Compressor and method of designing a compressor

Abstract

The embodiment of the application discloses a kind of compressor and the design method of compressor, the compressor provided in the application includes compressor main body, gas taking assembly, sealing interstage, wherein, compressor main body includes multiple impellers, multiple impellers are set in the air outlet of compressor main body using the way of multistage series;Gas taking end of gas taking assembly is set between two adjacent impellers, and gas taking assembly includes flow guide pipe;Sealing interstage is set at the shaft end of the last stage impeller of compressor main body, and sealing interstage is communicated with the gas outlet end of flow guide pipe;Realize that the position of sealing gas is moved forward, and the temperature and pressure of the process gas used are lower than the outlet gas, which reduces the temperature and pressure of the sealing gas, improves the safety of the product without using better high-temperature and high-pressure dry gas sealing material, prolongs the service life of the product under the premise of saving a large amount of cost.

Description

Technical Field

[0001] This application relates to the field of centrifugal compressor technology, and more particularly to a compressor and a compressor design method. Background Technology

[0002] Dry gas seals, as a type of non-contact seal, have excellent sealing performance and have been widely used in centrifugal compressor units in recent years. For centrifugal compressor units with particularly high pressure, toxic, flammable and explosive media, in order to ensure zero leakage, series dry gas seals are mainly used as shaft end seals of centrifugal compressors. In order to prevent changes in the composition of the internal medium of the compressor, this type of dry gas seal generally uses the process gas from the outlet of the centrifugal compressor as the main sealing gas.

[0003] However, as petrochemical production scale continues to expand and chemical processes become increasingly complex, the design requirements for centrifugal compressors are also becoming more and more stringent. Sometimes, the compressor outlet gas pressure and temperature are too high. The traditional method of taking gas from the centrifugal compressor outlet as the main sealing gas for dry gas sealing may exceed the tolerance of conventional dry gas sealing materials due to excessive pressure and temperature, and thus fail to meet the design requirements. If better high-temperature and high-pressure dry gas sealing materials are used and the pressure design level of the sealing gas pipeline is increased, it will bring huge procurement and design costs. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0005] Therefore, a first aspect of the present invention provides a compressor.

[0006] A second aspect of the present invention provides a method for designing a compressor.

[0007] In view of this, a compressor is provided according to a first aspect of the embodiments of this application, comprising:

[0008] Compressor body;

[0009] The compressor body includes multiple impellers, which are arranged in a multi-stage series at the air outlet of the compressor body.

[0010] A gas intake assembly, wherein the gas intake end of the gas intake assembly is disposed between two adjacent impeller stages, and the gas intake assembly includes a guide pipe;

[0011] The sealing stage is located at the shaft end of the last stage of the impeller in the compressor body, and the sealing stage is connected to the outlet end of the guide pipe.

[0012] In one feasible implementation, the compressor body further includes:

[0013] Centrifugal compressor casing;

[0014] a partition plate, the partition plate being arranged between every two adjacent impellers.

[0015] In an embodiment, the compressor body further comprises:

[0016] a centrifugal compressor casing;

[0017] a partition plate, the partition plate being arranged between every two adjacent impellers.

[0018] In an embodiment, the compressor body further comprises:

[0019] a communication pipe, the communication pipe being a bend pipe, the communication pipe being arranged between every two adjacent impellers for connecting the two adjacent impellers.

[0020] a diffuser, the diffuser being arranged in the communication pipe.

[0021] In an embodiment, the gas taking assembly comprises:

[0022] a gas taking pipe, the gas taking port of the gas taking pipe being arranged along the tangential direction of the communication pipe and being connected to the flow guide pipe.

[0023] In an embodiment, the gas taking assembly further comprises:

[0024] a gas taking volute, the gas taking volute being arranged between the gas taking pipe and the flow guide pipe, the gas taking volute being arranged inside the partition plate.

[0025] According to a second aspect of the embodiments of the present application, a design method of a compressor is provided, which is used for designing the compressor as described above, and the design method of the compressor comprises:

[0026] confirming position information of a gas taking point;

[0027] determining theoretical value information of a minimum pipe diameter of a gas taking end of a gas taking assembly based on the position information;

[0028] determining parameters of the gas taking assembly based on the theoretical value information.

[0029] In an embodiment, the step of confirming the position information of the gas taking point comprises:

[0030] selecting a preselected gas taking point between any two impellers;

[0031] obtaining process gas temperature and pressure information of all preselected gas taking points according to the through flow of the centrifugal compressor;

[0032] The process gas temperature and pressure information is lower than the pre-selected gas extraction point of the tolerance temperature and pressure of the shaft end sealing material.

