering the economizer 240 through the first inlet of the economizer 240 can be controlled by adjusting the electronic expansion valve 241, so that the refrigerant entering the economizer 240 through the first inlet exchanges heat with the refrigerant entering the economizer 240 through the second inlet, and the low-temperature gaseous refrigerant discharged from the second outlet of the economizer 240 can enter the reversing channel 23B through the gas supplementing gap 23D because the second outlet of the economizer 240 is communicated with the second end of the gas supplementing gap 23D. Thereby improving the backflow phenomenon at the air outlet of the diffusion channel 23A (the air inlet of the reversing channel 23B), and realizing air supply and enthalpy increase, so as to improve the energy efficiency of the multistage centrifugal compressor 230 and improve the efficiency thereof.

Although the economizer 240 can be of other types.

On the basis, as shown in fig. 8, the gas supply gap 23D is disposed around the vaneless diffuser 232 for a circle, so that the external gaseous refrigerant can enter the reversing channel 23B from the air outlet of the diffuser channel 23A through the annular gas supply gap 23D, and thus, each air inlet of the reversing channel 23B can enter the gaseous refrigerant along the circumferential direction of the vaneless diffuser 232, so as to improve the backflow condition at each air outlet of the diffuser channel 23A along the circumferential direction of the vaneless diffuser 232, thereby better improving the energy efficiency of the multistage centrifugal compressor 230.

Alternatively, the air supply gap 23D may surround a portion of the vaneless diffuser 232 in the circumferential direction of the vaneless diffuser 232.

On the basis, in order to facilitate the gaseous refrigerant from the outside to enter the air supply gap 23D, as shown in fig. 12, an air supply passage 250 is formed on the compressor component, the air supply passage 250 surrounds the vaneless diffuser 232 for a circle and is communicated with the second end of the air supply gap 23D, and the air supply passage 250 is communicated with the gaseous refrigerant from the outside.

In this way, the external gaseous refrigerant can enter the gas supplementing channel 250, and since the gas supplementing channel 250 is disposed around the vaneless diffuser 232 for one circle, the gaseous refrigerant can surround the vaneless diffuser 232 for one circle, and since the gas supplementing channel 250 is communicated with the second end of the gas supplementing gap 23D, and the gas supplementing gap 23D is the annular gas supplementing gap 23D, the gaseous refrigerant in the gas supplementing channel 250 can enter the reversing channel 23B through the gas supplementing gap 23D.

Due to the existence of the gas supplementing channel 250, when the gaseous refrigerant is introduced, the gaseous refrigerant does not need to be directly introduced into the second end of the annular gas supplementing gap 23D, an annular gas inlet pipeline does not need to be arranged to be communicated with the second end of the annular gas supplementing gap 23D, and only an opening communicated with the outside of the air duct needs to be formed in the wall of the gas supplementing channel 250, so that the opening is communicated with the external gaseous refrigerant, the processing can be simplified, and the installation and the communication of the external gaseous refrigerant are facilitated.

In some embodiments, to form the air supply channel 250, as shown in fig. 13, the casing 231 is fixedly connected to the reversing plate 237, a first groove 2371 is formed on a surface of the reversing plate 237 facing the vaneless diffuser 232, the first groove 2371 surrounds the vaneless diffuser 232 for a circle and forms the air supply channel 250 with the vaneless diffuser 232, the air supply gap 23D is formed between a surface where a notch of the first groove 2371 is located and the vaneless diffuser 232, and a second end of the air supply gap 23D is communicated with the first groove 2371.

By forming the first groove 2371 on the direction changing plate 237 and forming the air supply passage 250 by using the first groove 2371 and the vaneless diffuser 232, the air supply gap 23D is formed between the surface of the first groove 2371 and the vaneless diffuser 232, and the second end of the air supply gap 23D is communicated with the first groove 2371, so that the external gaseous refrigerant can enter the first groove 2371 and finally enter the direction changing passage 23B through the air supply gap 23D.

It can be understood that the air supply gap 23D formed between the plane of the notch of the first groove 2371 and the vaneless diffuser 232 means that the air supply gap 23D is formed between the portion of the surface of the notch of the first groove 2371, which is close to the side of the backflow device 234, and the vaneless diffuser 232, so that the air supply gap 23D is communicated between the first groove 2371 and the air inlet of the commutation passage 23B.

The housing 231 and the reversing plate 237 are fixedly connected and can be integrally formed, the housing 231 and the reversing plate 237 are higher in structural strength, and in addition, the housing 231 and the reversing plate 237 can be processed at one time without secondary processing. Of course, the housing 231 and the reversing plate 237 may be separate structures, and the housing 231 and the reversing plate 237 are processed respectively, and then are processed for the second time, so that the difficulty in processing the housing 231 and the reversing plate 237 can be reduced.

On this basis, in order to enable the gaseous refrigerant entering the gas supplementing channel 250 to uniformly enter the reversing channel 23B through the gas supplementing gap 23D along a circle of the gas supplementing channel 250, as shown in fig. 14, the multistage centrifugal compressor 230 further includes a first gas inlet pipe 238, the first gas inlet pipe 238 is fixed on the outer wall of the casing 231, as shown in fig. 15, the first gas inlet pipe 238 is tangential to the gas supplementing channel 250 in the circumferential direction, a first end of the first gas inlet pipe 238 is communicated with the gas supplementing channel 250, and a second end of the first gas inlet pipe 238 is communicated with the external gaseous refrigerant; along the flowing direction of the gaseous refrigerant in the air supplement channel 250, the ventilation cross-sectional area of the air supplement channel 250 is gradually reduced, and the first end of the first air inlet pipe 238 is communicated with the position where the ventilation cross-sectional area of the air supplement channel 250 is maximum.

