A magnetic fluid seal rim impeller structure for inhibiting tip clearance leakage

Abstract

The application discloses a kind of magnetic fluid sealing rim impeller structures for inhibiting blade tip clearance leakage, including pump shell, be provided with blade in pump shell, a circle of blade cover plate is equipped in the periphery of blade, blade cover plate and pump shell have sealing gap in radial direction, one or more magnetic fluid sealing rings are arranged in sealing gap along the axial direction;Magnetic force structure is arranged in the outer wall of pump shell in annular, magnetic concentration structure is arranged in the inner wall of pump shell in annular, closed magnetic circuit is formed between magnetic concentration structure and magnetic force structure, so that gradient magnetic field is formed at sealing gap;Magnetic fluid is adsorbed and positioned in the corresponding area of sealing gap under the action of gradient magnetic field, and forms a magnetic fluid sealing ring which is consistent with the shape of sealing gap, continuous and stable.The application utilizes the self-positioning characteristics of magnetic fluid under magnetic field, forms dynamic, self-adapting sealing interface between blade cover plate and pump shell, realizes zero leakage operation, improves the hydraulic efficiency and stability of axial flow pump unit.

Description

TECHNICAL FIELD

[0001] The present application relates to a multiphase mixed delivery pump, in particular to a magnetic fluid sealing rim impeller structure for suppressing tip clearance leakage. BACKGROUND

[0002] The key to deep-sea oil and gas resource development lies in the spiral-axial multiphase mixed delivery pump, which can directly pump the unseparated oil-gas-water mixture. The most critical problem in the design and operation of the spiral-axial multiphase mixed delivery pump is the flow instability problem induced by the tip clearance in the pump.

[0003] The leakage flow induced by the tip clearance is a typical and complex flow phenomenon. Especially when the conveying medium contains sand, fine particles or other abrasive components, the tip clearance area is more prone to particle intrusion and deposition, which exacerbates the erosion and wear of the blade rim and the pump shell wall, leading to the gradual expansion of the gap size and the further enhancement of the leakage flow, forming a positive feedback performance degradation cycle.

[0004] Although previous studies have attempted to reduce leakage and wear by improving blade profiles, optimizing gap sizes, or using wear-resistant coatings, these methods are passive defenses and cannot fundamentally achieve long-term, self-adaptive, and zero-leakage sealing effects. On the other hand, some advanced sealing technologies have been successfully applied in other fields, but their inherent technical characteristics make it difficult to directly transfer them to this technical field.

[0005] The magnetic fluid sealing technology represented by the utility patent (CN203463257U) has achieved excellent sealing of gas in rotary shaft sealing such as vacuum pumps, but its application scenario is clean and one-way shaft sealing. When applied to the tip clearance sealing of a multiphase pump, it has fundamental deficiencies and cannot effectively adapt to the large annular gap sealing between the impeller rim and the pump shell.

[0006] The electromagnetic suppression technology represented by the invention patent (CN119329728A) uses magnetic fields to generate Ampere force to hinder the leakage of conductive fluids such as seawater. However, this technology has obvious limitations: (1) its effectiveness is highly dependent on the electrical conductivity of the medium, and for media such as oil-gas-water mixtures with variable or non-conductive electrical conductivity, its suppression effect will decrease sharply or even fail completely; (2) this technology is essentially a "flow resistance" rather than a "seal", which applies a reverse force field to the leakage path to reduce the leakage amount, relies on the electrical conductivity of the medium, and cannot achieve zero leakage.

