High-rotating-speed multi-stage centrifugal pump supported by air film

Abstract

The invention relates to a high-rotating-speed multi-stage centrifugal pump supported by an air film. Efficient liquid conveying is achieved through unique design. A motor in the driving mechanism is powered on, power is stably transmitted to a pump shaft through a coupler, and a multi-stage impeller is driven to rotate at a high speed. Liquid flows in from the water inlet in the bottom of the pump body, obtains speed energy under the centrifugal force of the impeller and is converted into pressure energy through the multi-stage guide vanes, and efficient conveying is achieved. Gas is stored in a gas chamber in a stator of the air bearing and forms an air film through a multi-stage shrinkage nozzle to support a pump shaft, friction resistance is reduced, and high rotating speed is adapted. The rubidium magnet in the rotor shaft sleeve interacts with the magnetic fluid cavity, so that sealing is enhanced, and adjustment is assisted. The mechanical seal and the oil seal prevent liquid leakage and protect the air bearing. An overflow cavity and an overflow groove adjust pressure in the pump, a water inlet filter screen intercepts impurities, and a pull rod stabilizing structure is reinforced. The centrifugal pump effectively solves the problem of a traditional centrifugal pump at a high rotating speed and has the advantages of high efficiency, stability, long service life and the like.

Description

Technical Field

[0001] The present invention relates to the field of multistage centrifugal pumps, and particularly to a high-speed multistage centrifugal pump supported by an air film. Background Art

[0002] Multistage centrifugal pumps are mechanical devices widely used in industrial and civil fields, mainly for transporting liquid media. Due to their efficient, stable, and reliable working performance, multistage centrifugal pumps have been widely applied in industries such as petrochemical, power, water supply, and drainage. In industrial production, cost control has always been an important goal pursued by enterprises. For multistage centrifugal pumps, a common approach is to reduce the number of guide vanes and impellers to cut costs. However, this inevitably reduces the number of pump stages, thereby affecting the pump pressure output. To ensure sufficient pump pressure even with fewer stages, increasing the motor speed becomes an inevitable choice, and the motor speed often needs to reach tens of thousands of revolutions.

[0003] During the high-speed operation of centrifugal pumps, the vibration problem has become a key technical bottleneck affecting their performance, lifespan, and safety. First of all, under ultra-high-speed conditions, the rotor is extremely prone to severe centrifugal imbalance due to machining errors, installation deviations, or uneven moments of inertia, resulting in periodic excitation. The high-speed rotation exponentially amplifies tiny disturbances through centrifugal force, causing axial and radial displacements and forming a vibration amplification effect. Especially at both ends of the rotor, due to the influence of the structural stiffness boundary effect, it is more likely to become a vibration concentration area, thereby continuously impacting the support system.

[0004] To reduce frictional losses and avoid wear and heat accumulation caused by mechanical contact, non-contact support structures have become the mainstream solution. Air film bearings (including hydrostatic and hydrodynamic types) can be a good direction due to their good damping performance and low starting friction. However, under high-speed conditions, air bearings are independent components that support the rotor in the form of additional modules, and they are prone to assembly errors, dynamic imbalance, etc. relative to the pump body, especially exacerbating vibration during high-speed operation. On the one hand, the bearing capacity and stiffness of the air film are limited, and it is easy to produce uneven film thickness under the action of external disturbances (such as pressure fluctuations, unstable air intake, environmental thermal changes); on the other hand, the instability of gas flow may cause the film layer to rupture, resulting in instantaneous contact, increased vibration, and even equipment damage.

[0005] These problems severely restrict the efficient and stable operation of multistage centrifugal pumps at high speeds and urgently require innovative technologies to solve them. Summary of the Invention

[0006] (I) Technical Problems to be Solved Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a high-speed multi-stage centrifugal pump supported by an air film, which solves the problems existing in the existing technology. By directly integrating the structure of the air bearing into the pump body bracket, an integrated support system with the pump body is formed, which has the remarkable effects of reducing assembly errors, improving structural coaxiality, and enhancing dynamic stability. Different from the traditional installation of the air bearing as an independent module outside the pump body, the integrated design of the present invention avoids mechanical deviations and structural discontinuities caused by the intermediate connection interface, and significantly improves the rotation accuracy and stiffness of the rotor at high speeds. This design effectively solves the technical problems commonly encountered in the application of traditional air bearings in high-speed centrifugal pumps, such as difficult coaxiality guarantee, complex assembly, and easy excitation of vibration during operation.