Since the first inlet pipe 238 is tangential to the gas supply passage 250 in the circumferential direction, the gaseous cooling medium entering the first inlet pipe 238 can enter the gas supply passage 250 through the first inlet pipe 238 in the direction tangential to the gas supply passage 250, and flow clockwise or counterclockwise (clockwise in fig. 15) along the gas supply passage 250.

And because along the flow direction of gaseous refrigerant in the air supply channel 250, the ventilation cross-sectional area of the air supply channel 250 is gradually reduced, so that in the flowing process of the gaseous refrigerant, the pressure of the gaseous refrigerant is gradually increased, the problem that the pressure of the gaseous refrigerant can be gradually reduced along with the flowing of the gaseous refrigerant can be solved, the gaseous refrigerant can uniformly enter the air supply gap 23D in the circumferential direction of the diffuser, the circumferential air inlet uniformity of the reversing channel 23B is ensured, and the backflow phenomenon at the air inlet of the reversing channel 23B is better improved.

In order to better achieve uniformity of circumferential air intake, the cross-sectional area of the air supply channel 250 is reduced in equal proportion along the flow direction of the gaseous refrigerant in the air supply channel 250. That is, the flow rate is reduced by a fixed ratio, and in order to determine the ratio, the flow rate may be determined according to the wind resistance of the gas supplementing channel 250, or may be determined according to the initial velocity of the gaseous refrigerant entering the gas supplementing channel 250 and the maximum ventilation cross-sectional area of the gas supplementing channel 250. Or may be determined by integrating the data.

Of course, the sectional area of the air supply channel 250 may also be reduced at a variable ratio along the flowing direction of the gaseous refrigerant in the air supply channel 250.

For example, when the air supplement channel 250 is composed of the first groove 2371 and the reversing plate 237, in order to make the first air inlet pipe 238 tangent to the circumference of the air supplement channel 250, as shown in fig. 13, the first air inlet pipe 238 is tangent to the circumference of the first groove 2371 and tangent to the side of the casing 231 where the bottom of the first groove 2371 is located. In this way, the external gaseous refrigerant can enter the first groove 2371 through the first inlet tube 238, and is discharged from the notch of the first groove 2371 to the air supplement gap 23D, and finally enters the reversing channel 23B.

The above description is only an embodiment of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions within the technical scope disclosed in the present application should be covered within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A centrifugal compressor, comprising:

a housing having a cavity formed therein;

a multi-stage impeller, a vaneless diffuser and a reflux device which are coaxially arranged are fixed in the cavity;

the multistage impeller comprises a first-stage impeller, a diffusion passage is formed between the vaneless diffuser and the reflux device, and an air outlet of the first-stage impeller is communicated with an air inlet of the diffusion passage;

the reversing plate is coaxially arranged around the vaneless diffuser and is fixedly connected with the machine shell, a reversing channel is formed between the reversing plate and the reflux device, and an air inlet of the reversing channel is communicated with an air outlet of the diffuser channel;

an annular air supplementing gap is formed between the reversing plate and the peripheral wall surface of the vaneless diffuser along the axial direction of the primary impeller; the reversing plate surrounds the vaneless diffuser for one circle to form an air supplementing channel; the first end of the air supply gap is communicated with the air inlet of the reversing channel and is used for reducing air backflow of the air inlet of the reversing channel; the second end of the air supply gap is communicated with the air supply channel;

a first air inlet pipe tangential to the circumferential direction of the air supplementing channel is formed on the outer wall of the shell along the circumferential direction of the primary impeller; the air supply channel is communicated with the first air inlet pipe.

2. The centrifugal compressor of claim 1, wherein a surface of the reversing plate facing the vaneless diffuser is provided with a first groove, and the first groove surrounds the vaneless diffuser for a circle and forms the air supply passage with the vaneless diffuser.

3. The centrifugal compressor of claim 2, wherein the air-supply gap is formed between a surface of the first groove where the notch is located and the vaneless diffuser, and a second end of the air-supply gap communicates with the first groove.

4. The centrifugal compressor of claim 2, wherein a first end of the first inlet tube is in communication with the make-up air passage and a second end of the first inlet tube is filled with make-up air.

5. The centrifugal compressor according to claim 4, wherein the air inlet area of the air supply passage is gradually reduced along the flow direction of the gas in the air supply passage, and the first end of the first air inlet pipe is communicated with the position where the air inlet area of the air supply passage is maximum.

6. The centrifugal compressor of claim 5, wherein the air make-up passage air intake area varies gradually in equal or varying proportions.

7. The centrifugal compressor according to any one of claims 1 to 6, wherein the reversing plate is integrally formed with the casing.

8. An air conditioning system, characterized in that it comprises a centrifugal compressor according to any one of claims 1 to 7.

9. The air conditioning system of claim 8, further comprising a condenser, an evaporator, and an economizer connected intermediate the condenser and the evaporator by a connecting duct; the economizer is communicated with the first air inlet pipe and used for supplementing gaseous refrigerants to the centrifugal compressor.

10. The air conditioning system of claim 9, wherein the economizer is provided with a first bypass passage, one end of the first bypass passage being communicated with an outlet of the condenser, and the other end of the first bypass passage being communicated with the first intake pipe.