[0007] Magnetic fluid sealing technology provides a new solution to the above challenges. However, how to successfully transplant the magnetic fluid sealing technology from traditional shaft sealing to the impeller rim sealing of a multiphase pump and solve the survival and stability problems in multiphase abrasive media constitutes the core starting point of the present application. Summary of the Invention

[0008] The purpose of this invention is to provide a magnetohydrodynamic (MHD) sealed impeller structure that suppresses leakage at the impeller tip clearance. This overcomes the technical obstacles that MHD sealing structures cannot be applied to large-sized annular gaps at the impeller rim and are easily invaded and damaged by solid particles in multiphase abrasive media. It utilizes the self-positioning characteristics of magnetohydrodynamics under a gradient magnetic field to form a dynamic, adaptive, and particle-resistant liquid sealing interface between the impeller rim and the pump casing, fundamentally eliminating physical leakage, achieving zero-leakage operation, and improving the hydraulic efficiency and stability of the axial flow pump unit.

[0009] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0010] A magnetic fluid sealing rim impeller structure for suppressing tip clearance leakage includes a pump casing with a pump inlet and a pump outlet. Blades are disposed inside the pump casing, and a blade cover plate is disposed around the blade. The blade cover plate is fixedly connected to the outer periphery of the blade and there is no gap between them. The blade cover plate rotates together with the blade. The blade cover plate and the pump casing have a sealing gap in the radial direction, and one or more magnetic fluid sealing rings are disposed in the sealing gap along the axial direction.

[0011] A ring-shaped magnetic structure is provided on the outer wall of the pump casing at the position corresponding to the magnetic fluid sealing ring, and a ring-shaped magnetic focusing structure is provided on the inner wall of the pump casing at the position corresponding to the magnetic fluid sealing ring. The corresponding magnetic focusing structure and the magnetic structure form a closed magnetic circuit, thereby forming a gradient magnetic field at the sealing gap. Under the action of the gradient magnetic field, the magnetic fluid is adsorbed and positioned in the corresponding area of ​​the sealing gap, forming a series of continuous and stable magnetic fluid sealing rings that match the shape of the sealing gap.

[0012] Furthermore, the magnetic structure is a ring-shaped permanent magnet ring, which is fixedly connected to the outer wall of the pump casing.

[0013] Furthermore, the permanent magnet ring is concentrically arranged with the pump housing, and the inner ring of the permanent magnet ring is fixedly connected to the outer wall of the pump housing.

[0014] Furthermore, the magnetic focusing structure is an annular magnetic ring, which is fixedly connected to the inner wall of the pump casing.

[0015] Furthermore, the magnetic ring is concentrically arranged with the pump housing, and the outer ring of the magnetic ring is fixedly connected to the inner wall of the pump housing.

[0016] Furthermore, the magnetic ring is made of a highly permeable material.

[0017] Furthermore, the blade cover plate and the pump casing are concentrically arranged, so that the blade cover plate and the pump casing have equally spaced sealing gaps in the radial direction.

[0018] The beneficial effects of this invention are:

[0019] 1. This invention achieves zero-leakage dynamic sealing in multiphase abrasive media. Solving the fluid leakage and efficiency reduction problems caused by impeller tip clearance in existing axial flow pumps is the core technical problem this invention addresses. Overcoming the technical obstacles that magnetohydrodynamic (MHD) sealing structures cannot be applied to large-sized annular gaps in impeller rims and are easily intruded and damaged by solid particles in multiphase abrasive media, this invention proposes a rim structure based on MHD sealing technology. This structure utilizes the self-positioning characteristics of MHD under a gradient magnetic field to form a dynamic, adaptive, and particle-resistant liquid sealing interface between the impeller and the pump casing, achieving zero-leakage operation and improving the hydraulic efficiency and stability of the axial flow pump unit.

[0020] 2. This invention solves the problems of wear resistance and long service life of seals in media containing solid particles, overcoming the shortcomings of traditional mechanical seals and packing seals in media containing particles, which are prone to wear and failure. Compared with the erosion risk faced by magnet assemblies exposed to the flow channel, this structure utilizes the non-contact characteristics and fluid self-healing properties of magnetic fluid seals to give the sealing interface excellent particle tolerance and anti-contamination ability, avoiding performance degradation and frequent maintenance caused by the wear of the seal itself, and significantly extending the service life of the equipment under harsh operating conditions.