[0007] At the same time, through the precisely designed pressure-dividing air cavity, main air cavity, and annular, multi-stage contracting nozzle structure, it is ensured that the jet airflow can uniformly and stably form a high-stiffness air film, effectively supporting the rotor to stably levitate at high speeds and reducing air film vibration and fluid disturbance. In addition, permanent magnets are embedded inside the rotor, and magnetic poles in the form of an annular Halbach magnetic array are arranged inside the bracket. In cooperation with the conductive lining plate, passive magnetic damping is achieved by using the eddy current effect, thereby further enhancing the magnetic levitation support and vibration suppression effects. In this way, through the organic combination of air film support, magnetic levitation, and magnetic damping technologies, the present invention not only greatly improves the operating stability and energy efficiency of the centrifugal pump at high speeds, but also effectively reduces equipment wear and maintenance costs, significantly extends the service life of the equipment, and provides a solid technical guarantee for the efficient, stable, and low-noise operation of the centrifugal pump.

[0008] (II)Technical solutions To achieve the above object, the present invention provides the following technical solutions: A high-speed multi-stage centrifugal pump supported by an air film, including a bracket, a driving mechanism and a pump body are respectively fixed at the upper and lower ends of the bracket, a pressure-dividing air cavity and a main air cavity are arranged inside the bracket, a nozzle is penetrated through the inner edge cavity wall of the main air cavity, and a rotor is sleeved inside the main air cavity. Preferably, the nozzles are distributed in a ring along the cavity wall of the main air cavity. The nozzles are of a symmetrical conical structure as a whole, provided with three gradually contracting conical sections, the contraction angle of each section is 5° - 10°, and a throttle hole is arranged at the end section of the nozzle. Preferably, permanent magnets are embedded inside the rotor, and multiple groups of magnetic poles are embedded inside the bracket and arranged in an annular Halbach magnetic array. The magnetic poles are arranged at the step positions at the upper and lower ends of the rotor, and a conductive lining plate is arranged on the outer edge of the magnetic poles.

[0009] Preferably, an air valve and an air duct are arranged on the side surface of the bracket, and the air duct is connected to the pressure-dividing air cavity.

[0010] Preferably, the upper and lower ends of the pressure-dividing air cavity and the main air cavity are arc-shaped, and gratings are arranged in an array at the upper and lower ends of the connection between the pressure-dividing air cavity and the main air cavity.

[0011] Preferably, an overflow chamber is provided at the inner bottom of the support, and an overflow groove is provided at the bottom of the overflow chamber.

[0012] Preferably, the driving mechanism includes a motor, a coupling is fixed to the end of the output shaft of the motor, and a pump shaft is fixed to the lower end of the coupling.

[0013] Preferably, the rotor and the pump shaft are in interference fit.

[0014] Preferably, the pump body includes a guide vane fixed to the lower end of the support and an impeller installed on the pump shaft, and a water inlet is provided at the bottom of the pump body.

[0015] Preferably, a grease seal is provided at the contact between the upper end of the overflow chamber and the pump shaft.

[0016] Preferably, a mechanical seal is fixed to the outer edge of the pump shaft, and the mechanical seal is clamped between the support and the impeller.

[0017] Preferably, a strengthening tie rod is fixed between the support and the water inlet.

