A sleeve structure of an extrusion oil film damper for a pump

Abstract

The application relates to a sleeve structure of an extrusion oil film damper for a pump, which comprises a sleeve base body and a damper inner ring, a plurality of first circular-arc grooves are arranged uniformly and at intervals on the inner ring surface of the sleeve base body, and a fan-shaped table surface is formed at the position; a second circular-arc groove is arranged on the table surface, each second circular-arc groove extends to the other end surface of the sleeve base body in the axial direction, so that the first circular-arc groove and the second circular-arc groove are connected in the axial direction and jointly form a lubricating flow channel for the flow of lubricating medium; two sleeve base bodies are symmetrically arranged at the two ends of the damper inner ring, the lubricating flow channels of the two sleeve base bodies are symmetrically arranged, a damper inner ring built-in flow channel is arranged on the side wall of the damper inner ring and is used for supplying lubricating medium to the inside of the damper inner ring. The sleeve structure is optimized in the sleeve structure and the lubricating flow channel design, uniform distribution and continuous supply of the lubricating medium are realized, the overall operation stability and lubricating efficiency of the shafting are improved, and the service life is prolonged.

Description

Technical Field

[0001] This invention belongs to the field of damper and multiphase pump technology, specifically relating to a sleeve structure of a pump extrusion oil film damper. Background Technology

[0002] Multiphase pumps are key equipment used for pressurizing and transporting mixtures of oil, gas, water, and small amounts of solid particles. They are widely used in oil and gas field development, offshore platform gathering and transportation, deep-sea pipeline transportation, chemical process circulation, and remote wellhead pressurization. Compared with conventional water pumps or single-phase centrifugal pumps, the phase, gas content, viscosity, pressure, and sand content of the inlet medium in multiphase pumps often change continuously with well conditions, pipeline back pressure, temperature, and production stage. The flow inside the pump exhibits strong unsteadiness, strong coupling, and wide operating conditions. Multiphase pumps can reduce front-end separation equipment, lower wellhead back pressure, and improve gathering and transportation efficiency. However, their direct transport of gas-liquid mixtures also significantly complicates issues such as pressure pulsation, axial force fluctuations, rotor vibration, and sealing and lubrication problems within the pump.

[0003] During the operation of a multiphase pump, the density difference between the gas and liquid phases is significant, resulting in uneven distribution of the two phases within the impeller, guide vanes, hub, blade tip clearance, and pump chamber. As the inlet gas content increases, the gas phase tends to accumulate in local low-pressure areas, near the hub, or within the diffuser channel, while the liquid phase concentrates towards the outer edge or high-pressure areas under the influence of centrifugal force and pressure gradient. When the gas-liquid distribution undergoes periodic changes, the blade load, channel pressure, and rotor force fluctuate accordingly, potentially inducing radial vibration, axial movement, localized rubbing, and seal leakage risks. Especially under conditions of high gas content, slug flow, low liquid volume, or start-stop switching, the state of the medium within the pump changes rapidly, making it difficult for traditional support and lubrication structures determined by a single design point to maintain a stable operating state.

[0004] To improve the stability of multiphase pump rotor systems, squeeze film dampers are typically installed in bearings or supports during engineering applications. These dampers utilize the relative radial motion between the support ring and the outer sleeve during rotor vibration to periodically squeeze and shear the lubricating medium within the gap. The viscosity of the lubricating medium dissipates mechanical vibration energy, thereby increasing system damping, reducing vibration amplitude at critical speeds, and suppressing oil film eddy and rotor instability. This type of structure is widely used in support systems for high-speed rotating machinery, compressors, turbines, and aero-engines, and is increasingly being applied to vibration reduction designs for complex media transport equipment such as multiphase pumps. The actual vibration reduction effect of a squeeze film damper depends on factors such as oil film thickness, oil supply method, gap size, lubricant viscosity, rotor eccentricity, oil film pressure distribution, and boundary leakage conditions. Among these, the sleeve base, as the core component of the damper that bears the lubricant, forms the squeeze film, and defines the fluid channel, directly influences the oil film pressure buildup and damping force output. The structural morphology of the inner surface of the sleeve base determines the storage, replenishment, discharge, and redistribution of the lubricant in the circumferential and axial directions, and also affects the continuity, stability, and disturbance resistance of the oil film. Therefore, the sleeve base is not merely an ordinary mounting bushing, but a crucial functional component that determines the dynamic performance of the damper.

[0005] For multiphase pump compression film dampers, using ordinary smooth sleeves, simple oil groove sleeves, or single annular groove sleeves will be insufficient to meet the comprehensive requirements for oil film uniformity, damping stability, start-up lubrication, and structural compactness under complex operating conditions. Especially in scenarios with high gas content, multiple pressure pulsations, wide flow ranges, limited space, harsh lubrication environments, complex loads, and significant vibrations, traditional structures are prone to problems such as uneven distribution of lubricating medium, localized oil film rupture, excessively rapid axial leakage, sensitive assembly eccentricity, and accelerated wear during operation, leading to reduced service life. Improvements through external oil supply, self-aligning supports, micro-textures, or complex damping components generally suffer from high processing and maintenance requirements, large structural modifications, or insufficient compatibility with existing pump bodies. Summary of the Invention

[0006] To address at least one of the problems in the prior art, the present invention aims to provide a sleeve structure for a pump extrusion oil film damper. By optimizing the sleeve structure and lubrication channel design, uniform distribution and continuous supply of lubricating medium are achieved, thereby improving the overall operating stability and lubrication efficiency of the shaft system and extending its service life.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A sleeve structure for a pump-use extrusion film damper includes: The sleeve base has several evenly spaced first arc grooves on its inner ring surface. The first arc grooves extend axially from one end face of the sleeve base to a predetermined depth, where they form a fan-shaped platform with the inner ring surface. Second arc grooves are formed on the platform, with the arc radius of the second arc grooves being smaller than that of the first arc grooves. Each second arc groove extends axially to the other end face of the sleeve base, thereby connecting the first arc grooves and the second arc grooves axially to form a lubrication channel for the flow of lubricating medium. The inner ring of the damper has two sleeve bases symmetrically arranged at both ends, which enables the lubrication channels of the two sleeve bases to be symmetrically arranged. The side wall of the inner ring of the damper has an internal flow channel for supplying lubricating medium to the interior of the inner ring of the damper.