[0021] 3. This invention solves the lubrication and friction control problem in the impeller tip clearance area. It addresses the friction loss and temperature rise caused by poor lubrication in the impeller tip area of ​​axial flow pumps. The excellent lubrication characteristics of the magnetohydrodynamic fluid form a lubricating film in the sealing gap, effectively reducing friction loss and temperature rise at the impeller-pump casing clearance, further improving the reliability and energy efficiency of the axial flow pump under high-speed and high-pressure conditions.

[0022] 4. This invention solves the problems of flow stability and high-efficiency range expansion under varying operating conditions. It addresses issues such as increased flow instability and the appearance of a "hump" in the head characteristic curve of axial flow pumps under low-flow conditions due to increased impeller tip clearance during operation. The proposed sealing structure possesses excellent pressure adaptability, automatically adjusting its shape to maintain effective sealing under different head and speed conditions. This fundamentally suppresses the generation and changes in impeller tip leakage, thereby stabilizing the internal flow field, preventing head drops, and significantly expanding the high-efficiency and stable operating range of the axial flow pump.

[0023] 5. This invention achieves an energy-saving and compact sealing structure without external dependence, solving the problems of traditional active sealing or lubrication systems that rely on external pressurization devices, complex pipelines, and external energy sources, resulting in complex structures, high energy consumption, and numerous potential failure points. This invention provides a completely passive sealing solution. This structure relies on a permanent magnet to provide a steady-state magnetic field, eliminating the need for additional pressurization devices or external lubrication systems. It features a simple structure, low energy consumption, and reduces maintenance costs while achieving a green and efficient development direction for equipment.

[0024] 6. This invention solves the leakage problem, thus preventing the escape of toxic, harmful, or valuable substances that could cause greater economic losses, reducing environmental pollution risks and economic losses, and achieving the requirements of green environmental protection and sustainable development.

[0025] 7. This invention abandons the traditional grooved magnetic circuit of a rotating shaft and innovatively constructs a magnetic circuit system suitable for the annular planar gap between the impeller rim and the pump casing. This system consists of an annular permanent magnet assembly arranged on the outer wall of the pump casing and an annular protruding magnetic focusing structure machined on the inner wall of the pump casing. The magnetic focusing structure is made of a high-permeability material, and its core function is to efficiently concentrate the magnetic flux of the permanent magnet, thereby forming a circumferentially uniform, high-intensity gradient magnetic field with concentrated strength throughout the entire annular gap between the impeller rim and the pump casing. This magnetic field design allows the magnetic fluid to stably occupy and seal the entire impeller tip gap.

[0026] 8. This invention utilizes a magnetically focused structure to fill and firmly adsorb magnetic fluid into the gaps, forming one or more continuous and stable liquid "O"-ring seals that rotate synchronously with the impeller. This liquid sealing ring fundamentally eliminates the physical impeller tip clearance, achieving zero-leakage dynamic sealing for multiphase media. Simultaneously, this magnetic fluid layer acts as a natural lubricating film, transforming the dry or mixed friction between the impeller cover and the pump casing into liquid friction, effectively reducing friction loss and temperature rise. It is particularly suitable for media containing particles, avoiding direct scraping and wear caused by solid particles.

[0027] 9. This invention utilizes the unique properties of magnetic fluids, which combine fluidity and ferromagnetic response, to endow the sealing ring with inherent pressure self-adaptive capability. When system pressure fluctuates (such as during pressurization or depressurization), the pressure difference acting on the magnetic fluid sealing ring changes, forcing the magnetic fluid to tend to displace; simultaneously, the gradient magnetic field it is in exerts a restoring magnetic force on it. Through the automatic adjustment of the magnetic fluid's position and shape in a non-uniform magnetic field, a new balance between magnetic force and fluid pressure is quickly established, thereby maintaining the integrity and sealing effectiveness of the sealing interface under different operating conditions, fundamentally avoiding seal failure caused by pressure shocks.