[0018] (III) Beneficial effects The purpose of the present invention is to provide a high-speed multi-stage centrifugal pump supported by an air film. In this application, the stator of the traditional air bearing is directly integrated into the pump body, achieving high coaxiality and structural compactness between the rotor and the support, significantly reducing the unbalanced vibration caused by assembly errors. At the same time, the optimized design of the pressure-dividing air chamber and the main air chamber, combined with the precise arrangement of the annular and multi-stage convergent nozzles, enables the jet airflow to uniformly and stably form a high-rigidity air film, effectively supporting the rotor to stably levitate at high speeds and reducing the vibration risk caused by air film fluctuations and fluid disturbances. In addition, this application utilizes the synergistic effect of the permanent magnets embedded in the rotor and the magnetic poles arranged in a magnetic array within the support to form a strong magnetic levitation support at the upper and lower ends of the rotor, not only sharing the support load of the air bearing but also achieving an eddy current damping effect by setting a conductive lining plate on the outer edge of the magnetic pole, automatically absorbing and suppressing the rotor vibration, thereby further reducing the resonance phenomenon and the noise level. Secondly, the Halbach magnetic array and the air film injection area overlap spatially in structure. When the rotor rotates, the alternating magnetic field and the high-speed shear air film flow field are mutually coupled, generating a magnetohydrodynamic (MHD) effect in the local micro-conductive air film. This effect restricts the expansion of the disturbance vortices inside the air film at the microscale, applying constraints to the micro-vortex structure through the Lorentz force, thereby significantly enhancing the stability and continuity of the air film support, improving the anti-disturbance ability of the system under high-speed operation, showing a non-linear stability effect under the multi-field coupling of structure - magnetic field - fluid, and having technical advantages beyond traditional air bearings or magnetic levitation independent structures.

[0019] In summary, the structure of this application combines the advantages of air film support, magnetic levitation, and magnetic damping technologies, significantly improving the operating stability and energy efficiency of centrifugal pumps under high-speed conditions, reducing mechanical wear and maintenance costs, while extending the service life of the equipment, providing a solid technical guarantee for efficient, stable, and low-noise operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the whole of the present invention.

[0021] Figure 2 It is a sectional view of the whole in the present invention.

[0022] Figure 3 is Figure 2 an axonometric view of part A in the sectional view of the whole.

[0023] Figure 4 is Figure 2 an enlarged view of part B in the sectional view of the whole.

[0024] Figure 5 It is a sectional view of the bracket and the driving mechanism in the present invention.

[0025] Figure 6 is Figure 5 an enlarged view of part C in the sectional view of the bracket and the driving mechanism.

[0026] Figure 7 It is a half-sectional view of the bracket in the present invention.

[0027] Figure 8 is Figure 7 an enlarged view of part D in the half-sectional view of the bracket.

[0028] Figure 9 It is a schematic diagram of the arrangement of magnetic poles in the present invention.

[0029] In the figure: 1 - bracket, 2 - driving mechanism, 3 - pump body, 11 - pressure-dividing air cavity, 12 - main air cavity, 13 - nozzle, 14 - rotor, 15 - throttle hole, 16 - magnetic pole, 17 - conductive lining, 18 - air valve, 19 - air duct, 20 - grille, 111 - overflow cavity, 112 - water outlet, 141 - permanent magnet, 21 - motor, 22 - coupling, 23 - pump shaft, 24 - mechanical seal, 25 - oil seal, 31 - guide vane, 32 - impeller, 33 - water inlet, 34 - strengthening tie rod. DETAILED DESCRIPTION OF THE INVENTION

[0030] Next, the attached drawings in the examples of the present invention will be combined Figures 1-9The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] The present invention provides a technical solution: a high-speed multi-stage centrifugal pump supported by an air film, including a bracket 1. A driving mechanism 2 and a pump body 3 are respectively fixed at the upper and lower ends of the bracket 1. The bracket 1 is the basic support structure of the entire centrifugal pump, which plays a role in connecting and fixing other main components. Fixing the driving mechanism 2 and the pump body 3 at its upper and lower ends respectively ensures the relative position stability between these two key components, enabling the entire centrifugal pump to maintain the integrity and stability of the structure during operation, and avoiding affecting the normal operation of the pump due to component shaking or displacement. The driving mechanism 2 provides the power source for the centrifugal pump to ensure its normal operation. The motor 21 in the driving mechanism generates rotational power, which is transmitted to the coupling 22 through the output shaft. The coupling 22 then smoothly transmits the power of the motor to the pump shaft 23, thereby driving the pump shaft to rotate and providing rotational power for the impeller 32 in the pump body 3, enabling the centrifugal pump to achieve the liquid transportation function. The pump body 3 is the core component for realizing the liquid transportation function. The overflow chamber 111 is located inside the bracket 1, which mainly plays a role in buffering and regulating pressure. During the operation of the centrifugal pump, there may be situations of unstable liquid flow rate or pressure fluctuation. The overflow chamber can accommodate the excess liquid to avoid excessive pressure inside the pump and ensure the safe operation of the pump. When the pressure inside the pump is too high, part of the liquid can flow into the overflow chamber; when the pressure decreases, the liquid in the overflow chamber can flow back into the working flow path of the pump to maintain the stable operation of the pump.