[0008] Preferably, the axis of the first arc groove and the axis of the second arc groove in each of the lubrication channels are coplanar with the central axis of the sleeve base.

[0009] Preferably, the axial length of the first arc groove accounts for three-quarters of the total length of the sleeve base, and the axial length of the second arc groove accounts for one-quarter of the total length of the sleeve base.

[0010] Preferably, the radius of the cross-section of the second arc groove is one-sixth of the radius of the cross-section of the first arc groove.

[0011] Preferably, the number of the first arc groove and the number of the second arc groove are equal, and there are four of each.

[0012] Preferably, the number of lubrication channels in the sleeve base is even, and they are arranged in pairs at radially opposite positions.

[0013] Preferably, the first arc groove and the outer surface of the pump shaft enclose a first cavity region, the second arc groove and the outer surface of the pump shaft enclose a second cavity region, and the first cavity region and the second cavity region are connected to form the composite lubrication cavity of the lubrication channel.

[0014] Preferably, the platform is located between the first arc groove and the second arc groove, and is perpendicular to the axis of the first arc groove and the axis of the second arc groove. The platform is used to form a transition area when the lubricating medium flows from the first arc groove to the second arc groove.

[0015] Preferably, a gap is provided between the inner ring of the damper and the pump shaft, which can communicate with the first arc groove of the two sleeve bases along the axial direction, so that the lubricating medium can flow to the lubrication channels of the two sleeve bases.

[0016] Preferably, the sleeve base is bolted to the inner ring of the damper, and the two sleeve bases are symmetrically mounted on the inner ring of the damper.

[0017] The present invention has the following advantages due to the adoption of the above technical solutions: 1. The sleeve structure of the pump extrusion oil film damper provided by the present invention, by setting an interconnected first arc groove and a second arc groove and symmetrically arranging the sleeve base at both ends of the inner ring of the damper, constructs a continuous and uniform lubrication flow channel, ensuring that the lubricating medium can be replenished to the lubrication area in a timely manner during operation. Even in the case of high gas content or uneven medium, the oil film can be quickly rebuilt, preventing metal contact and avoiding shaft vibration and wear caused by uneven lubrication.

[0018] 2. The sleeve structure of the pump extrusion oil film damper provided by this invention has a compact overall structure, making it particularly suitable for challenging multiphase flow conditions such as deep-sea oil and gas mixed transportation. It exhibits high adaptability and reliability. The arc groove structure is rationally designed, reducing the overall amount of lubricating medium used while achieving uniform distribution of the lubricating medium in the circumferential direction, thus improving lubrication effect and system economy. The lubricating medium enters from the built-in flow channel in the inner ring of the damper. As it flows from the first arc groove side to the second arc groove side, the cross-sectional area of ​​the flow channel gradually decreases, forming a certain pressure gradient. This helps to quickly establish a dynamic pressure oil film during the start-up phase, effectively avoiding dry friction and improving start-up performance and operational reliability. While ensuring lubrication effect, this structure also has the advantages of simple structure, convenient processing, and easy installation and maintenance. It is suitable for various working conditions and has good engineering applicability and promotion value. Attached Figure Description

[0019] Figure 1 This is an overall schematic diagram of the sleeve structure of the pump extrusion oil film damper provided in Embodiment 1 of the present invention.

[0020] Figure 2 This is a three-dimensional schematic diagram of the sleeve base provided in Embodiment 1 of the present invention.

[0021] Figure 3 This is a longitudinal sectional view of the sleeve base provided in Embodiment 1 of the present invention.

[0022] Marked in the attached diagram: 1. Sleeve base; 2. Cylindrical hole; 3. Inner ring surface; 4. First arc groove; 5. Platform; 6. Second arc groove; 7. Damper inner ring; 8. Damper inner ring built-in flow channel. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0024] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the system 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.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "assembly," "setup," and "connection" 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.

[0026] This invention provides a sleeve structure for a pump extrusion oil film damper. By optimizing the sleeve structure and lubrication flow channel design, it achieves uniform distribution and continuous supply of lubricating medium, improves the overall operating stability and lubrication efficiency of the shaft system, and extends its service life.

[0027] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0028] Example 1 Existing multiphase pump rotor systems typically consist of a pump shaft, impeller, guide vanes, balancing components, bearings, seals, and damping support structures. These components are coupled both mechanically and fluidly. During high-speed rotation, the pump shaft is affected not only by unbalanced forces, installation eccentricity, and bearing support stiffness, but also by impeller outlet pressure pulsations, guide vane dynamic-static interference, fluid forces in the sealing gaps, and the non-uniform distribution of the multiphase medium. For long-shaft or high-speed pump units, even small external disturbances can be amplified when the rotor passes through the critical speed or approaches the subsynchronous vibration range. Insufficient damping will widen the shaft trajectory, reduce oil film carrying capacity, and ultimately lead to excessive vibration, accelerated wear, and shortened service life.