[0033] In an embodiment, the step of determining the theoretical value information of the minimum pipe diameter of the gas extraction end of the gas extraction assembly based on the position information comprises:

[0034] A turbulent flow model is established at the gas extraction end of the gas extraction assembly and the gas outlet end of the guide pipe.

[0035] The pressure and flow rate at the gas extraction end of the gas extraction assembly are obtained through the flow of the centrifugal compressor.

[0036] The theoretical value information of the minimum pipe diameter of the gas extraction end of the gas extraction assembly is determined based on the pressure and flow rate at the gas extraction end of the gas extraction assembly and the design value of the required gas supply amount of the shaft end sealing chamber.

[0037] In an embodiment, the step of determining the parameters of the gas extraction assembly based on the theoretical value information comprises:

[0038] The reliability of the gas extraction assembly is determined based on the theoretical value information, and the parameters of the gas extraction assembly are determined based on the theoretical value information when the theoretical value information is reliable.

[0039] In an embodiment, the step of determining the reliability of the gas extraction assembly based on the theoretical value information comprises:

[0040] A turbulent flow model is established at the gas extraction end of the gas extraction assembly and the gas outlet end of the gas extraction assembly.

[0041] The pressure and flow rate at the gas extraction end of the gas extraction assembly are obtained based on the flow of the centrifugal compressor.

[0042] The back pressure at the gas extraction end of the gas extraction assembly is calculated.

[0043] When the back pressure at the gas extraction end of the gas extraction assembly is greater than the design value of the required gas supply amount of the shaft end sealing chamber, it is determined that the theoretical value information is reliable.

[0044] In an embodiment, the step of determining the parameters of the gas extraction assembly based on the theoretical value information further comprises:

[0045] A vortex model is established through fluid mechanics simulation analysis.

[0046] A first isentropic efficiency, i.e., the isentropic efficiency from the rear stage impeller of the gas extraction assembly to the outlet of the impeller when the gas extraction assembly is not set, is calculated.

[0047] A second isentropic efficiency, i.e., the isentropic efficiency from the rear stage to the outlet of the impeller when the gas extraction assembly is set, is calculated.

[0048] The reliability of the isentropic efficiency is determined based on the comparison result of the first isentropic efficiency and the second isentropic efficiency.

[0049] Compared with the prior art, the present application at least includes the following beneficial effects:

[0050] The compressor provided by the embodiment of the present application comprises a compressor body, a gas taking assembly and a sealing interstage. The compressor body comprises a plurality of impellers which are arranged at the air outlet of the compressor body in a multi-stage series connection mode. The gas taking end of the gas taking assembly is arranged between two adjacent impellers. The gas taking assembly comprises a flow guide pipe. The sealing interstage is arranged at the shaft end of the last-stage impeller of the compressor body. The sealing interstage is in communication with the gas outlet end of the flow guide pipe. In actual use, the process gas of the compressor body is heated and pressurized by the multi-stage impellers. The temperature and pressure of the process gas are too high when the process gas is discharged from the last-stage impeller. If the outlet gas of the last-stage impeller is selected as the sealing gas, the sealing interstage is easily damaged. Therefore, the gas taking assembly is additionally arranged between two adjacent impellers, so that the position of the sealing gas taking is moved forward, and the temperature and pressure of the process gas taken are lower than those of the outlet gas. The technical scheme reduces the temperature and pressure of the sealing gas, improves the safety of the product without using better high-temperature and high-pressure dry gas sealing materials, improves the design level of the sealing gas pipeline pressure, and saves a large amount of cost, thereby prolonging the service life of the product. BRIEF DESCRIPTION OF DRAWINGS

[0051] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments with reference made to the accompanying drawings. The drawings are for purposes of illustration only and are not intended to be limiting in any respect. Like reference numerals have been used in the drawings to describe and refer to like parts throughout the drawings. In the drawings:

[0052] Figure 1 A structural block diagram of the compressor of one embodiment provided by the present application from one perspective;

[0053] Figure 2 A structural block diagram of the compressor of one embodiment provided by the present application from another perspective;

[0054] Figure 3 A structural schematic diagram of the gas flow channel of the compressor of one embodiment provided by the present application;

[0055] Figure 4 A schematic step flow chart of the design method of the compressor of one embodiment provided by the present application;

[0056] Figure 5 A schematic step flow chart of the position information of the gas taking point of the compressor of one embodiment provided by the present application;

[0057] Figure 6A schematic step flow chart of determining that a compressor provided in an embodiment of the present application meets the theoretical value information of the minimum pipe diameter of the gas extraction end of a gas extraction assembly;

[0058] Figure 7 A schematic step flow chart of determining the parameters of the gas extraction assembly of a compressor provided in an embodiment of the present application;

[0059] Figure 8 A schematic step flow chart of determining the parameters of the gas extraction assembly of a compressor provided in another embodiment of the present application.