[0032] A pressure-dividing air chamber 11 and a main air chamber 12 are arranged inside the bracket 1. A nozzle 13 is penetrated through the inner edge chamber wall of the main air chamber 12. A rotor 14 is sleeved inside the main air chamber 12. The pressure-dividing air chamber 11 mainly plays a role in regulating and distributing gas pressure. During the operation of the high-speed multi-stage centrifugal pump, the pressure of the gas source fluctuates or is unstable. The pressure-dividing air chamber can preliminarily regulate and buffer the incoming gas pressure, adjust the gas pressure to a suitable range, and provide gas with stable and appropriate pressure for the subsequent main air chamber. The main air chamber 12 is the main storage and transportation space for gas. It receives the gas with adjusted pressure and flow rate from the pressure-dividing air chamber, stores it centrally, and then transports it through the nozzle on the inner edge chamber wall to the area where an air film needs to be formed. The main air chamber can further stabilize the gas pressure, keep the gas in a relatively stable pressure state before reaching the nozzle, so as to ensure that the gas ejected from the nozzle has stable parameters, which is beneficial to form a uniform and stable air film.

[0033] The upper and lower ends of the pressure-dividing air cavity 11 and the main air cavity 12 are arc-shaped. At the upper and lower ends of the connection between the pressure-dividing air cavity 11 and the main air cavity 12, a grille 20 is arranged in an array. The pressure-dividing air cavity 11 receives the gas input by the air inlet channel 19, and the arc-shaped structure in the cavity slows down the airflow impact, making the gas evenly distributed and preliminarily pressurized before entering the main air cavity 12. The arc-shaped design can avoid the formation of dead corners of the airflow in the cavity, ensuring that the air supply pressure of each nozzle 13 in the main air cavity 12 is consistent. The grille 20 array at the connection between the pressure-dividing air cavity 11 and the main air cavity 12 can evenly guide the gas in the pressure-dividing air cavity 11 to the main air cavity 12, avoiding airflow turbulence and ensuring the air supply stability of the nozzle 13.

[0034] The nozzles 13 are distributed along the cavity wall of the main air cavity 12 in a ring shape. The nozzles 13 as a whole are of a symmetric conical structure, provided with three gradually shrinking conical sections, and the shrinking angle of each stage is 5°-10°. A throttling hole 15 is arranged at the end section of the nozzle 13; among them, the nozzles 13 as a whole are of a symmetric conical structure and are provided with three gradually shrinking conical sections, and the shrinking angle of each stage is 5°-10°. This special structural design enables the gas, when passing through the nozzle, to continuously increase its flow velocity as the flow channel gradually shrinks. Through multi-stage shrinking, multiple accelerations of the gas can be achieved, and finally the gas is ejected at a relatively high speed. The nozzles distributed along the cavity wall of the main air cavity in a ring shape can evenly eject the gas around the rotor, thereby forming a uniform and stable air film between the rotor and the stator. The air film plays a role in supporting and lubricating the rotor, reducing the friction and wear between the rotor and the stator, reducing energy loss, and improving the efficiency and reliability of the pump. The throttling hole 15 is located at the end section of the nozzle. It can further control the flow rate of the accelerated gas. By restricting the flow area of the gas, the throttling hole can precisely adjust the gas flow rate, ensuring that the amount of gas entering the air film area is just right, and avoiding affecting the stability and performance of the air film due to too large or too small gas flow rate. The throttling hole can also play a role in stabilizing the gas pressure. When the gas passes through the throttling hole, a certain pressure drop will be generated, thereby making the gas pressure more stable, which is conducive to forming a stable air film.

