Wheel cover self-pressurizing sealing structure of closed centrifugal impeller and closed centrifugal impeller

Abstract

The present application relates to the sealing technical field of closed centrifugal impeller, in particular to a wheel cover self-boosting sealing structure of closed centrifugal impeller and the closed centrifugal impeller. The wheel cover self-boosting sealing structure comprises: a channel component for generating a high-pressure gas film in the gap between the wheel cover of the centrifugal impeller and the casing of the centrifugal impeller; the channel component is provided with a boosting channel and a high-pressure gas film channel; the high-pressure gas film channel is an annular groove arranged in the circumferential direction of the channel component; the boosting channel is in communication with the high-pressure gas film channel, and the flow area of the boosting channel gradually decreases towards the high-pressure gas film channel; when the closed centrifugal impeller rotates, part of the airflow at the inlet of the closed centrifugal impeller enters the channel component to be boosted, and a high-pressure gas film for plugging the leakage gap is generated in the high-pressure gas film channel. Through the above structure, the problem that the closed centrifugal impeller in the prior art is difficult to effectively reduce leakage due to the restriction of the machining precision and assembly precision of the device can be effectively overcome.

Description

Technical Field

[0001] This invention relates to the field of sealing technology for closed centrifugal impellers, specifically to a self-pressurizing sealing structure for the impeller cover of a closed centrifugal impeller and a closed centrifugal impeller. Background Technology

[0002] Energy storage is a key supporting technology for the energy revolution, effectively improving the utilization rate of renewable energy and ensuring the efficiency, security, and economy of regional energy systems. Advanced compressed air energy storage (CASS) technology, as one of the large-scale physical energy storage technologies, boasts large storage capacity, long cycle time, and broad development prospects. Centrifugal compressors are one of the key devices in advanced CASS energy storage. Through the compression process, they convert excess electrical energy into air internal energy and pressure potential energy, storing it. When needed, the compressed air is released to drive a turbine expander to generate electricity, achieving efficient conversion, storage, and utilization of electrical energy. The compressors in advanced CASS energy storage systems are characterized by medium flow rate, high exhaust pressure, and a wide range of variable operating conditions. The compression process is highly coupled with heat storage and heat exchange, and surge phenomena objectively exist. To achieve high exhaust pressure, multi-stage compressors are typically used in CASS energy storage systems for sequential compression. Given that tip leakage in semi-open impellers severely affects the compressor pressure ratio and system efficiency, the high-pressure stage of the compressor in a CASS energy storage system typically uses a closed centrifugal impeller. This impeller structure effectively suppresses tip clearance leakage, optimizes the flow structure at the top of the blade channel, and improves the impeller pressure ratio and system efficiency.

[0003] A closed impeller consists of a disc, blades, and a cover. When the compressor is working normally, the impeller rotates at high speed with the main shaft. Under the action of the impeller blades, the gas also rotates at high speed with the impeller. Due to the centrifugal force of rotation and the diffusion flow inside the impeller channel, the gas pressure, velocity, and temperature are all effectively increased at the impeller outlet.

[0004] Structurally, the closed impeller rotates at high speed with the main shaft, while the casing remains stationary. This results in a dynamic and static mating surface between the closed impeller cover and the casing, inevitably creating a gap that forms a flow channel. This is described in existing technology... Figure 3 and Figure 4 As shown, the gas pressure at the impeller outlet is high, while the impeller inlet is in a low-pressure state due to suction. Under the pressure difference between the inlet and outlet of a closed impeller, the high-pressure gas at the impeller outlet, after passing through the aforementioned... Figure 4 The leakage flow between the impeller cover 101 and the casing 102 causes backflow to the impeller inlet, forming a leakage flow and resulting in leakage losses, which in turn leads to a decrease in compressor efficiency. At the same time, this leakage flow at the impeller inlet also affects the impeller inlet parameters, causing the internal flow of the impeller to deteriorate, further reducing the compressor efficiency.