[0060] wherein, Figures 1-3 The correspondence between the reference signs and the component names in the drawings is as follows:

[0061] 100, compressor body; 200, gas extraction assembly;

[0062] 110, impeller; 120, partition plate; 130, communication pipeline;

[0063] 210, gas extraction pipeline; 220, gas extraction volute; 230, flow guide pipe. DETAILED DESCRIPTION

[0064] In order to better understand the above technical solutions, the technical solutions of the embodiments of the present application will be described in detail below through the drawings and specific embodiments. It should be understood that the specific features in the embodiments of the present application and the embodiments are detailed descriptions of the technical solutions of the embodiments of the present application, and are not limitations of the technical solutions of the present application. In the case of no conflict, the technical features in the embodiments of the present application and the embodiments can be combined with each other.

[0065] As Figures 1-3 shown, according to the first aspect of the present application, a compressor is provided, comprising: a compressor body 100; the compressor body 100 comprises a plurality of impellers 110, and the plurality of impellers 110 are arranged at the air outlet of the compressor body 100 in a multi-stage series manner; a gas extraction assembly 200, the gas extraction end of the gas extraction assembly 200 is arranged between two adjacent impellers 110, the gas extraction assembly 200 comprises a flow guide pipe 230; a sealing interstage, the sealing interstage is arranged at the shaft end of the last stage impeller 110 of the compressor body 100, and the sealing interstage is in communication with the gas outlet end of the flow guide pipe 230.

[0066] The compressor provided by the embodiment of the application comprises a compressor main body 100, a gas taking assembly 200 and a sealing interstage, wherein the compressor main body 100 comprises a plurality of impellers 110, the plurality of impellers 110 are arranged at an air outlet of the compressor main body 100 in a multi-stage series connection mode; a gas taking end of the gas taking assembly 200 is arranged between two adjacent impellers 110, the gas taking assembly 200 comprises a flow guide pipe 230; the sealing interstage is arranged at a shaft end of the last-stage impeller 110 of the compressor main body 100, and the sealing interstage is in communication with an air outlet end of the flow guide pipe 230; in actual use, process gas of the compressor main body 100 is heated and pressurized through the multi-stage impellers 110, the temperature and the air pressure of the process gas are too high when the process gas is discharged from the last-stage impeller 110, and if the outlet gas of the last-stage impeller 110 is selected as the sealing gas, the sealing interstage is easily damaged, therefore, the gas taking assembly 200 is additionally arranged between two adjacent impellers 110, the position of the sealing gas is moved forward, the temperature and the air pressure of the process gas used are lower than those of the outlet gas, the temperature and the pressure of the sealing gas are reduced, the sealing gas pipeline pressure design pound level is improved without using better high-temperature and high-pressure dry gas sealing materials, the safety of the product is improved, and the service life of the product is prolonged.

[0067] As shown in Figures 1-3 , the compressor main body 100 further comprises a centrifugal compressor casing, and a partition plate 120 arranged between every two adjacent impellers 110.

[0068] In the technical scheme, the partition plate 120 is additionally arranged between every two impellers 110, the partition plate 120 can provide a mounting fulcrum for the frame of the impeller 110, improve the integrity and stability of the compressor main body 100, and provide a mounting base for various components and lead wires between the two adjacent impellers 110, limit the displacement direction of the outlet gas, and reduce the outlet cross-sectional area of the outlet gas, so as to facilitate the pressure increase of the process gas by the lower-stage impeller 110.

[0069] As shown in Figures 1-3 , the compressor main body 100 further comprises a communication pipeline 130 and a diffuser, the communication pipeline 130 is a bend pipe, and the communication pipeline 130 is arranged between every two adjacent impellers 110 and used for connecting the two adjacent impellers 110; the diffuser is arranged in the communication pipeline 130.

[0070] In the technical scheme, the compressor main body 100 further comprises the communication pipeline 130 and the diffuser, the communication pipeline 130 is arranged between every two impellers 110 and used for connecting the two impellers 110 to transport the process gas, and the diffuser is arranged in the communication pipeline 130 to increase the pressure, and further improve the compression efficiency of the compressor main body 100 on the process gas.