[0028] 10. The entire sealing system of this invention relies entirely on the static magnetic field provided by the permanent magnet, requiring no external energy supply, pressurization device, or complex lubrication pipeline. This design achieves integrated sealing and lubrication functions, with a compact structure and zero energy consumption, completely solving the problems of complex structure, high energy consumption, and reliance on external support in traditional sealing systems. It is particularly suitable for harsh environments such as deep sea and open ocean where maintenance is difficult.

[0029] 11. This invention effectively solves the problem of leakage caused by impeller tip clearance and the resulting performance degradation of axial flow pumps by introducing a magnetic fluid sealing mechanism, achieving the goal of eliminating impeller tip clearance in axial flow pumps. By magnetically controlling the magnetic fluid to respond to a magnetic field, a liquid sealing ring is formed between the impeller cover plate and the pump casing, improving the operating efficiency, operational stability, and service life of the axial flow pump, while effectively reducing maintenance costs. This is of great significance for promoting technological progress and industrial upgrading in related fields. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of the present invention;

[0031] Figure 2 This is a side view of the present invention;

[0032] Figure 3 This is a comparative diagram of the pressure diagrams of the devices of the present invention and the prior art, wherein (a) is the solution of the present invention and (b) is the solution of the prior art;

[0033] Figure 4 This is a graph showing the ratio of flow rate to efficiency between the present invention and existing technologies;

[0034] Figure 5 This is the rotational friction diagram of the present invention.

[0035] In the diagram: 1-Pump casing; 2-Permanent magnet ring; 3-Blade cover plate; 4-Blade; 5-Magnetic fluid sealing ring; 6-Magnetic ring.

[0036] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the invention. To better illustrate this embodiment, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. Detailed Implementation

[0037] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0038] like Figure 1 and Figure 2 As shown, this embodiment discloses a magnetic fluid sealing rim impeller structure for suppressing tip clearance leakage, including a pump casing 1, a permanent magnet ring 2, a blade cover plate 3, blades 4, a magnetic fluid sealing ring 5, and a magnetic focusing ring 6. Through the synergistic effect of the above components, while achieving efficient fluid transportation, the sealing performance, operating efficiency, and service life of the axial flow pump are improved, and it is suitable for complex application scenarios such as media containing impurities, mixed oil and gas transportation, and variable operating conditions.

[0039] This invention combines the magnetofluid properties of magnetic fluids to design a bladeless top-gap magnetic fluid sealed rim impeller structure. Based on a bladeless top-gap impeller, this structure introduces magnetic fluid into the gap between the rim and the casing through a special magnetic circuit distribution. The impeller's circumferential motion provides lubrication and hinders the radial flow of the transported medium, achieving a novel structure with zero leakage and low wear, thus improving the working efficiency of axial flow pumps.

[0040] The following provides a detailed description of the specific structure of each component.

[0041] Pump casing 1 serves as the main body of the axial flow pump, acting as the pressure-bearing and support structure. The two axial ends of pump casing 1 are the pump inlet and the pump outlet, respectively.

[0042] The pump casing 1 contains blades 4. As the core working component of the axial flow pump, blades 4 are responsible for transferring mechanical energy to the fluid, propelling the medium from a low-pressure area to a high-pressure area. During operation, the impeller rotates at high speed, continuously pushing the water upwards under the lift generated by the blades, causing the water to flow out along the pump outlet. With the impeller constantly rotating, water is continuously pressurized to a higher position.

[0043] A blade cover plate 3 is provided around the blade 4. The blade cover plate 3 is fixedly connected to the outer periphery of the blade 4 and there is no gap between them. The blade cover plate 3 rotates together with the blade 4.

[0044] The blade cover plate 3 and the pump casing 1 have a sealing gap in the radial direction, and one or more magnetic fluid sealing rings 5 ​​are provided in the sealing gap along the axial direction.

[0045] In this embodiment, the blade cover plate 3 and the pump casing 1 are arranged concentrically, so that the blade cover plate 3 and the pump casing 1 have equally spaced sealing gaps in the radial direction.