[0029] In existing technologies, smooth inner hole sleeves, simple axial oil groove sleeves, annular groove sleeves, or oil supply hole sleeves are commonly used in extrusion oil film dampers or sliding support sleeves. These structures are easy to manufacture, have clear assembly relationships, and can form a basic oil film under conventional single-phase lubrication conditions. However, for equipment such as multiphase pumps, which experience large fluctuations in operating conditions, complex vibration excitation, and limited installation space, the aforementioned traditional sleeve structures still have significant shortcomings: their internal components typically lack a composite flow channel that addresses the combined needs of oil storage, oil guiding, throttling, and pressure equalization. Uneven replenishment of the lubricating medium is prone to occur circumferentially, while excessively rapid leakage may occur axially, leading to insufficient local oil film pressure or unstable pressure distribution.

[0030] Specifically, when the inner bore of the sleeve is a smooth cylindrical surface, the lubricating medium mainly relies on the oil supply pressure, rotor rotation drag, and fluid shear within the gap to form an oil film. When the rotor is eccentric or vibrates significantly, the pressure in areas with smaller gaps will rise rapidly, while areas with larger gaps are prone to low-pressure zones. Without a suitable oil reservoir and flow channel, the lubricating medium cannot be replenished to low-pressure or lean-oil areas in a timely manner, resulting in a locally intermittent oil film. For multiphase pumps, fluctuations in operating conditions, gas-liquid pressure pulsations, and changes in lubrication conditions also affect the damper's oil supply stability and oil film pressure distribution, further reducing the oil film carrying capacity within the smooth sleeve.

[0031] Traditional sleeves employ simple axial grooves or straight-through oil grooves. While these improve the oil supply channel, the groove design is typically limited, making it difficult to simultaneously address multiple needs such as oil storage, throttling, pressure equalization, and prevention of excessive leakage. Excessively wide or highly permeable oil grooves reduce the local bearing area, making it difficult to maintain oil film pressure; conversely, excessively narrow or insufficient grooves result in inadequate oil supply, failing to replenish lubricating medium in a timely manner under high-speed or high-vibration conditions. If the oil groove only extends from one end to the other, the lubricating medium can easily be discharged rapidly along the axial direction, resulting in a short residence time of the oil film within the effective damping zone, making it difficult to form a stable extrusion oil film pressure field.

[0032] Meanwhile, traditional sleeve structures are highly sensitive to assembly precision and coaxiality. Temperature rise, casing deformation, axial thrust fluctuations, bearing wear, and installation errors in the multiphase pump operating environment can all cause relative eccentricity between the sleeve and the pump shaft. Eccentricity leads to a non-uniform distribution of the annular gap; the side with the smaller gap is prone to enhanced oil film shear, increased temperature rise, and even localized rubbing, while the side with the larger gap suffers from insufficient oil film pressure. If the inner surface of the sleeve lacks a structure capable of buffering and redistributing the lubricating medium, the uneven oil film caused by eccentricity will further amplify rotor vibration, creating a vicious cycle of mutually reinforcing vibration, wear, and gap changes.

[0033] The wide operating conditions of multiphase pumps place higher demands on the squeeze film damper. Inlet gas content, pressure pulsation, start-stop switching, and flow fluctuations cause continuous changes in rotor load and support conditions, thus affecting the establishment and maintenance of the oil film in the damper clearance. If local temperature rise is high or oil supply stability is insufficient, the damper may enter a mixed lubrication or short-term boundary lubrication state. For the squeeze film damper to function effectively in such complex environments, it cannot rely solely on a passive annular clearance; instead, it needs to utilize the internal structure of the sleeve base to ensure that the lubricating medium is distributed as evenly, continuously, and controllably as possible within the load-bearing area, reducing performance degradation caused by lean oil, pressure fluctuations, and excessively rapid oil leakage.

[0034] To address the problems of uneven oil film distribution and insufficient lubrication, various improvement approaches have been proposed in existing technologies. The first approach involves fabricating microtextures on the inner surface of the friction pair or sleeve, such as micro-pits, micro-grooves, corrugated surfaces, or regular textured structures. These microtextures can, to some extent, form micro-oil reservoirs, altering the local fluid shear state and providing lubrication supplementation under boundary lubrication or mixed lubrication conditions. By rationally designing the depth, density, and arrangement of the microtextures, the coefficient of friction can be reduced, the local oil film pressure distribution improved, and wear mitigated during startup or low-speed operation.

[0035] However, microtexturing technology is more suitable for improving surface tribological properties. Its effective scale is usually small, making it difficult to independently handle the large-scale oil film supply and pressure regulation tasks in multiphase pump extrusion film dampers. If microtexturing is machined over a large area inside the sleeve bore, high requirements are placed on machining consistency, cleanliness, and wear resistance. When the lubricating medium contains impurities or contaminants, the micro-pits may be blocked, reducing the actual oil storage and flow guiding effects. More importantly, microtexturing usually cannot form a clear axial composite flow channel, and it is difficult to adjust the overall oil supply and drainage relationship at both ends of the sleeve. Therefore, its improvement on the macroscopic hydrodynamic performance of the damper is limited.

[0036] The second approach compensates for assembly errors by modifying the sleeve support or mounting structure, such as using self-aligning sleeve seats, self-adaptive support rings, elastic support components, or locally flexible connection structures. These solutions can improve shaft alignment to a certain extent, reduce edge loads and the risk of localized contact, and make the oil film more evenly stressed. For equipment with large assembly errors, self-aligning structures can reduce the adverse effects of initial eccentricity, helping to extend the service life of sleeves and bearings.

[0037] However, self-aligning or flexible support solutions primarily address installation and stress posture issues, but cannot fundamentally alter the flow state of the lubricating medium on the inner surface of the sleeve. If the sleeve itself still uses a smooth inner bore or simple oil groove, even with improved neutrality, insufficient oil film replenishment and excessively rapid leakage may still occur under conditions of high gas content, pressure pulsation, or sudden vibration. Furthermore, self-aligning mechanisms often require additional installation space and more parts, increasing structural complexity, assembly procedures, and maintenance difficulty. For established multiphase pump dampers, significant modifications to the external support structure may also be limited by pump body space and installation references.

