A salt-proof ocean high-pressure water pump port ring structure based on coupled oscillation

Abstract

The application provides a salt-preventing ocean high-pressure water pump port ring structure based on coupled oscillation, and belongs to the technical field of ocean water pump equipment, and comprises a pump body port ring and an impeller port ring, and an annular gap is formed between the two; a nozzle-shaped first groove is arranged on the inner circumferential surface of the pump body port ring, and a second groove with an inclined wall surface and a backflow channel is arranged on the outer circumferential surface of the impeller port ring; the first groove and the second groove are connected to form a fluid oscillation channel. Through the matching design of the circumferential interval of the groove and the rotating speed of the impeller, the groove connection-separation frequency reaches the ultrasonic frequency band, and double coupling of fluid self-excitation oscillation and ultrasonic vibration is realized. The application effectively prevents salt deposition under the premise of not changing the existing lubrication mode, and significantly improves the water film lubrication performance and the service life of the equipment.

Description

Technical Field

[0001] This invention relates to the field of marine water pump equipment technology, specifically to a salt-resistant marine high-pressure water pump inlet ring structure based on coupled oscillation. Background Technology

[0002] Marine high-pressure water pumps are key power equipment in marine engineering applications such as seawater desalination, deep-sea resource extraction, ship ballast systems, and offshore platform cooling. They operate under extreme conditions of high pressure, high speed, and high salinity for extended periods. These devices typically require the continuous transport of seawater with a salinity of 3% to 5%, with impeller speeds reaching thousands of revolutions per minute and linear velocities at the impeller inlet ring often exceeding tens of meters per second. Under these conditions, the tiny annular gap between the pump body inlet ring and the impeller inlet ring serves a dual function of sealing and lubrication. The seawater within the gap forms a dynamic pressure water film under high-speed shearing, preventing high-pressure fluid leakage from the pump chamber to the suction end and providing fluid lubrication between the relatively moving solid surfaces, thus avoiding direct metal-to-metal contact.

[0003] However, existing marine high-pressure water pumps have long been plagued by a series of problems caused by salt precipitation and adhesion during actual operation. The mechanism is as follows: when seawater flows at high speed within the mouth ring gap, the pressure along the flow direction gradually decreases, while local temperature rises due to viscous dissipation. These two factors work together to disrupt the dissolution equilibrium of salt in the seawater, causing supersaturated salt to precipitate and form fine crystals within the gap. Even more problematic is that the precipitated salt crystals quickly adhere to the metal surface of the mouth ring, especially in the throat region where the gap size is smallest and the flow velocity is highest. Salt adhesion causes irregular changes in the gap geometry, and some gaps may be filled with salt scale, disrupting the continuity of the water film. Simultaneously, the rough surface of the adhesion layer rapidly deteriorates the friction pair from a fluid lubrication state to mixed lubrication or even boundary lubrication. Once the lubrication state deteriorates, the mouth ring material will experience severe wear, and the resulting wear debris further exacerbates gap blockage and surface damage, creating a vicious cycle. In engineering practice, the resulting problems manifest as decreased pump efficiency, increased energy consumption, and intensified vibration and noise. In severe cases, it can lead to rotor dynamic imbalance, shaft wear, or even shaft seizure, greatly affecting the operational reliability and continuous operation capability of marine engineering equipment.

[0004] To address the aforementioned problems, those skilled in the art have attempted various improvement solutions. Early solutions primarily focused on optimizing the size of the mouth ring gap and upgrading materials, such as reducing leakage by narrowing the gap or using high-hardness, corrosion-resistant duplex stainless steel or ceramic coatings to delay wear. However, while simply narrowing the gap reduces leakage to some extent, it significantly increases the risk of salt blockage; the application of wear-resistant materials can only passively withstand the consequences of salt adhesion and cannot fundamentally prevent salt precipitation and deposition. In recent years, some studies have attempted to create groove structures on a single mouth ring surface, trying to optimize the flow field by changing the flow channel shape. However, the disturbance to the flow field caused by such fixed groove structures is static, and their disruptive effect on salt precipitation conditions is very limited. Furthermore, they are difficult to adapt to dynamic changes in operating parameters such as rotational speed and pressure, and their effectiveness is minimal under high-pressure and high-speed conditions. Another technical solution attempts to add chemical scale inhibitors to seawater, but marine engineering has extremely stringent environmental protection requirements, and the addition of chemical agents is strictly limited. Moreover, under high-flow continuous transport conditions, the cost is too high and the feasibility is poor.