[0005] Currently, the main methods for reducing leakage between the impeller cover 101 and the casing 102 in existing technologies are reducing the gap size or using a grate-type sealing structure. Both of these methods reduce leakage by increasing flow resistance. However, these two methods are limited by the processing and assembly precision of the device, making it difficult to effectively reduce leakage and increasing the production and processing costs of closed centrifugal impellers. Summary of the Invention

[0006] Therefore, the technical problem to be solved by the present invention is to overcome the problem that the closed centrifugal impeller in the prior art is difficult to effectively reduce leakage due to the limitations of the processing accuracy and assembly accuracy of the device. To this end, the present invention provides a self-pressurizing sealing structure for the impeller cover of a closed centrifugal impeller, the closed centrifugal impeller comprising: a centrifugal impeller cover, a disc disposed on the centrifugal impeller cover, and blades disposed between the centrifugal impeller cover and the disc;

[0007] A leakage gap exists between the centrifugal impeller cover and the centrifugal impeller casing. When the closed centrifugal impeller rotates, the working fluid leaks from the impeller outlet to the impeller inlet through the leakage gap.

[0008] The wheel cover self-pressurizing sealing structure includes:

[0009] The channel component is a columnar structure disposed on the side of the centrifugal impeller cover away from the impeller disk. The channel component is used to generate a high-pressure gas film in the gap between the centrifugal impeller cover and the centrifugal impeller casing. The channel component is provided with a pressurization channel and a high-pressure gas film channel.

[0010] The high-pressure air film channel is an annular groove provided in the circumferential direction of the channel component, and the high-pressure air film channel is provided on the side of the channel component near the centrifugal impeller cover; the pressurizing channel is connected to the high-pressure air film channel, and the flow area of ​​the pressurizing channel gradually decreases towards the high-pressure air film channel.

[0011] When the closed centrifugal impeller rotates, part of the airflow at the inlet of the closed centrifugal impeller enters the channel component for pressurization, and a high-pressure gas film is generated in the high-pressure gas film channel to seal the leakage gap.

[0012] Optionally, the working medium is a gaseous working medium, and the high-pressure gas film generated in the high-pressure gas film channel has the same pressure as the leakage flow in the leakage gap, so as to suppress the leakage of the gaseous working medium from the impeller outlet to the impeller inlet through the leakage gap.

[0013] Optionally, the channel component and the centrifugal impeller cover are an integral structure.

[0014] Optionally, the channel component is detachably fixed to the centrifugal impeller cover.

[0015] Optionally, the pressurization channel and / or the high-pressure film channel are channels with a wedge-shaped cross-section; and / or,

[0016] The pressurization channel and / or the high-pressure air film channel are channels with a circular arc cross-section.

[0017] Optionally, the channel component is made of the same material as the closed centrifugal impeller; the channel component is made of titanium alloy or 520B stainless steel.

[0018] Optionally, the working medium is air, nitrogen, oxygen, fuel gas, or carbon dioxide.

[0019] A closed-type centrifugal impeller includes: a self-pressurizing sealing structure for the impeller cover; and,

[0020] Centrifugal impeller cover, a disc disposed on the centrifugal impeller cover, and blades disposed between the centrifugal impeller cover and the disc.

[0021] Optionally, closed-loop centrifugal impellers are used in: compressed air energy storage, renewable energy power generation devices, aircraft engine compressors, and chemical process compressors.

[0022] The technical solution of this invention has the following advantages:

[0023] 1. The closed-type centrifugal impeller with a self-pressurizing sealing structure for the impeller cover provided by the present invention includes:

[0024] The channel component is a columnar structure disposed on the side of the centrifugal impeller cover away from the impeller disk. The channel component is used to generate a high-pressure gas film in the gap between the centrifugal impeller cover and the centrifugal impeller casing. The channel component is provided with a pressurization channel and a high-pressure gas film channel.

[0025] The high-pressure air film channel is an annular groove provided in the circumferential direction of the channel component, and the high-pressure air film channel is provided on the side of the channel component near the centrifugal impeller cover; the pressurization channel is connected to the high-pressure air film channel, and the flow area of ​​the pressurization channel gradually decreases towards the high-pressure air film channel.

[0026] When the closed centrifugal impeller rotates, part of the airflow at the inlet of the closed centrifugal impeller enters the channel component for pressurization, and a high-pressure gas film is generated in the high-pressure gas film channel to seal the leakage gap.