[0038] The third approach involves optimizing the oil supply, throttling, and return systems. This is achieved through external oil supply pressure, throttling orifices, oil reservoirs, injection holes, or circulating oil circuits to improve lubricant management. This type of solution enhances the controllability of lubricant entry into the damper, prevents localized cavitation or insufficient oil supply during high-speed operation, and slows down excessive lubricant leakage through throttling structures. In some high-speed rotating equipment, specially designed oil supply systems and throttling structures can improve oil film stability and enhance the damper's dynamic performance at different speeds.

[0039] However, external oil supply and complex oil circuits typically mean more piping, sealing interfaces, throttling elements, and monitoring components, increasing system complexity. For multiphase pumps with limited space, especially on offshore platforms, skid-mounted equipment, or deep-sea gathering and transportation systems, additional oil circuits increase layout difficulty and leakage risk. If the lubrication system relies on high oil supply pressure or a precision control unit, damper performance will significantly degrade if the oil supply pressure fluctuates, the oil becomes contaminated, or the throttling orifice becomes blocked. Furthermore, external oil circuits primarily increase lubrication supply at the system level; if the sleeve base lacks proper flow channels, the lubricating medium may not be evenly distributed within the load-bearing area after entering the damper.

[0040] The fourth approach involves employing more complex damping or composite support structures, such as tilting pad bearings, hydrostatic bearings, elastic ring dampers, bellows damping structures, or external active control devices. These solutions can improve rotor stability in terms of support stiffness, damping output, or control force adjustment, and have a certain application basis in large, high-speed machinery. However, such structures typically require high manufacturing precision, installation space, and sophisticated oil supply and control systems, resulting in significant modification costs. For the sleeve base in multiphase pump dampers, adding complex external components to achieve vibration reduction not only alters the original structural dimensions but may also affect the internal flow channels, axial assembly relationships, and ease of maintenance within the pump body.

[0041] Therefore, while existing improvement technologies can improve surface lubrication, assembly alignment, oil supply management, or support damping, most of them address the external system or surface microstructure of the sleeve, lacking a compact solution that can form a stable lubrication medium channel within the sleeve substrate itself. For established or space-constrained multiphase pump dampers, a more practical engineering approach would be to directly improve the flow path, storage capacity, and pressure build-up process of the lubrication medium in the axial and circumferential directions by optimizing the inner ring structure of the sleeve substrate, without significantly increasing external parts or altering the overall size of the damper.

[0042] From a fluid dynamics perspective, a well-designed flow channel on the inner surface of the sleeve should simultaneously possess the functions of oil storage, oil guiding, throttling, and pressure equalization. The oil storage function maintains a reserve of lubricating medium during startup, low-speed, high-gas-content, or pressure-fluctuating phases, preventing dry friction or boundary friction between the rotor and the sleeve. The oil guiding function directs the lubricating medium to the areas that need to bear the load and form an oil film, improving circumferential distribution uniformity. The throttling function controls the axial loss rate of the lubricating medium, ensuring the oil film maintains sufficient residence time within the effective working area. The pressure equalization function reduces local high-pressure and low-pressure differences, minimizing the adverse effects of sudden changes in oil film force on the rotor system.

[0043] Traditional single-size channels often fail to meet the above requirements simultaneously. Larger channels increase oil storage capacity but reduce the bearing area and widen the leakage path; smaller channels offer better throttling but insufficient oil supply, failing to quickly replenish the lubricating medium. If the channels are completely continuous with uniform cross-section along the axial direction, the lubricating medium is prone to rapid unidirectional loss; if channels are only partially installed, dead zones in the oil supply may occur. Therefore, in multiphase pump extrusion film dampers, a composite channel structure with varying cross-sectional dimensions, interconnected axially, and uniformly arranged circumferentially is needed. This allows the lubricating medium to be stored and buffered in a larger volume area before being guided and constrained by smaller channels, thus achieving both oil storage and pressure stabilization.

[0044] From the perspective of channel morphology, circular arc grooves, compared to sharp-corner or rectangular grooves, offer smoother transitions and better surface continuity, reducing local stress concentrations and abrupt flow changes at sharp corners. They also facilitate obtaining stable surface quality using conventional tools or forming processes. The cavity formed between the circular arc groove and the outer circle of the pump shaft can serve as a storage and flow area for the lubricating medium. If a larger circular arc groove is axially connected to a smaller one, it is possible to form a composite channel transitioning from a large to a small volume area. This gradually constrains the lubricating medium during flow, providing a more suitable channel foundation for establishing oil film pressure.

[0045] For compression film dampers, the circumferential distribution of the channels is equally important. If the number or location of the channels is uneven, the circumferential supply and pressure distribution of the lubricating medium will deviate, and the oil film force on the rotor may also have a significant directionality. By uniformly arranging multiple channels circumferentially within the inner ring of the sleeve base, lubricating medium storage and supply capabilities can be achieved at different angular positions. When the rotor experiences radial vibration or changes in its shaft trajectory, oil film support conditions can be obtained in each direction in a timely manner. The circumferentially distributed structure also reduces localized wear caused by insufficient oil supply on one side and promotes a more balanced damping force in the circumferential direction.