[0005] Therefore, existing technologies have consistently failed to fundamentally solve the problem of dynamic salt precipitation and adhesion within the gap between the mouth rings. The main reason is the lack of an effective means to actively intervene in the salt precipitation process while simultaneously removing the adhered salt. How to suppress salt precipitation and remove adhered salt without changing existing lubrication methods or adding chemical agents has become a pressing technical challenge in this field. Summary of the Invention

[0006] To address the technical shortcomings of existing marine high-pressure water pump inlet ring structures, which are prone to salt precipitation and salt adhesion, leading to water film damage and increased friction, this invention provides a salt-resistant marine high-pressure water pump inlet ring structure based on coupled oscillation. By segmenting grooves on the surfaces of the impeller and pump body inlet rings, a dynamic fluid oscillator structure is formed by the impeller rotation, generating a pulsed, unstable liquid flow. Simultaneously, combined with a speed matching design, the groove structure generates ultrasonic vibration. This achieves the dual effects of salt precipitation suppression and the destruction of deposited salt. Furthermore, the aforementioned water flow disturbance is only microscopic vibration and left-right pulses, not affecting the overall water film stability, thereby improving the lubrication performance of the interstitial water film and extending the service life of the equipment.

[0007] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0008] A salt-resistant marine high-pressure water pump inlet ring structure based on coupled oscillation includes a pump body inlet ring and an impeller inlet ring that cooperate with each other. The pump body inlet ring is installed inside the pump casing, and the impeller inlet ring is coaxially installed with the pump body inlet ring at the end of the impeller hub, with an annular gap forming between the pump body inlet ring and the impeller inlet ring; characterized in that:

[0009] The pump body inlet ring has several first grooves evenly provided along the circumferential direction on its inner circumferential surface, and the first grooves are nozzle-shaped.

[0010] The impeller inlet ring has a plurality of second grooves evenly provided along the circumferential direction on its outer circumferential surface; the second groove includes a cavity, the cavity has inclined attached wall surfaces on both sides, the inclined attached wall surfaces have a return channel, the return channel is connected to the cavity, and the rear end of the cavity has a channel outlet connected to the cavity.

[0011] The structural parameters of the first groove and the second groove are matched. When the impeller inlet ring rotates with the impeller to a preset position, the first groove and the corresponding second groove are connected to form a complete fluid oscillation channel.

[0012] Furthermore, the circumferential spacing h of the first groove in the pump body inlet ring is adapted to the rated speed of the impeller, so that the impeller inlet ring is excited with an ultrasonic vibration frequency not lower than the set value when the impeller rotates.

[0013] Furthermore, let the set frequency be f, in Hz; the outer circumferential diameter of the impeller inlet ring be d, in meters; the rated speed of the impeller be n, in r / min; and the circumferential spacing h of the first grooves satisfy the following relationship:

[0014] .

[0015] Furthermore, the frequency f is set to 20~30kHz.

[0016] Furthermore, the first groove forms an array structure that is axially interlaced and circumferentially distributed on the inner circumferential surface of the pump body inlet ring; the second groove forms an array structure that is axially and circumferentially distributed on the outer circumferential surface of the impeller inlet ring.

[0017] Furthermore, the first grooves on the inner circumferential surface of the pump body inlet ring are evenly distributed along the circumferential direction at intervals h, and the interval between adjacent first grooves along the axial direction is h / z, where z is the number of grooves distributed on a single generatrix.