[0035] A permanent magnet 141 is embedded inside the rotor 14, and multiple groups of magnetic poles 16 are embedded inside the bracket 1 and arranged in a ring-shaped Halbach magnetic array. The magnetic poles 16 are arranged at the step positions at the upper and lower ends of the rotor 14, and a conductive lining 17 is arranged on the outer edge of the magnetic poles 16.

[0036] First of all, due to reasons such as geometric structure and dynamic load, the upper and lower ends of the rotor are more likely to have vibration and displacement deviation. The traditional air film support may be insufficient in these areas. For this reason, in the present invention, magnetic poles 16 are arranged at the step positions at the upper and lower ends of the rotor. These magnetic poles are arranged in the form of a Halbach magnetic array, as Figure 9As shown, through the magnetic pole arrangement with continuous 90° rotation, the magnetic field is significantly enhanced in the area towards the inside of the rotor (working side), while being weakened in the opposite direction. The high-intensity magnetic field formed in this way can cooperate with the permanent magnet 141 inside the rotor to provide additional magnetic levitation support force for the rotor, thus effectively supplementing and strengthening the effect of the original air film support system.

[0037] Secondly, the enhanced magnetic levitation support can not only share part of the load generated by high-speed operation, reduce the pressure borne by the air film, but also, when the rotor vibrates or deviates, through the "self-centering" effect of the magnetic field, automatically pull the rotor back to the stable working position, further suppressing vibration. In other words, the interaction between the magnetic poles and the permanent magnet forms a non-contact auxiliary support mechanism, which constructs an additional support "barrier" in the upper and lower end areas of the rotor to counteract the unstable factors caused by vibration, thereby improving the dynamic rigidity and stability of the entire system.

[0038] Finally, the conductive lining 17 provided on the outer edge of the magnetic pole 16 further exerts a magnetic damping effect. When the rotor rotates or vibrates at high speed, the change in the magnetic field will generate eddy currents in the conductive lining. These eddy currents in turn generate a magnetic field opposite to the direction of the rotor movement, thus forming a damping force to effectively absorb the vibration energy and reduce the resonance phenomenon. This passive magnetic damping effect can quickly respond and suppress vibration when the rotor is disturbed without additional energy supply, especially in the areas where vibration is more likely to be excited at the upper and lower ends of the rotor, and its effect is particularly significant. The material of the conductive lining 17 is a non-magnetic metal such as copper or aluminum. The principle is that when the rotor vibrates in the magnetic field, the change in the magnetic field will generate eddy currents in the nearby conductor (conductive lining). These eddy currents will form a magnetic field in the opposite direction. According to Lenz's law, this reverse magnetic field will exert a braking force on the rotor movement, thus playing an electromagnetic damping role.

[0039] An air valve 18 and an air duct 19 are provided on the side of the bracket 1, and the air duct 19 is connected to the pressure-dividing air cavity 11. The air valve 18 serves as the switch for gas to enter the system. By adjusting the opening degree of the air valve, the gas flow rate input into the pressure-dividing air cavity 11 can be controlled, thereby adjusting the air pressure in the main air cavity 12 to ensure the stability of the air film between the rotor 14 and the stator. Cooperating with the air duct 19 and the pressure-dividing air cavity 11, the dynamic regulation of the air supply pressure to the main air cavity 12 is realized to meet the air film support requirements under different rotational speeds or loads.