[0027] In this invention, the aforementioned channel component effectively suppresses leakage of the working gas from the impeller outlet through the gap between the centrifugal impeller cover and the centrifugal impeller casing to the impeller inlet. This solves the problem of large flow losses caused by leakage flow between the centrifugal impeller cover and the centrifugal impeller casing during the operation of a closed impeller, meeting the requirements for high-efficiency operation of the closed centrifugal impeller, further increasing the aerodynamic efficiency of the closed impeller, promoting the efficient operation of the closed impeller in energy systems, and possessing advantages such as convenient processing, low cost, and easy assembly. Specifically, a channel component is provided at the gap between the centrifugal impeller cover and the centrifugal impeller casing, and located around the inlet of the centrifugal impeller cover in a closed structure, arranged circumferentially around the cover. The opening direction of the aforementioned channel component is related to the rotation direction of the closed centrifugal impeller. When the closed-loop centrifugal impeller rotates, the airflow at the inlet of the impeller enters the channel component and is pressurized, generating a high-pressure gas film within the high-pressure gas film channel to seal the leakage gap. This high-pressure gas film effectively suppresses the leakage of the working gas from the impeller outlet through the gap between the impeller cover and the casing to the impeller inlet. Furthermore, during normal operation of the closed-loop centrifugal impeller in this invention, the high-pressure gas film generated at the gap between the impeller cover and the impeller casing is a non-contact seal, which not only has a simple and reliable manufacturing process but also a long service life.

[0028] 2. The self-pressurizing sealing structure of the impeller cover of the closed centrifugal impeller provided by the present invention, wherein the working medium is a gaseous working medium, and the high-pressure gas film generated in the high-pressure gas film channel has the same pressure as the leakage flow in the leakage gap, so as to suppress the leakage of the gaseous working medium from the impeller outlet to the impeller inlet through the leakage gap.

[0029] In this invention, by adjusting the specific dimensions of the channel components, the high-pressure gas film generated in the high-pressure gas film channel can be made to have the same pressure as the leakage flow pressure in the leakage gap, thereby completely suppressing the leakage of the gas working fluid through the aforementioned leakage gap.

[0030] 3. The self-pressurizing sealing structure of the closed centrifugal impeller cover provided by the present invention, wherein the channel component and the centrifugal impeller cover are an integral structure; and / or, the channel component is detachably fixed on the centrifugal impeller cover.

[0031] In this invention, designing the channel component to be detachably fixed to the centrifugal impeller cover allows workers to replace the channel component as needed, facilitating replacement after wear. Furthermore, the integrated structure of the channel component and the centrifugal impeller cover offers the advantage of robust and reliable construction.

[0032] 4. The closed centrifugal impeller provided by the present invention includes: a channel component; and a centrifugal impeller cover, a disc disposed on the centrifugal impeller cover, and blades disposed between the centrifugal impeller cover and the disc.

[0033] The closed centrifugal impeller in this invention includes a channel component, thus possessing all the advantages of a self-pressurizing sealing structure with a wheel cover. Attached Figure Description

[0034] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0035] Figure 1 This is a side view of the internal structure of the closed centrifugal impeller in this invention;

[0036] Figure 2 This is a partially enlarged schematic diagram of the internal structure of the closed centrifugal impeller in this invention;

[0037] Figure 3 This is a side view of the internal structure of a closed centrifugal impeller in the prior art.

[0038] Figure 4 This is a schematic diagram of the leakage flow direction of a closed centrifugal impeller outlet leaking to the impeller inlet through a leakage gap in the prior art.

[0039] Explanation of reference numerals in the attached figures:

[0040] 1 - Centrifugal impeller cover; 2 - Impeller disc; 3 - Blade; 4 - Leakage gap; 5 - Centrifugal impeller casing; 6 - Channel component; 7 - Pressurization channel; 8 - High-pressure gas film channel; 101 - Impeller cover; 102 - Casing. Detailed Implementation

[0041] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0043] Example 1

[0044] This embodiment provides a self-pressurizing sealing structure for the impeller cover of a closed centrifugal impeller, such as... Figure 1 As shown, the closed centrifugal impeller includes: a centrifugal impeller cover 1, a disc 2 disposed on the centrifugal impeller cover 1, and blades 3 disposed between the centrifugal impeller cover 1 and the disc 2; there is a leakage gap 4 between the centrifugal impeller cover 1 and the centrifugal impeller casing 5, and when the closed centrifugal impeller rotates, the gaseous working medium leaks from the impeller outlet to the impeller inlet through the leakage gap 4.