[0046] A ring-shaped magnetic structure is provided on the outer wall of the pump casing 1 at the position corresponding to the magnetic fluid sealing ring, and a ring-shaped magnetic focusing structure is provided on the inner wall of the pump casing 1 at the position corresponding to the magnetic fluid sealing ring. The corresponding magnetic focusing structure and magnetic structure form a closed magnetic circuit, thereby generating a high-intensity gradient magnetic field at the sealing gap. As a functional medium that combines the fluidity of liquid and the magnetic response characteristics, the magnetic fluid is adsorbed and positioned in the sealing gap area under the action of the magnetic field, forming a series of continuous and stable magnetic fluid sealing rings 5 ​​(the magnetic fluid sealing rings are liquid "O"-shaped sealing rings) that match the shape of the sealing gap.

[0047] In this embodiment, the magnetic structure is a ring-shaped permanent magnet ring 2, which is used to generate a strong and stable static magnetic field, providing an excitation source for the entire sealing system without the need for external power supply. The permanent magnet ring 2 is concentrically arranged with the pump housing 1, and the inner ring of the permanent magnet ring 2 is fixedly connected to the outer wall of the pump housing.

[0048] In this embodiment, the magnetic focusing structure is a ring-shaped magnetic focusing ring 6, which is made of a highly permeable magnetic material and is used to focus the magnetism and maintain the magnetic field strength. The magnetic focusing ring 6 is concentrically arranged with the pump housing 1, and the outer ring of the magnetic focusing ring 6 is fixedly connected to the inner wall of the pump housing 1.

[0049] The working principle of this invention is as follows:

[0050] The permanent magnet ring 2 generates a strong and stable static magnetic field. A magnetic focusing ring 6 is also provided within the sealing gap, causing the magnetism to concentrate in the focusing ring 6. This focusing ring 6 and the permanent magnet ring 2 form a closed magnetic circuit, significantly enhancing and concentrating the magnetic induction intensity, creating a high-intensity gradient magnetic field at the sealing gap. Magnetic fluid is filled into the sealing gap formed by the pump casing 1 and the blade cover plate 3. Under the influence of the high-gradient magnetic field established by the focusing ring 6 and the permanent magnet ring 2, the magnetic fluid sealing ring 5 is subjected to a strong magnetic force, firmly adsorbed and positioned within this area, forming a series of continuous and stable liquid "O"-shaped sealing rings that perfectly match the structural morphology. This sealing ring completely blocks the leakage path of the fluid through the gap, achieving true gapless operation and zero-leakage sealing.

[0051] like Figure 3 As shown in the figure, (a) represents the solution of the present invention, in which the blade and the blade cover are connected together, and the tip clearance between the blade and the blade cover is 0. (b) represents the solution of the prior art, in which there is no blade cover, and there is a tip clearance between the blade and the pump casing.

[0052] pass Figure 3 The comparison shows that when the system pressure fluctuates (such as pressure increase or decrease caused by changes in operating conditions), the magnetic fluid sealing ring 5 can adaptively deform and adjust its position under the constraint of the magnetic field, dynamically maintaining the integrity and fit of the sealing interface, avoiding seal failure caused by pressure difference impact, and demonstrating excellent pressure adaptive characteristics. Because the magnetic fluid sealing ring can dynamically fit the gap profile, it can maintain a good sealing state even when the inlet pressure or flow fluctuates, effectively suppressing the increase of leakage flow, thereby avoiding a decrease in volumetric efficiency.

[0053] like Figure 4 (The horizontal axis represents flow rate, and the vertical axis represents efficiency.) As shown in the figure, the purple line represents the solution of the present invention, that is, the blade and the blade cover are connected together, and the blade tip gap between the blade and the blade cover is 0. Figure 4 The medium green line represents the existing technology solution (the existing technology does not have a blade cover plate, and there is a blade tip gap between the blade and the pump casing), and the blade tip gap between the blade and the pump casing is 0.81cm. Figure 4The blue line represents the prior art solution (the prior art has no blade cover, and there is a tip clearance between the blade and the pump casing), and the tip clearance between the blade and the pump casing is 0.5 cm. The red line represents the prior art solution (the prior art has no blade cover, and there is a tip clearance between the blade and the pump casing), and the tip clearance between the blade and the pump casing is 1.08 cm. The black line represents the prior art solution (the prior art has no blade cover, and there is a tip clearance between the blade and the pump casing), and the tip clearance between the blade and the pump casing is 1.35 cm.