[0040] The pump body 3 includes a multi-stage guide vane 31 fixed to the lower end of the bracket 1 and a multi-stage impeller 32 mounted on the pump shaft 23. An inlet 33 is provided at the bottom of the pump body 3. The guide vane is installed at the lower end of the bracket 1, and its main function is to guide and convert the energy of the liquid passing through the impeller 32. When the liquid obtains kinetic energy after passing through the impeller, the guide vane can adjust the flow direction of the liquid to make it flow more orderly, and at the same time convert part of the kinetic energy of the liquid into pressure energy, increase the pressure of the liquid, and enhance the conveying capacity of the centrifugal pump. The impeller 32 is mounted on the pump shaft 23 and rotates at a high speed as the pump shaft rotates. The impeller does work on the liquid during rotation, enabling the liquid to obtain energy and generate a centrifugal force, thereby throwing the liquid from the center of the impeller to the edge of the impeller, realizing the suction and discharge of the liquid. The setting of the multi-stage impeller can further increase the head and flow rate of the centrifugal pump to meet the usage requirements under different working conditions. The inlet 33 is located at the bottom of the pump body 3 and is the channel for the centrifugal pump to suck the liquid to be conveyed. The liquid enters the pump body through the inlet and then is finally conveyed to the required place through the action of the multi-stage impeller and guide vane.

[0041] An overflow groove is provided at the bottom of the overflow chamber 111. The overflow groove is arranged at the bottom of the overflow chamber 111. When the pressure in the pump is too high or the liquid flow rate is too large, the excess liquid can be discharged from the overflow chamber through the overflow groove, preventing excessive liquid accumulation in the overflow chamber and resulting in too high pressure, so as to ensure that the overflow chamber can normally play the role of buffering and regulating pressure and protect the safe and stable operation of the centrifugal pump.

[0042] A mechanical seal 24 is fixed to the outer edge of the pump shaft 23, and the mechanical seal 24 is clamped between the bracket 1 and the impeller 32. An oil seal 25 is provided at the contact between the upper end of the overflow chamber 111 and the pump shaft 23. The mechanical seal 24 is installed on the outer edge of the pump shaft 23 and clamped between the bracket 1 and the impeller 32. It is a key component to prevent the leakage of the liquid in the pump. When the high-speed multi-stage centrifugal pump is running, the pump shaft rotates at a high speed and the liquid in the pump has a high pressure. The mechanical seal forms an effective seal between the rotating pump shaft and the stationary bracket and impeller through the close fit between the static and dynamic rings and the action of the auxiliary seal. The oil seal 25 is provided at the contact between the upper end of the overflow chamber 111 and the pump shaft 23, mainly used to prevent the liquid in the pump from entering the overflow chamber 111, and at the same time prevent the possible gas or impurities in the overflow chamber from entering the pump body working area in the reverse direction.

[0043] A reinforcing rod 34 is fixed between the bracket 1 and the water inlet 33. The reinforcing rod 34 is connected between the bracket 1 and the water inlet 33, and mainly plays the role of enhancing the stability of the pump body structure. During the operation of a high-speed multi-stage centrifugal pump, the pump body is subjected to various forces such as the impact and vibration of the liquid and the inertial force generated by its own high-speed operation. The reinforcing rod transmits these forces in a dispersed manner by rigidly connecting the bracket and the water inlet, effectively enhancing the strength and stability of the overall structure of the pump body, preventing structural deformation and damage caused by uneven force or vibration, ensuring that the relative positions of the components of the pump are stable under long-term high-load operation, and ensuring the normal working performance of the pump.

[0044] MHD stabilization mechanism caused by spatial coupling between Halbach magnetic array and air film shear zone: 1. Structural foundation: The formation of the spatial overlap zone, in this application: an annular Halbach magnetic array is embedded at the upper and lower steps of the rotor, and the magnetic array has the characteristics of magnetic flux concentration and internal and external orientation; corresponding to this, a multi-stage annular conical nozzle is set on the inner wall of the main air cavity inside the pump body, and the nozzle airflow outlet is directly opposite to the outer edge of the rotor end, that is, the location of the magnetic array; thus, when the rotor is in working state, the area where the magnetic flux density changes drastically overlaps with the high-speed shear airflow area. This structural layout forms a physical "multi-field strength coupling zone", and there are: strong gradient changes in magnetic induction intensity (Halbach array characteristics); boundary shear layer (nozzle air film) formed by high-speed gas flow; time-varying magnetic field under high-speed rotation.