[0046] In the axial direction, if a large arc groove is provided at one end of the sleeve base and extends to a certain depth, and then a smaller arc groove is provided on the formed platform and continues to extend to the other end, a segmented composite flow channel can be formed. The larger arc groove can serve as the main oil reservoir and initial oil supply chamber, with a strong capacity to accommodate lubricating media; the platform area can act as a transition, support, and throttling boundary; the smaller arc groove can serve as a flow guide and pressure stabilizing channel, controlling the continued axial flow of the lubricating media. Compared with a simple straight-through groove, this structural approach helps to prevent the lubricating media from rapidly leaking out as soon as it enters the sleeve gap, making it easier to maintain a continuous oil film between the sleeve and the pump shaft.

[0047] Furthermore, the fit between the sleeve base and the inner ring of the damper also affects the distribution of the lubricating medium on both sides of the axial direction. If the sleeve structure can be axially symmetrically embedded and the main oil reservoirs are arranged in a relatively opposite manner, the lubricating medium will more easily remain and be distributed in the gap between the pump shaft and the sleeve after entering the damper. The relatively arranged oil reservoirs can form a more balanced lubricating medium accommodating space on both sides of the axial direction, reducing oil film bias caused by unilateral oil supply or unilateral oil discharge. For multiphase pumps that are significantly affected by axial force fluctuations, the symmetrical structure also helps to maintain the consistency of the fluid state on both sides of the damper, reducing additional disturbances caused by uneven axial pressure.

[0048] From a manufacturing and maintenance perspective, forming an oil storage and flow guiding structure within the inner ring of the sleeve base is more compact than adding complex external dampers, self-aligning mechanisms, or active control actuators. This type of solution primarily improves lubrication medium management by altering the geometry of the sleeve's inner surface, without significantly increasing the damper's outer diameter or axial length, or introducing excessive external piping. For existing multiphase pumps or compact pump sets, the structure centered on optimized internal flow channels is easier to match with the existing damper inner ring, pump shaft, and installation space, providing a better foundation for engineering compatibility.

[0049] Meanwhile, the built-in composite flow channel in the sleeve also helps improve the utilization efficiency of the lubricating medium. Traditional large-channel oil supply schemes often compensate for localized oil shortages by increasing the oil supply volume, but excessive oil supply increases leakage, churning losses, and the burden on the lubrication system. If the inner ring of the sleeve forms a reasonable composite cavity, the lubricating medium can be stored, buffered, and redistributed at the required locations, thereby maintaining an effective oil film with a smaller amount of lubricating medium used. For scenarios with high maintenance costs, such as offshore platforms or deep-sea transportation, reducing lubricating medium consumption and the burden on auxiliary systems has significant engineering implications.

[0050] During the startup phase, the pump shaft has not yet established stable rotational dynamic pressure, and traditional sleeves are prone to boundary lubrication or mixed lubrication, resulting in significant startup friction and initial wear. If the inner ring of the sleeve has a large oil reservoir, the lubricating medium can be pre-reserved within the groove and quickly enter the contact area between the shaft and sleeve when the shaft begins to move, reducing the risk of dry friction. As the rotational speed increases, the smaller guide area continues to guide the lubricating medium axially and forms a constraint, which helps the oil film gradually establish. Therefore, the rationality of the internal flow channels of the sleeve directly affects the lubrication continuity of the damper from startup to stable operation.

[0051] During stable operation, rotor vibration causes periodic compression and release of the lubricating medium within the sleeve clearance. The oil reservoir and flow guide provided by the composite channels can buffer pressure surges during compression and replenish lubricating medium during release, reducing oil film rupture. Larger channels are beneficial for providing sufficient medium reserves, while smaller channels are beneficial for limiting flow and maintaining pressure; the combination of both can improve the stability of the oil film pressure field. For operating conditions with significant changes in gas content or pressure pulsations, this structural approach can, to some extent, mitigate the impact of lubricating medium supply fluctuations on damping performance.

[0052] During vibration, shock, or abnormal disturbance phases, the rotor may temporarily deviate from its center position, causing a sharp reduction in local clearances. Traditional smooth sleeves are prone to creating localized high pressure and high shear at this time, and insufficient lubrication medium replenishment may lead to rubbing. Channels with interconnected oil storage and guidance functions provide additional flow space and pressure buffer space for the lubricating medium, allowing for a redistribution path for the medium in localized high-pressure areas while ensuring replenishment in low-pressure areas. Although this type of structure cannot eliminate all vibration sources, it improves the oil film's adaptability to transient eccentricity and periodic compression.

[0053] From a thermal stability perspective, the squeeze film damper generates heat during long-term operation due to lubricant shear, rotor vibration energy consumption, and localized friction. If the flow path of the lubricant within the sleeve is unreasonable, heat can easily concentrate in localized high-shear areas, leading to a decrease in lubricant viscosity, reduced oil film carrying capacity, and further temperature rise and wear. For multiphase pumps, the temperature, pressure, and operating conditions of the medium within the pump already fluctuate, making it even more difficult to maintain a stable thermal state for the lubricant. A well-designed composite channel, by providing a certain volume of oil storage space and a continuous flow path, allows the lubricant to undergo more thorough exchange and renewal within the sleeve, helping to reduce the adverse effects of localized heat accumulation on oil film performance.

[0054] From the perspective of impurities and on-site operation, the medium transported by multiphase pumps may contain fine sand particles, corrosion products, or pipeline impurities. Although squeeze film dampers usually have relatively independent lubrication media, it is still difficult to completely avoid contaminants entering the lubrication system during long-term operation. Traditional micro-channel or sharp-angled groove structures are at risk of clogging and deposition under contaminated conditions. Once a local channel is blocked, the uniformity of oil supply will rapidly decrease. Compared to isolated micropores or complex fine meshes, smooth-profiled, continuously arranged channel structures are generally easier to manufacture, clean, and maintain.