[0054] pass Figure 4 As can be seen from the comparison, compared with traditional axial flow pumps with impeller tip clearance, the axial flow pump with the magnetohydrodynamic sealing structure adopted in this invention has higher operating efficiency, and its effective power utilization can stably reach over 85%. This advantage significantly broadens the high-efficiency operating range of the axial flow pump and improves its overall performance and energy utilization efficiency under varying operating conditions.

[0055] The magnetic fluid sealing ring 5 also functions as a lubricant in the sealing gap. For example... Figure 5 As shown, the liquid film formed can significantly reduce the frictional resistance and wear between rotating and stationary parts, making the frictional loss and frictional torque of the sealing structure almost negligible, which helps to improve the mechanical efficiency of the axial flow pump.

[0056] This invention is completely different from the existing "groove-type" magnetic circuit of rotating shafts. By arranging annular permanent magnets on the outer wall of the pump casing and innovatively setting annular protruding magnetic focusing structure on the inner wall of the pump casing, a circumferentially uniform, high-intensity gradient magnetic field environment is constructed in the entire annular plane gap between the impeller cover plate and the pump casing.

[0057] Magnetic fluid possesses both the fluidity of liquids and the magnetism of solid magnetic materials. Under the influence of this magnetic field, the magnetic fluid is adsorbed and stably held within the gap, forming a continuous liquid "O"-ring seal that rotates synchronously with the impeller. This sealing ring fundamentally eliminates the physical impeller tip clearance, achieving zero-leakage dynamic sealing for multiphase media. This magnetic fluid layer also serves as a highly efficient lubricating film, converting the solid friction between the impeller and the pump casing into liquid friction, thus integrating "sealing and lubrication."

[0058] The advantage of this sealing mechanism lies in its inherent pressure adaptability. Utilizing the magnetic-force balance principle of magnetic fluid in a gradient magnetic field, when system conditions change (such as pressurization or depressurization), the sealing ring can automatically and instantaneously adjust its shape and distribution, always maintaining the integrity and fit of the sealing interface. This dynamic intelligent response characteristic effectively ensures the pump's operational stability under varying loads and suppresses flow instability under low-flow conditions, a feature not found in conventional static sealing structures. Furthermore, relying on its magnetic field design, this device requires no external power supply, has a simple structure, and a long service life, exhibiting high adaptability and reliability, especially in the transportation of mixed oil and gas, silt-containing fluids, and other complex media.

[0059] This invention designs an impeller rim sealing structure based on a special magnetic circuit distribution by combining the magnetofluid properties of magnetic fluids. Compared to existing electromagnetic suppression technologies, which can only "impede" leakage flow to a limited extent through electromagnetic force and cannot form a physical seal, and other existing magnetofluid sealing technologies, due to their structural characteristics, are difficult to maintain stably in open gaps in the impeller rim and under multiphase particulate conditions, this structure, through an innovative intermittent magnetic circuit, forms a dynamically adaptive liquid sealing barrier in the gap between the rim and the pump casing, fundamentally eliminating physical leakage channels and achieving "zero leakage" operation in multiphase media. This not only completely suppresses the generation of leakage flow at the impeller tip but also solves the problem of erosion of the sealing surface by particulate media, overcoming the pain point of inevitable wear and failure of traditional mechanical seals in sandy media, and achieving long-term sealing under harsh media conditions.