[0045] 2. Interaction between magnetic disturbance and fluid shear under high-speed rotation: When the rotor runs at a high speed, the permanent magnets embedded in the rotor rotate at a high speed, forming a rapidly changing alternating magnetic field in the magnetic pole area. Due to the Halbach structure, the magnetic field is highly concentrated on one side (towards the air film direction). When the rotor rotates, the alternating magnetic field generates magnetic disturbances in the air film area formed by the nozzle ejection. The high-speed airflow ejected from the nozzle forms a thin layer of air film (thickness is about 10~50μm) near the rotor surface. The air film is in a shear flow state and has a certain local micro-vortex structure. At this time, the alternating magnetic field penetrates this tiny shear flow area and interacts with the vortex or ion components therein.

[0046] 3. Magnetic field confinement mechanism of micro-vortices Although the conductivity of air itself is extremely low, under the conditions of high-speed shear flow and high local temperature rise, there is extremely weak conductivity in the air film. According to the basic principles of magnetohydrodynamics (MHD), when a conductive fluid moves in a magnetic field, it will induce eddy currents, which in turn generate a magnetic field, interact with the original magnetic field, and generate Lorentz force. For the situation in this device, this effect is mainly manifested as the "restraining" effect of the magnetic field on the micro-vortices, that is: the Lorentz force hinders the expansion and rotation of the conductive vortices, thereby stabilizing the boundary layer flow pattern and slowing down the development of perturbations.

[0047] In other words, although the conductivity in the gas film is weak, the magnetic perturbation is intense enough and highly concentrated in space, and it exerts the effect of a "constraining field" on the vortex perturbations or micro-unstable regions existing in the gas film.

[0048] 4. Results: The mechanism for enhancing the stability of the gas film support The effect of the magnetic field on the gas film perturbation is ultimately manifested as follows: First, at the microscopic level, it inhibits the irregular perturbations or vortex collapses at the gas film boundary, avoiding local decreases in the gas film thickness; second, at the macroscopic level, it can extend the continuity and stability of the gas film, enabling the rotor to be more stably supported by the gas film; a flexible coupling mechanism is formed between the gas film support and the magnetic levitation support. When one party is perturbed and drops, the stability mechanism of the other party starts to take effect, playing an automatic buffering and mutual compensation role.

[0049] The working principle of the present invention can be specifically divided into the following stages: 1. Power transmission and impeller rotation: After the motor 21 in the drive mechanism is started, it drives the coupling 22 to rotate through the output shaft. The coupling 22 then transmits the power to the pump shaft 23. Since the rotor 14 has an interference fit with the pump shaft 23, the pump shaft 23 drives the rotor 14 to rotate together. At the same time, the impeller 32 installed on the pump shaft 23 also rotates with the pump shaft 23. The rotation of the impeller 32 forms a centrifugal force in the pump body 3, throwing the liquid entering from the water inlet 33 towards the outer edge of the impeller 32, realizing the transportation of the liquid.

[0050] 2. Magnetic levitation and damping: The permanent magnet 141 embedded in the rotor 14 interacts with the magnetic poles 16 arranged in a circular Halbach magnetic array inside the bracket 1 to generate a magnetic levitation force, enabling the rotor 14 to levitate and rotate at high speed in the main air cavity 12. When the rotor 14 vibrates due to various factors, the changing magnetic field generated by the permanent magnet 141 will generate eddy currents in the conductive lining 17 on the outer edge of the magnetic pole 16. The magnetic field generated by the eddy currents interacts with the magnetic field of the permanent magnet 141 to generate an eddy current damping force, hindering the vibration of the rotor 14 and improving the system stability by using the magnetic damping effect.

[0051] 3. Gas assistance and pressure division: External gas enters the air passage 19 through the air valve 18 and then enters the pressure division air cavity 11. The gratings 20 arranged in an array at the upper and lower ends of the connection between the pressure division air cavity 11 and the main air cavity 12 enable the gas to evenly enter the main air cavity 12 from the pressure division air cavity 11. The nozzles 13 annularly distributed on the inner edge cavity wall of the main air cavity 12 eject the gas at a specific angle. Since the nozzles 13 have a symmetric conical structure with three gradually shrinking conical sections, the contraction angle of each section is 5°-10°, and there are throttle holes 15 at the end section, which makes the ejected gas form a high-speed air flow, acting on the rotor 14, playing a certain role in supporting and stabilizing the rotor 14, and also helping to cool and lubricate the rotor 14.