[0071] As shown in Figures 1-3 The gas taking assembly 200 includes a gas taking pipeline 210, a gas taking port of the gas taking pipeline 210 is arranged along a tangent direction of the communication pipeline 130, and the gas taking pipeline 210 is communicated with the flow guide pipe 230.

[0072] In the technical solution, the gas taking assembly 200 includes the gas taking pipeline 210, the gas taking port of the gas taking pipeline 210 is arranged along the tangent direction of the communication pipeline 130, the gas taking pipeline 210 is communicated with the flow guide pipe 230, and the gas taking pipeline 210 is arranged along the tangent direction of the communication pipeline 130, so that the process gas entering the gas taking pipeline 210 is maximized without adding a redundant component such as a gas valve, and the gas amount of the sealing interstage seal gas is ensured.

[0073] As shown in Figures 1-3 The gas taking assembly 200 further includes a gas taking volute chamber 220, the gas taking volute chamber 220 is arranged between the gas taking pipeline 210 and the flow guide pipe 230, and the gas taking volute chamber 220 is arranged inside the partition plate 120.

[0074] In the technical solution, the gas taking assembly 200 further includes the gas taking volute chamber 220, the process gas entering the gas taking pipeline 210 causes vibration, which affects the stability of the compressor main body 100, so the gas taking volute chamber 220 is added, the gas taking volute chamber 220 is arranged inside the partition plate 120 and between the gas taking pipeline 210 and the flow guide pipe 230, and the gas taking volute chamber 220 gradually increases the outer diameter and gradually expands the flow passage section during the process of collecting the gas, so as to slow down the gas flow and reduce the vibration effect on the compressor main body 100.

[0075] As shown in Figure 4 According to a second aspect of the embodiments of the present application, a design method of a compressor is provided, which is used for designing the compressor as described in any one of the above embodiments, and the design method of the compressor includes:

[0076] Step 100: confirming position information of a gas taking point;

[0077] Step 200: determining theoretical value information of a minimum pipe diameter of a gas taking end of a gas taking assembly based on the position information;

[0078] Step 300: determining parameters of the gas taking assembly based on the theoretical value information.

[0079] In the technical scheme, the design method of the compressor is provided, after the position information of the gas taking point and the minimum theoretical value of the gas taking pipe diameter are set, the gas taking point needs to be verified to ensure the feasibility, the main aspects of the verification include whether the gas temperature and pressure of the gas taking point process gas are lower than the design pressure of the sealing stage, whether the gas taking amount of the gas taking point process gas can meet the requirements of the sealing stage, and the like, after the verification meets the requirements, the position information of the gas taking point is determined, and the design of the compressor is completed.

[0080] As shown in Figure 5 the step of confirming the position information of the gas taking point comprises:

[0081] Step 110: selecting a preselected gas taking point between any two impellers;

[0082] Step 120: obtaining the process gas temperature and pressure information of all the preselected gas taking points according to the flow of the centrifugal compressor;

[0083] Step 130: taking the preselected gas taking point with the process gas temperature and pressure information lower than the tolerance temperature and pressure of the shaft end sealing material as the gas taking point.

[0084] In the technical scheme, the preselected gas taking point is selected between any two impellers, because the number of impeller stages is limited, the number of the preselected gas taking points is limited, and the number is usually less than ten, the preselected and then verified method is more convenient for calculation, after the preselected gas taking point is determined, the process gas temperature and pressure information of the preselected gas taking point is obtained according to the flow of the centrifugal compressor, and when the process gas temperature and pressure are lower than the tolerance temperature and pressure of the shaft end sealing material, the preselected gas taking point can be taken as the gas taking point.

[0085] As shown in Figure 6 the step of determining the theoretical value information of the minimum pipe diameter of the gas taking end of the gas taking assembly based on the position information comprises:

[0086] Step 210: establishing a turbulent flow model for the gas taking assembly inlet and the flow guide pipe outlet;

[0087] Step 220: obtaining the pressure and flow rate of the gas taking assembly inlet through the flow of the centrifugal compressor;

[0088] Step 230: determining the theoretical value information of the minimum pipe diameter of the gas taking end of the gas taking assembly based on the pressure and flow rate of the gas taking assembly inlet and the design value of the required gas amount of the shaft end sealing chamber.