[0045] like Figure 1 and Figure 2 The self-pressurizing sealing structure of the wheel cover shown includes:

[0046] The channel component 6 is a columnar structure disposed on the side of the centrifugal impeller cover 1 away from the impeller disk 2. The channel component 6 is used to generate a high-pressure gas film within the gap between the centrifugal impeller cover 1 and the centrifugal impeller housing 5. The channel component 6 is provided with a pressurization channel 7 and a high-pressure gas film channel 8. The pressurization channel 7 and the high-pressure gas film channel 8 are channels with a wedge-shaped cross-section. In addition, in this embodiment, the channel component 6 is detachably fixed to the centrifugal impeller cover 1 by fasteners. In this embodiment, the channel component 6 is made of the same material as the closed centrifugal impeller, which is titanium alloy.

[0047] The aforementioned high-pressure gas film channel 8 is an annular groove disposed in the circumferential direction of the channel component 6, and the high-pressure gas film channel 8 is disposed on the side of the channel component 6 near the centrifugal impeller cover 1; the pressurizing channel 7 is connected to the high-pressure gas film channel 8, and the flow area of ​​the pressurizing channel 7 gradually decreases towards the high-pressure gas film channel 8; when the closed centrifugal impeller rotates, part of the airflow at the inlet of the closed centrifugal impeller enters the channel component 6 for pressurization, and a high-pressure gas film for sealing the leakage gap 4 is generated in the high-pressure gas film channel 8. In this invention, the airflow enters the channel component 6 for pressurization, and a high-pressure gas film for sealing the leakage gap 4 is generated in the high-pressure gas film channel 8. The aforementioned high-pressure gas film can effectively suppress the leakage of the working gas from the impeller outlet through the gap between the cover and the casing to the impeller inlet. Moreover, the high-pressure gas film in this invention seals the leakage gap 4 in a non-contact manner. This method not only has the advantages of simple and reliable manufacturing process, but also has the advantages of long service life.

[0048] In this invention, in order to completely suppress the leakage of the working gas through the aforementioned leakage gap 4, the high-pressure gas film generated in the high-pressure gas film channel 8 has the same pressure as the leakage flow in the leakage gap 4, thereby effectively suppressing the leakage of the working gas from the impeller outlet to the impeller inlet through the leakage gap 4.

[0049] Of course, this embodiment does not specifically limit the type of gaseous working medium. In other embodiments, the gaseous working medium is air, nitrogen, oxygen, fuel gas, or carbon dioxide.

[0050] Of course, this embodiment does not specifically limit the connection method between the channel component 6 and the centrifugal impeller cover 1. In other embodiments, the channel component 6 and the centrifugal impeller cover 1 can also be an integral structure.

[0051] Of course, this embodiment does not specifically limit the cross-sectional shape of the pressurization channel 7 and the high-pressure air film channel 8. In other embodiments, the pressurization channel 7 and the high-pressure air film channel 8 are channels with a circular arc cross-section.

[0052] Of course, this embodiment does not specifically limit the high-pressure gas film pressure value generated in the high-pressure gas film channel 8. In other embodiments, the high-pressure gas film pressure generated in the high-pressure gas film channel 8 may be less than or greater than the leakage flow pressure in the leakage gap 4.

[0053] Of course, this embodiment does not specifically limit whether the channel component 6 and the closed centrifugal impeller are made of the same material. In other embodiments, the channel component 6 and the closed centrifugal impeller are made of different materials.

[0054] Of course, this embodiment does not specifically limit the material of the channel component 6 and the closed centrifugal impeller. In other embodiments, the material of the channel component 6 and the closed centrifugal impeller is 520B stainless steel.

[0055] Example 2

[0056] A closed centrifugal impeller, such as Figure 3 As shown, it includes: a channel component 6; and a centrifugal impeller cover 1, a disc 2 disposed on the centrifugal impeller cover 1, and blades 3 disposed between the centrifugal impeller cover 1 and the disc 2. Furthermore, the aforementioned closed centrifugal impeller is used in: compressed air energy storage, renewable energy power generation devices, aircraft engine compressors, and chemical process compressors.

[0057] The wheel cover self-pressurizing sealing structure includes:

[0058] The channel component 6 is a columnar structure disposed on the side of the centrifugal impeller cover 1 away from the impeller 2. The channel component 6 is used to generate a high-pressure gas film in the gap between the centrifugal impeller cover 1 and the centrifugal impeller casing 5. The channel component 6 is provided with a pressurization channel 7 and a high-pressure gas film channel 8.