[0055] From a manufacturing consistency perspective, pump damper sleeves typically require guaranteed internal bore dimensional accuracy, roundness, coaxiality, and surface quality. Designing overly complex three-dimensional flow channels or numerous micro-scale structures within the sleeve's inner ring significantly increases machining difficulty and inspection costs, and may also affect oil film formation due to residual burrs, stress concentration at sharp corners, or dimensional deviations. Structures like circular arc grooves can be achieved through milling, boring, forming tools, or CNC machining, resulting in smooth transitions between the groove bottom and edges, facilitating dimensional repeatability control. For components requiring mass production for pump units, controllable machining and consistent quality are crucial conditions for the successful engineering implementation of such structures.

[0056] From a structural strength perspective, the sleeve base in the damper serves multiple functions: creating lubrication gaps, positioning, supporting, and transmitting loads. Excessively weakening the inner ring material to increase oil storage capacity may reduce the sleeve base's stiffness, affecting its fit stability with the damper's inner ring. Similarly, overly concentrated channel arrangement may cause localized stress concentration. Therefore, the sleeve's internal flow channels need to maintain necessary support surfaces while creating space for lubricating medium flow, ensuring the inner ring of the sleeve has both medium flow conditions and a certain continuous load-bearing area, thus achieving a balance between lubrication performance and structural strength.

[0057] From the perspective of damper integration with the pump body, the internal space of a multiphase pump is typically occupied by the impeller, guide vanes, bearings, seals, balancing components, and casing flow channels, leaving limited space for adding new vibration damping components. Adding an independent oil chamber, external accumulator, or additional support components to improve damping performance may alter the original axial dimensions and assembly sequence, and even affect pump body strength and maintenance access. Centralizing the function to the inner ring groove of the sleeve base allows for lubrication medium management and improved oil film stability using the existing sleeve mounting location, eliminating the need to transfer the problem to external auxiliary systems. This intrinsic structural improvement better meets the engineering requirements of compact multiphase pumps.

[0058] From a failure mode perspective, common problems with traditional sleeve structures under complex operating conditions include insufficient oil film pressure, localized dry friction, abnormal temperature rise, journal wear, scoring on the inner surface of the sleeve, and increased subsynchronous components in the vibration spectrum. These phenomena are often not caused by a single factor, but are the result of the combined effects of insufficient lubrication, pressure pulsation, rotor eccentricity, and thermal deformation. If the sleeve lacks a structure capable of buffering and regulating the lubricating medium, disturbances from any one factor can be amplified along the chain of decreasing oil film carrying capacity. By constructing channels with oil storage and throttling capabilities, a certain buffer margin can be provided for the aforementioned disturbances, reducing the probability of the failure developing from initial lubrication abnormalities to severe wear or excessive vibration.

[0059] From the perspective of current technological development, existing improvements to damper sleeves focus more on materials, installation methods, external oil supply, or single-channel arrangements. However, there are still shortcomings in the dedicated built-in composite flow channel structure for pump-use extrusion film dampers operating in a wide range of multiphase pump environments. In particular, how to design channels within the limited wall thickness of the sleeve that can both store and guide oil, maintain the bearing platform while reducing oil discharge velocity, and are both easy to manufacture and symmetrically assembled with the inner ring of the damper, is a problem that current technology has not fully solved. Therefore, structural improvements to the composite arc groove on the inner surface of the sleeve base and its axial connectivity are specifically targeted.

[0060] Existing technologies include solutions for incorporating oil holes, oil grooves, or annular grooves on bearings or sleeves. However, many designs only focus on the oil inlet or simple connection, failing to systematically address the oil storage, throttling, and symmetrical arrangement requirements of multiphase pump extrusion film dampers. Simple annular grooves may weaken the continuity of the load-bearing area, straight axial grooves may cause excessively rapid oil leakage, and isolated oil holes are prone to localized oil supply concentration and insufficient circumferential distribution. Therefore, for pump extrusion film dampers, a sleeve structure that can form clearly defined functional zones within a sleeve base and simultaneously accommodate lubricant storage, flow guidance, and pressure maintenance is still needed.

[0061] This embodiment provides a sleeve structure for a pump-use extrusion oil film damper, which can improve the distribution of lubricating medium, extend the oil film residence time, improve the circumferential supply uniformity, and take into account the feasibility of processing within a limited space. This structure forms a built-in composite flow channel in the inner ring of the sleeve base, which has the functions of oil storage, flow guidance, throttling, and pressure stabilization. Through circumferential uniform distribution and axial symmetrical matching, it improves the utilization efficiency of the lubricating medium and the operating stability of the damper. Thus, without significantly increasing external components and installation space, it improves the oil film support and vibration reduction conditions of a multiphase pump rotor system. Please refer to Figures 1 to 3 This embodiment provides a sleeve structure for a pump-use extrusion film damper, comprising a sleeve base 1 and a damper inner ring 7. The sleeve base 1 is installed inside the inner ring of the pump's squeeze film damper to support the pump shaft. Its core feature is the optimized lubrication channel layout inside the base to improve the distribution and supply of the lubricating medium.

[0062] Two sleeve bases are symmetrically arranged at both ends of the inner ring 7 of the damper, which enables the lubrication channels of the two sleeve bases 1 to be symmetrically arranged. The inner wall of the inner ring 7 of the damper is provided with an inner ring internal flow channel 8 for supplying lubricating medium to the interior of the inner ring 7 of the damper.

[0063] The sleeve base 1 is an annular disc structure, symmetrically embedded axially into the inner ring 7 of the damper. Several cylindrical holes 2 are evenly spaced along the circumference of the ends of the sleeve base 1, and corresponding threaded holes are machined into the inner ring 7 of the damper. The sleeve base 1 and the inner ring 7 of the damper are connected by bolts, with the two sleeve bases symmetrically mounted on the inner ring of the damper. Specifically, these cylindrical holes 2 are used to pass bolts through, fixing the sleeve base 1 to the inner ring 7 of the damper, ensuring the structural rigidity and positioning accuracy of the entire damper during operation.