[0052] 4. Sealing and protection: The mechanical seal 24 fixed to the outer edge of the pump shaft 23 is clamped between the bracket 1 and the impeller 32 to prevent the liquid in the pump body 3 from leaking. The overflow cavity 111 is used to collect the possibly leaked liquid. The oil seal 25 arranged at the contact between the upper end of the overflow cavity 111 and the pump shaft 23 further prevents the liquid from leaking along the pump shaft 23, playing a role in sealing and protection and ensuring the normal operation of the system.

[0053] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A gas film supported high-speed multi-stage centrifugal pump, comprising a bracket (1), wherein a driving mechanism (2) and a pump body (3) are respectively fixed at the upper and lower ends of the bracket (1), and it is characterized in that, Inside the bracket (1), a pressure-dividing air cavity (11) and a main air cavity (12) are provided. A nozzle (13) is penetrated through the inner edge cavity wall of the main air cavity (12). A rotor (14) is sleeved inside the main air cavity (12). The nozzles (13) are distributed in a ring along the cavity wall of the main air cavity (12). The nozzles (13) are of an overall symmetric conical structure, provided with three gradually shrinking conical sections, and the shrinking angle of each section is 5°-10°. A throttle hole (15) is provided at the end section of the nozzle (13). A permanent magnet (141) is embedded inside the rotor (14). Multiple groups of magnetic poles (16) are embedded inside the bracket (1) and arranged in a ring-shaped Halbach magnetic array. Each group of magnetic poles (16) rotates 90° relative to the previous group. The magnetic poles (16) are arranged at the step positions at the upper and lower ends of the rotor (14). A conductive lining plate (17) is provided at the outer edge of the magnetic poles (16).

2. The high-speed multi-stage centrifugal pump supported by an air film according to claim 1, wherein An air valve (18) and an air duct (19) are provided on the side of the bracket (1). The air duct (19) is connected to the pressure-dividing air cavity (11).

3. The high-speed multi-stage centrifugal pump supported by an air film according to claim 1, wherein, The upper and lower ends of the pressure-dividing air cavity (11) and the main air cavity (12) are arc-shaped. Grilles (20) are arranged in an array at the upper and lower ends of the connection between the pressure-dividing air cavity (11) and the main air cavity (12).

4. A high-speed multi-stage centrifugal pump supported by an air film according to claim 1, characterized in that An overflow cavity (111) is provided at the inner bottom of the bracket (1).

5. A gas film supported high-speed multi-stage centrifugal pump according to claim 1, characterized in that, The driving mechanism (2) includes a motor (21). A coupling (22) is fixed to the end of the output shaft of the motor (21). A pump shaft (23) is fixed to the lower end of the coupling (22).

6. The high-speed multi-stage centrifugal pump supported by an air film according to claim 1, wherein, The rotor (14) is in interference fit with the pump shaft (23).

7. A gas film-supported high-speed multi-stage centrifugal pump according to claim 1, characterized in that, The pump body (3) includes a guide vane (31) fixed to the lower end of the bracket (1) and an impeller (32) installed on the pump shaft (23). An inlet (33) is provided at the bottom of the pump body (3). A strengthening tie rod (34) is provided on the side of the pump body (3).

8. A gas film supported high-speed multi-stage centrifugal pump according to claim 4, characterized in that, An oil seal (25) is provided at the contact position between the upper end of the overflow cavity (111) and the pump shaft (23).

9. A gas film-supported high-speed multi-stage centrifugal pump according to claim 5, characterized in that, A mechanical seal (24) is fixed to the outer edge of the pump shaft (23). The mechanical seal (24) is clamped between the bracket (1) and the impeller (32).

10. A high-speed multi-stage centrifugal pump supported by an air film according to claim 1, characterized in that, An outlet (112) is provided on the side of the bracket (1).

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