[0089] In the technical solution, the minimum pipe diameter of the gas taking end of the gas taking assembly is verified. In the embodiment of the application, the gas inlet end of the gas taking assembly is the gas taking pipeline. Since the gas taking pipeline is arranged in the compressor main body, the space is limited, and when the pipe diameter of the gas taking pipeline is too large, the outlet gas pressure and the gas quantity are easily affected. Therefore, the minimum value of the gas taking end pipe diameter needs to be calculated and verified. In the verification, a turbulent flow model is established for the gas taking assembly gas inlet end and the flow guide pipe gas outlet end. The pressure and flow rate of the gas taking assembly gas inlet end are obtained through the flow of the centrifugal compressor, that is, the process gas pressure and flow rate between the front-stage impeller and the rear-stage impeller of the selected gas taking point. The minimum value of the gas taking assembly gas inlet end is calculated according to the design value of the required gas quantity of the shaft end sealing chamber. In general, for the convenience of subsequent calculation and production, the design value of the gas taking assembly gas inlet end is the next integral of the minimum value.

[0090] As shown in Figure 7 , the step of determining the parameters of the gas taking assembly based on the theoretical value information includes:

[0091] determining the reliability of the gas taking assembly based on the theoretical value information, and determining the parameters of the gas taking assembly based on the theoretical value information when the theoretical value information is reliable;

[0092] The step of determining the reliability of the gas taking assembly based on the theoretical value information includes:

[0093] Step 311: establishing a turbulent flow model for the gas taking assembly inlet end and the gas taking assembly outlet end;

[0094] Step 312: obtaining the pressure and flow rate of the flow guide pipe gas inlet end based on the flow of the centrifugal compressor;

[0095] Step 313: calculating the back pressure of the gas taking assembly outlet end;

[0096] Step 314: when the back pressure of the gas taking assembly outlet end is greater than the design value of the required gas quantity of the shaft end sealing chamber, it is determined that the theoretical value information is reliable.

[0097] In the technical solution, a turbulent flow model is established for the gas taking assembly inlet end and the gas taking assembly outlet end. The back pressure of the gas taking assembly outlet end can be calculated based on the design value of the gas taking assembly gas inlet and the pressure and flow rate of the gas taking assembly gas inlet end. When the back pressure of the gas taking assembly outlet end is greater than the design value of the required gas quantity of the shaft end sealing chamber, it is determined that the theoretical value information is reliable. If the calculated value is less than the design value, the preselected gas taking point or the pipe diameter of the gas taking assembly inlet end is considered to be replaced.

[0098] As shown in Figure 8 , based on the theoretical value information, the parameters of the gas taking assembly are determined, which further includes:

[0099] Step 321: establishing a vortex model through fluid mechanics simulation analysis;

[0100] Step 322: calculate the first isentropic efficiency, i.e. the isentropic efficiency of the stage behind the extraction assembly to the impeller outlet when the extraction assembly is not set;

[0101] Step 323: calculate the second isentropic efficiency, i.e. the isentropic efficiency of the stage behind the extraction assembly to the impeller outlet when the extraction assembly is set;

[0102] Based on the comparison result of the first isentropic efficiency and the second isentropic efficiency, the reliability of the isentropic efficiency is determined.

[0103] In the technical scheme, the isentropic efficiency of the stage behind the extraction assembly to the impeller outlet when the extraction assembly is not set is calculated as the first isentropic efficiency, the isentropic efficiency of the stage behind the extraction assembly to the impeller outlet when the extraction assembly is set is calculated as the second isentropic efficiency, the first isentropic efficiency and the second isentropic efficiency are compared, the influence of the installed extraction assembly on the outlet gas of the centrifugal compressor is obtained, and whether the influence of the extraction assembly on the isentropic efficiency of the outlet gas is acceptable is determined according to the production and use requirements, if not acceptable, the extraction point is considered to be replaced, the pipe diameter design value of the extraction assembly is reduced, and adjustment is performed, and finally the selection of the extraction point of the compressor is completed.

[0104] In the present application, the terms "first", "second", "third" are only used for the purpose of description, and cannot be understood as indicating or implying relative importance; the term "multiple" refers to two or more, unless otherwise explicitly limited. The terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, "connection" can be fixed connection, or detachable connection, or integral connection; "connection" can be direct connection, or indirect connection through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0105] In the description of the present application, it should be understood that the terms "upper", "lower", "left", "right", "front", "back" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the devices or units referred to must have a particular direction, be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the present application.