[0018] The second groove on the outer circumferential surface of the impeller mouth ring is evenly distributed along the circumferential direction at intervals h, and the number of grooves distributed on a single generatrix is ​​z. Adjacent grooves along the axial direction are arranged in a straight line.

[0019] Furthermore, the outlet of the second trench is nozzle-shaped, and when it docks with the nozzle-shaped structure of the first trench, it forms a continuous change in the flow channel cross-section.

[0020] Furthermore, the return channel is located on the inclined wall surface, with its inlet located on the side near the channel outlet and its outlet located on the side near the cavity inlet. This is used to guide a portion of the fluid near the channel outlet back to the cavity inlet area to trigger the periodic switching of the flow-attached wall surface.

[0021] Furthermore, the base material of the pump body inlet ring and the impeller inlet ring is duplex stainless steel or high-chromium cast iron, and a nitriding layer is provided on its surface, the thickness of which is 0.1 mm to 0.3 mm.

[0022] Furthermore, both the first and second grooves are made using ultrashort pulse laser processing, and the roughness of the inner wall of the groove, the inner surface of the pump body inlet ring, and the outer surface of the impeller inlet ring is no greater than 0.8 μm.

[0023] The beneficial effects of this invention are as follows:

[0024] 1. The salt-resistant marine high-pressure water pump inlet ring structure based on coupled oscillation described in this invention, by setting a second groove with an inclined wall surface and a return channel on the outer circumferential surface of the impeller inlet ring, when the fluid is accelerated through the first groove of the pump body inlet ring and injected into the cavity of the second groove, the jet periodically switches between the two wall surfaces, forming self-excited oscillation; after the self-excited oscillation is ejected from the channel outlet, it generates a periodic left-right sweeping effect on the water film in the working gap, thereby forming a continuous high-frequency impact and scouring on the salt crystals already attached to the surface of the inlet ring, peeling them off the wall surface and carrying them away with the water flow, achieving the effect of removing salt deposits and restoring surface smoothness.

[0025] 2. The salt-resistant marine high-pressure water pump inlet ring structure based on coupled oscillation described in this invention matches the circumferential spacing h of the first groove with the rated speed of the impeller, so that the periodic docking-separation frequency of the first and second grooves during rotation reaches the ultrasonic band (≥20kHz). High-frequency mechanical vibration is transmitted to the seawater within the gap through the inlet ring structure, inducing ultrasonic cavitation. The localized high temperature, high pressure, and microjets released during the generation and collapse of cavitation bubbles can disrupt the crystallization conditions of salt at the microscopic level, breaking up unstable microcrystalline nuclei, thereby inhibiting salt leaching and blocking crystal growth.

[0026] 3. The salt-resistant marine high-pressure water pump inlet ring structure based on coupled oscillation described in this invention utilizes fluid oscillation primarily for the mechanical stripping of already attached salt, while ultrasonic vibration acts at the microscopic scale, focusing on suppressing the source of salt leaching. Both enhance fluid oscillation, intensify mass transfer within the gap, and rapidly remove the fine crystal nuclei generated by ultrasonic cavitation; ultrasonic vibration further enhances the disturbance intensity of the oscillating jet, thus achieving a fundamental solution to the salt damage problem.

[0027] 4. The salt-resistant marine high-pressure water pump inlet ring structure based on coupled oscillation described in this invention achieves multi-channel coordinated oscillation through a groove array arrangement. In this invention, the first groove is set as an axially staggered array structure, and the second groove is set as an axially aligned matrix structure. When the impeller inlet ring rotates, multiple second grooves distributed along the axial direction sequentially connect with multiple first grooves to form a complete channel. This arrangement allows the oscillating jets generated by each groove to be staggered in time and dispersed in space, avoiding the concentrated superposition of oscillation energy and causing impact on mechanical components. At the same time, it forms a continuous and uniform disturbance field along the entire axial length, achieving a balance between enhanced salt resistance and maintaining operational stability.