[0064] The inner ring surface 3 of the sleeve base 1 is provided with several evenly spaced first arc grooves 4. The first arc grooves 4 extend axially from one end face of the sleeve base 1 to a set depth position, and form a fan-shaped platform 5 with the inner ring surface 3 at that position. Second arc grooves 6 are formed on the platform 5. The radius of the second arc grooves 6 is smaller than the radius of the first arc grooves 4. Each second arc groove 6 extends axially to the other end face of the sleeve base 1, thereby connecting the first arc grooves 4 and the second arc grooves 6 axially, forming a lubrication channel for the flow of lubricating medium. Compared with traditional smooth sleeves, single uniform cross-section axial grooves, and ordinary through oil grooves, this structure utilizes first and second arc grooves with different arc radii connected in series axially to form a variable cross-section composite lubrication channel with clear functional zones within the sleeve base 1. The first arc groove 4 with a larger cross-section undertakes the functions of liquid storage, liquid replenishment, and pressure buffering, while the second arc groove 6 with a smaller cross-section undertakes the functions of flow guidance, throttling, and limiting axial leakage. Thus, without increasing external oil supply components and installation space, it takes into account the continuous supply of lubricating medium, the maintenance of oil film pressure, and the load-bearing capacity of the sleeve.

[0065] In this embodiment, the sleeve structure of the pump extrusion oil film damper has a lubrication channel that is a co-directional, segmented composite channel consisting of a "long volume oil storage section + a short cross-section throttling section" within a limited axial space. Combined with the mirror arrangement of the two sleeve bases 1, the lubricating medium enters from the middle of the damper, is first stored and buffered, and then discharged in a controlled manner. This simultaneously solves the problems of discontinuous oil supply, excessively rapid axial leakage, difficulty in maintaining oil film pressure, and uneven circumferential oil film force.

[0066] In this embodiment, the axes of the first and second arc grooves in each lubrication channel are coplanar with the central axis of the sleeve base. The first arc groove 4 and the second arc groove 6 are directly opposite each other in the same radial direction, so that the lubricating medium does not need to undergo circumferential deflection when entering the second arc groove 6 from the first arc groove 4, which can reduce flow separation, eddies, and local pressure loss at the interface. Combined with the circumferentially symmetrical arrangement of multiple lubrication channels, it can also improve the consistency of oil supply and oil film pressure distribution in all directions, and reduce the additional disturbance to the pump shaft caused by asymmetrical oil film force. The axial length of the first arc groove accounts for three-quarters of the total length of the sleeve base, and the axial length of the second arc groove accounts for one-quarter of the total length of the sleeve base. The first arc groove 4, occupying three-quarters of the total length, provides a large oil storage and pressure buffer space, ensuring a continuous supply of lubricating medium to most of the axial working area. The second arc groove 6, occupying one-quarter of the total length, is located on the outlet side and forms a concentrated throttling effect with a shorter cross-section channel, suppressing excessively rapid axial leakage of the lubricating medium. Limiting the second arc groove 6 to one-quarter of the total length avoids excessive flow resistance and slow oil replenishment caused by using small cross-sections throughout the flow channel. Therefore, this ratio balances oil storage capacity, oil replenishment speed, axial leakage control, and oil film pressure maintenance. The radius of the arc of the second arc groove 6 is one-sixth that of the first arc groove 4, causing a significant cross-sectional contraction at the junction of the two grooves. This significantly increases the flow resistance of the second arc groove section, concentrating the main pressure drop in the short groove section near the outlet. This suppresses leakage, prolongs the residence time of the lubricating medium in the first arc groove, and maintains the pressure in the first arc groove and its adjacent oil film area.

[0067] Specifically, the number of lubrication channels within the sleeve base is even, and they are arranged in pairs at radially opposite positions. The number of the first and second circular arc grooves is equal, and there are four of each.

[0068] Each first arc groove 4 starts from one end face of the sleeve base 1 and extends axially inward to a predetermined depth, but does not penetrate to the other end. A fan-shaped stepped surface, i.e., a platform 5, is formed between the bottom of the first arc groove 4 and the original inner ring surface 3 of the sleeve base 1. A second arc groove 6 is further machined on each platform 5. The second arc groove 6 starts from the platform 5 and continues axially until it penetrates to the other end face of the sleeve base 1. Both the first arc groove 4 and the second arc groove 6 are evenly distributed circumferentially around the central axis of the sleeve base. Furthermore, the axes of each first arc groove 4 and its corresponding second arc groove 6 in the circumferential direction are located in the same radial plane, i.e., the axes of the pair of grooves are coplanar with the central axis of the sleeve base.

[0069] In this embodiment, the first arc groove 4 and the outer surface of the pump shaft enclose a first cavity region, and the second arc groove 6 and the outer surface of the pump shaft enclose a second cavity region. The first cavity region and the second cavity region are connected to form a composite lubrication cavity for the lubrication flow channel. The platform 5 is located between the first arc groove 4 and the second arc groove 6, and is perpendicular to the axis of the first arc groove 4 and the axis of the second arc groove 6. The platform 5 is used to form a transition area when the lubricating medium flows from the first arc groove to the second arc groove. A gap is provided between the inner ring 7 of the damper and the pump shaft to maintain vertical communication, allowing the lubricating medium to flow to the lubrication flow channels of the two sleeve bases 1.