[0059] The aforementioned high-pressure gas film channel 8 is an annular groove provided in the circumferential direction of the channel component 6, and the high-pressure gas film channel 8 is provided on the side of the channel component 6 near the centrifugal impeller cover 1; the pressurization channel 7 is connected to the high-pressure gas film channel 8, and the flow area of ​​the pressurization channel 7 gradually decreases towards the high-pressure gas film channel 8; when the closed centrifugal impeller rotates, part of the airflow at the inlet of the closed centrifugal impeller enters the channel component 6 for pressurization, and generates a high-pressure gas film in the high-pressure gas film channel 8 to seal the leakage gap 4.

[0060] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A self-pressurizing sealing structure for the impeller cover of a closed centrifugal impeller, the closed centrifugal impeller comprising: Centrifugal impeller cover (1), a wheel disc (2) disposed on the centrifugal impeller cover (1), and blades (3) disposed between the centrifugal impeller cover (1) and the wheel disc (2); There is a leakage gap (4) between the centrifugal impeller cover (1) and the centrifugal impeller casing (5). When the closed centrifugal impeller rotates, the working fluid leaks from the impeller outlet to the impeller inlet through the leakage gap (4). The wheel cover self-pressurizing sealing structure is characterized by: The channel component (6) is a columnar structure disposed on the side of the centrifugal impeller cover (1) away from the impeller disk (2). The channel component (6) is used to generate a high-pressure gas film in the gap between the centrifugal impeller cover (1) and the centrifugal impeller casing (5). The channel component (6) is provided with a pressurization channel (7) and a high-pressure gas film channel (8). The high-pressure gas film channel (8) is an annular groove provided in the circumferential direction of the channel component (6), and the high-pressure gas film channel (8) is provided on the side of the channel component (6) near the centrifugal impeller cover (1); the pressurizing channel (7) is connected to the high-pressure gas film channel (8), and the flow area of ​​the pressurizing channel (7) gradually decreases towards the high-pressure gas film channel (8); When the closed centrifugal impeller rotates, part of the airflow at the inlet of the closed centrifugal impeller enters the channel component (6) for pressurization, and generates a high-pressure gas film in the high-pressure gas film channel (8) to seal the leakage gap (4).

2. The self-pressurizing sealing structure of the impeller cover of the closed centrifugal impeller according to claim 1, characterized in that, The working medium is a gaseous working medium. The high-pressure gas film generated in the high-pressure gas film channel (8) has the same leakage flow pressure as the leakage gap (4) to suppress the gaseous working medium from the impeller outlet to the impeller inlet through the leakage gap (4).

3. The self-pressurizing sealing structure of the impeller cover of the closed centrifugal impeller according to claim 1 or 2, characterized in that, The channel component (6) and the centrifugal impeller cover (1) are an integral structure.

4. The self-pressurizing sealing structure of the impeller cover of the closed centrifugal impeller according to claim 1 or 2, characterized in that, The channel component (6) is detachably fixed to the centrifugal impeller cover (1).

5. The self-pressurizing sealing structure of the impeller cover of the closed centrifugal impeller according to claim 1 or 2, characterized in that, The pressurization channel (7) and / or the high-pressure air film channel (8) are channels with a wedge-shaped cross-section; and / or, The pressurization channel (7) and / or the high-pressure air film channel (8) are channels with a circular arc cross-section.

6. The self-pressurizing sealing structure of the impeller cover of the closed centrifugal impeller according to claim 1 or 2, characterized in that, The channel component (6) is made of the same material as the closed centrifugal impeller; the channel component (6) is made of titanium alloy or 520B stainless steel.

7. The self-pressurizing sealing structure of the impeller cover of the closed centrifugal impeller according to claim 2, characterized in that, The working medium is air, nitrogen, oxygen, fuel gas, or carbon dioxide.

8. A closed-type centrifugal impeller, characterized in that, include: The wheel cover self-pressurizing sealing structure according to any one of claims 1 to 6; as well as, Centrifugal impeller cover (1), a wheel disc (2) disposed on the centrifugal impeller cover (1), and blades (3) disposed between the centrifugal impeller cover (1) and the wheel disc (2).

9. The closed centrifugal impeller according to claim 8, characterized in that, Closed-type centrifugal impellers are used in: compressed air energy storage, renewable energy power generation devices, aircraft engine compressors, and chemical process compressors.

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