[0106] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "certain embodiments", and the like is intended to indicate that the described implementation, feature, structure, material or characteristic is included in at least one embodiment or example of the application. The illustrative representations of the above terms in the specification are not necessarily referring to the same embodiment or example. Moreover, the described implementation, feature, structure, material or characteristic can be combined in any one or more embodiments or examples in a suitable manner.

[0107] The above only is the preferred embodiment of the present application, and is not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A compressor characterized by, Comprise: A compressor body; The compressor body comprises a plurality of impellers, a plurality of the impellers are arranged in a multi-stage series at the air outlet of the compressor body; A gas taking assembly, the gas taking end of the gas taking assembly is arranged between two adjacent stages of impellers, the gas taking assembly comprises a flow guide pipe, a gas taking pipeline and a gas taking volute; The gas taking port of the gas taking pipeline is arranged along the tangent direction of the communication pipeline, and is communicated with the flow guide pipe; A gas taking volute, the gas taking volute is arranged between the gas taking pipeline and the flow guide pipe, and the gas taking volute is arranged inside the partition plate; A sealing interstage, the sealing interstage is arranged at the shaft end of the last stage of impellers of the compressor body, and the sealing interstage is communicated with the air outlet end of the flow guide pipe.

2. The compressor of claim 1, wherein, The compressor body further comprises: A centrifugal compressor casing; A partition plate, the partition plate is arranged between every two adjacent stages of impellers.

3. The compressor of claim 2, wherein, The compressor body further comprises: A communication pipeline, the communication pipeline is a bend pipe, the communication pipeline is arranged between every two adjacent stages of impellers, and is used for communicating the two adjacent stages of impellers; An expander, the expander is arranged in the communication pipeline.

4. A method of designing a compressor, characterized by, A design method for designing the compressor as claimed in any one of claims 1-3, the design method of the compressor comprises: Confirming position information of a gas taking point; Based on the position information, determining theoretical value information of satisfying a minimum pipe diameter of a gas taking end of a gas taking assembly; Based on the theoretical value information, determining parameters of the gas taking assembly.

5. A method of designing a compressor according to claim 4, wherein The step of confirming the position information of the gas taking point comprises: Selecting a preselected gas taking point between any two stages of impellers; According to the flow of the centrifugal compressor, obtaining process gas temperature and pressure information of all preselected gas taking points; Taking the preselected gas taking point with the process gas temperature and pressure information lower than the tolerance temperature and pressure of the shaft end sealing material as the gas taking point.

6. A method of designing a compressor according to claim 4, wherein The step of determining the theoretical value information of satisfying the minimum pipe diameter of the gas taking end of the gas taking assembly based on the position information comprises: Establishing a turbulent flow model with the gas taking end of the gas taking assembly and the air outlet end of the flow guide pipe; Obtaining the pressure and flow rate of the gas taking end of the gas taking assembly through the flow of the centrifugal compressor; Based on the pressure and flow rate of the gas taking end of the gas taking assembly and the design value of the required gas supply amount of the shaft end sealing chamber, determining the theoretical value information of the minimum pipe diameter of the gas taking end of the gas taking assembly.

7. The method of designing a compressor according to claim 4, wherein The step of determining the parameters of the gas taking assembly based on the theoretical value information comprises: Determining the reliability of the gas taking assembly based on the theoretical value information, and determining the parameters of the gas taking assembly based on the theoretical value information in the case that the theoretical value information is reliable; The step of determining the reliability of the gas taking assembly based on the theoretical value information comprises: Establishing a turbulent flow model with the gas taking end of the gas taking assembly and the gas taking end of the gas taking assembly; Based on the flow of the centrifugal compressor, obtaining the pressure and flow rate of the gas taking end of the flow guide pipe; Calculating the back pressure of the gas taking end of the gas taking assembly; When the back pressure of the gas taking end of the gas taking assembly is greater than the design value of the required gas supply amount of the shaft end sealing chamber, it is determined that the theoretical value information is reliable.

8. The method of designing a compressor according to claim 4, wherein Based on the theoretical value information, determining the parameters of the gas taking assembly further comprises: Establishing a vortex model through fluid mechanics simulation analysis; Calculating the first isentropic efficiency, that is, the isentropic efficiency from the impeller to the outlet of the impeller of the rear stage of impellers of the gas taking assembly without the gas taking assembly; Calculate the second isentropic efficiency, that is, the isentropic efficiency from the rear stage of the extraction assembly to the outlet of the impeller when the extraction assembly is set; Determine the reliability of the entropy efficiency based on the comparison result of the first isentropic efficiency and the second isentropic efficiency.

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