[0070] In practical applications, when the pump shaft is installed in the inner hole of the sleeve base 1, the outer surface of the pump shaft and the concave surface of the first arc groove 4 together form a first cavity region. Simultaneously, the outer surface of the shaft and the concave surface of the second arc groove 6 together form a second cavity region. Since the first and second arc grooves are axially connected, the first and second cavity regions together constitute a continuous, open-end composite cavity system. Before and during operation of the sleeve base 1, this composite cavity system will be filled with lubricating medium.

[0071] When the sleeve base 1 is symmetrically and axially embedded in the inner ring 7 of the damper, the first arc grooves on the two sleeve bases 1 at both ends are arranged "face to face". This allows the lubricating medium to remain in the gap between the pump shaft and the sleeve base 1 as much as possible after entering from the built-in flow channel 8 of the inner ring of the damper. This symmetrical arrangement design ensures the efficient utilization of the lubricating medium.

[0072] The working principle of the sleeve structure of the pump extrusion oil film damper in this embodiment is as follows: During pump shaft operation, the lubricating medium enters through the built-in flow channel 8 within the inner ring of the damper, flows from the first cavity region where the first arc groove 4 is located, through the transition zone at the platform 5, and into the second cavity region where the second arc groove 6 is located. As the flow cross-sectional area gradually decreases from the first arc groove to the second arc groove, the lubricating medium is constrained and generates initial pressure during flow. This pressure helps form a preliminary lubricating film between the pump shaft and the sleeve base 1, slightly lifting the shaft, thereby effectively avoiding dry friction or boundary friction during the startup phase and significantly reducing starting torque and wear.

[0073] Once the shaft system enters normal operating condition, as the rotational speed increases, the pump shaft's rotation drives the lubricating medium to continuously flow, replenish, and discharge within the composite cavity formed by the first and second arc grooves. The first arc groove 4 serves as the main oil storage and supply cavity, promptly replenishing the lubricating medium to the friction pairs; the second arc groove 6 guides the flow and establishes a stable dynamic pressure oil film. This design ensures a uniform and continuous supply of lubricating medium along the circumference of the pump shaft, overcoming the problems of uneven lubrication or localized oil shortages that may occur in traditional structures. Simultaneously, because the flow channel is a pre-designed regular cavity, the amount of lubricating medium used is precisely controlled, achieving both excellent lubrication performance and economy.

[0074] In summary, this embodiment innovatively designs interconnected first and second arc grooves with varying cross-sections within the inner ring of the sleeve base 1, constructing a highly efficient and stable built-in lubrication system. This system not only provides excellent starting performance and prevents dry friction, but also ensures uniform and continuous lubrication during operation, perfectly matching the complex dynamics and multiphase flow environment of multiphase pumps. While providing reliable support, it significantly improves the robustness and durability of the lubrication system, providing a key foundational component guarantee for the long-term safe operation of high-end multiphase mixing and conveying equipment.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A sleeve structure for a pump-use extrusion film damper, characterized in that, include: The sleeve base has several evenly spaced first arc grooves on its inner ring surface. The first arc grooves extend axially from one end face of the sleeve base to a predetermined depth, where they form a fan-shaped platform with the inner ring surface. Second arc grooves are formed on the platform, with the arc radius of the second arc grooves being smaller than that of the first arc grooves. Each second arc groove extends axially to the other end face of the sleeve base, thereby connecting the first arc grooves and the second arc grooves axially to form a lubrication channel for the flow of lubricating medium. The inner ring of the damper has two sleeve bases symmetrically arranged at both ends, which enables the lubrication channels of the two sleeve bases to be symmetrically arranged. The side wall of the inner ring of the damper has an internal flow channel for supplying lubricating medium to the interior of the inner ring of the damper.

2. The sleeve structure of the pump extrusion oil film damper according to claim 1, characterized in that, The axis of the first arc groove and the axis of the second arc groove in each of the lubrication channels are coplanar with the central axis of the sleeve base.

3. The sleeve structure of the pump extrusion oil film damper according to claim 1, characterized in that, The axial length of the first arc groove accounts for three-quarters of the total length of the sleeve base, and the axial length of the second arc groove accounts for one-quarter of the total length of the sleeve base.

4. The sleeve structure of the pump extrusion oil film damper according to claim 1, characterized in that, The radius of the cross-section of the second circular arc groove is one-sixth of the radius of the cross-section of the first circular arc groove.

5. The sleeve structure of the pump extrusion oil film damper according to claim 1, characterized in that, The number of the first arc groove and the second arc groove are equal, and there are four of each.

6. The sleeve structure of the pump extrusion oil film damper according to claim 1, characterized in that, The number of lubrication channels in the sleeve base is even, and they are arranged in pairs at radially opposite positions.

7. The sleeve structure of the pump extrusion oil film damper according to claim 1, characterized in that, The first arc groove and the outer surface of the pump shaft enclose a first cavity region, and the second arc groove and the outer surface of the pump shaft enclose a second cavity region. The first cavity region and the second cavity region are connected to form the composite lubrication cavity of the lubrication channel.

8. The sleeve structure of the pump extrusion oil film damper according to claim 1, characterized in that, The platform is located between the first arc groove and the second arc groove, and is perpendicular to the axis of the first arc groove and the axis of the second arc groove. The platform is used to form a transition area when the lubricating medium flows from the first arc groove to the second arc groove.

9. The sleeve structure of the pump extrusion film damper according to claim 1, characterized in that, The inner ring of the damper is provided with a gap between itself and the pump shaft, which allows it to communicate axially with the first arc groove of the two sleeve bases, so that the lubricating medium can flow to the lubrication channels of the two sleeve bases.

10. The sleeve structure of the pump extrusion film damper according to claim 1, characterized in that, The sleeve base is connected to the inner ring of the damper by bolts, and the two sleeve bases are symmetrically installed on the inner ring of the damper.

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