[0060] Secondly, this liquid barrier also possesses excellent lubrication capabilities, effectively reducing friction, wear, and temperature rise between the impeller and stationary components. It integrates sealing and lubrication functions, fundamentally solving the wear problem caused by poor lubrication in the impeller tip area, and significantly improving the mechanical efficiency and operational reliability of the axial flow pump under high-speed and high-pressure conditions. Traditional gap or passive leakage suppression technologies experience drastic performance fluctuations when operating conditions change. This sealing structure has inherent pressure adaptability; when system pressure fluctuates, the magnetic fluid automatically adjusts its shape and distribution under the influence of a magnetic field, maintaining the integrity of the seal. This effectively avoids seal failure caused by pressure shocks and suppresses flow instability and head drop under low-flow conditions, broadening the range of efficient and stable operation.

[0061] This invention comprehensively improves the volumetric and mechanical efficiency of axial flow pumps by reducing leakage and friction losses, ultimately achieving a simultaneous leap in operational stability and equipment lifespan. The entire sealing system operates using permanent magnets, requiring no external energy source, pressurization device, or lubrication pipeline, achieving zero-energy sealing. This fully passive design features a compact structure and long maintenance-free cycle, significantly reducing system complexity, operating energy consumption, and total lifecycle costs, making it particularly suitable for energy-intensive and difficult-to-maintain applications such as deep-sea and offshore environments.

[0062] The above embodiments are only used to illustrate and not limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention without departing from the spirit and scope of the present invention. Any modifications or partial substitutions should be covered within the scope of the claims of the present invention.

[0063] If the terms "first" or "second" are used in this document to define components, those skilled in the art should know that the use of "first" or "second" is merely for the convenience of describing the invention and simplifying the description, and unless otherwise stated, the above terms have no special meaning.

[0064] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" 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 this invention and simplifying the description, and are not intended to 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 this invention.

[0065] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

Claims

1. A magnetohydrodynamic sealing rim impeller structure for suppressing tip clearance leakage, comprising a pump casing having a pump inlet and a pump outlet, and blades disposed within the pump casing, characterized in that: The blade is surrounded by a blade cover plate, which is fixedly connected to the outer edge of the blade and there is no gap between them. The blade cover plate rotates with the blade. The blade cover plate and the pump casing have a sealing gap in the radial direction, and one or more magnetic fluid sealing rings are provided in the sealing gap along the axial direction. A ring-shaped magnetic structure is provided on the outer wall of the pump casing at the position corresponding to the magnetic fluid sealing ring, and a ring-shaped magnetic focusing structure is provided on the inner wall of the pump casing at the position corresponding to the magnetic fluid sealing ring. The corresponding magnetic focusing structure and the magnetic structure form a closed magnetic circuit, thereby forming a gradient magnetic field at the sealing gap. Under the action of the gradient magnetic field, the magnetic fluid is adsorbed and positioned in the corresponding area of ​​the sealing gap, forming one or more continuous and stable magnetic fluid sealing rings that match the shape of the sealing gap. The magnetic structure is a ring-shaped permanent magnet ring, which is fixedly connected to the outer wall of the pump casing. The magnetic focusing structure is a ring-shaped magnetic focusing ring, which is fixedly connected to the inner wall of the pump casing with the same core. The magnetic ring is made of a highly permeable material.

2. The magnetohydrodynamic sealing rim impeller structure for suppressing tip clearance leakage according to claim 1, characterized in that: The permanent magnet ring is concentrically arranged with the pump casing, and the inner ring of the permanent magnet ring is fixedly connected to the outer wall of the pump casing.

3. The magnetohydrodynamic sealing rim impeller structure for suppressing tip clearance leakage according to claim 1, characterized in that: The magnetic ring is concentrically arranged with the pump casing, and the outer ring of the magnetic ring is fixedly connected to the inner wall of the pump casing.

4. The magnetohydrodynamic sealing rim impeller structure for suppressing tip clearance leakage according to claim 1, characterized in that: The blade cover plate and the pump casing are concentrically arranged, so that the blade cover plate and the pump casing have equally spaced sealing gaps in the radial direction.

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