[0028] 5. The salt-resistant marine high-pressure water pump inlet ring structure based on coupled oscillation described in this invention only requires groove machining on the surfaces of the existing pump body inlet ring and impeller inlet ring, without changing the overall structural layout of the water pump or adding any external power or control system. The grooves are precision machined using ultra-short pulse lasers, and combined with appropriate nitriding treatment processes and surface roughness control, they can withstand long-term corrosion and erosion from seawater. Through the above methods, a comprehensive effect of simple structure, low implementation cost, strong adaptability, and reliable operation is achieved. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are some embodiments of the present invention. For those skilled in the art, it is obvious that other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of the first groove on the inner surface of the pump body inlet ring according to the present invention.

[0031] Figure 2 This is a schematic diagram of the structure of the second groove on the outer surface of the impeller inlet ring according to the present invention.

[0032] Figure 3 This is an assembly diagram of the impeller inlet ring and the pump body inlet ring according to the present invention.

[0033] Figure 4 This is a schematic diagram showing the interaction between the first groove and the second groove described in this invention.

[0034] Figure 5 This is a water flow direction diagram showing the interaction between the first and second channels.

[0035] Figure 6 This is another water flow direction diagram after the first and second channels cooperate with each other.

[0036] Figures 7-11A simulation diagram of water flow sweeping left and right within one cycle, where:

[0037] Figure 7 This is a simulation diagram of the water flow direction at t=0;

[0038] Figure 8 The simulation diagram shows the direction of water flow at t=5e-5s;

[0039] Figure 9 This is a simulation diagram of the water flow direction at t=1e-4s;

[0040] Figure 10 The simulation diagram shows the direction of water flow at t=1.5e-4s;

[0041] Figure 11 The simulation diagram shows the direction of water flow at t=2e-4s.

[0042] In the picture:

[0043] 1-Pump body inlet ring; 2-First groove; 3-Impeller inlet ring; 4-Second groove; 5-Inlet ring working clearance; 6-Cavity; 7-Inclined wall surface; 8-Recirculation channel; 9-Channel outlet. Detailed Implementation

[0044] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0045] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "axial," "radial," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0046] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., 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 according to the specific circumstances.

[0047] like Figure 3 As shown, the salt-resistant marine high-pressure water pump inlet ring structure based on coupled oscillation described in this invention is suitable for centrifugal pumps or mixed-flow pumps operating for extended periods in high-pressure, high-speed, and high-salinity seawater. It includes a pump body inlet ring 1 and an impeller inlet ring 3 that cooperate with each other. The pump body inlet ring 1 is installed inside the pump casing, and the impeller inlet ring 3 is coaxially mounted with the pump body inlet ring 1 at the end of the impeller hub, rotating with the impeller. After assembly, an annular gap 5 is formed between the pump body inlet ring 1 and the impeller inlet ring 3. The initial design size of the annular gap 5 directly affects the quality of water film formation and leakage control; in this embodiment, it is preferably 0.1 mm to 0.3 mm. Within this gap range, the seawater within the gap can form a dynamic pressure water film with sufficient load-bearing capacity when the impeller rotates at high speed, while controlling leakage to an acceptable level.

[0048] like Figure 1 As shown, the first groove 2 forms an array structure that is axially staggered and circumferentially evenly distributed on the inner circumferential surface of the pump body inlet ring 1; the first groove 2 is nozzle-shaped; the first groove 2 on the inner circumferential surface of the pump body inlet ring 1 is evenly distributed at intervals h along the circumferential direction, and the interval between adjacent first grooves 2 along the axial direction is h / z, where z is the number of grooves distributed on a single generatrix. Figure 1As can be seen, along the axial direction, two adjacent first grooves 2 are not on a straight line, but are staggered by a certain distance. This distance is the circumferential spacing h / z. For ease of understanding, the inner circumferential surface of the pump body inlet ring 1 is unfolded into a rectangle, with the length direction being the axial direction and the width direction being the circumferential direction. The first grooves 2 are arranged in a rectangular array within the rectangle, where z is the number of first grooves 2 in the axial direction and w is the number of first grooves 2 in the circumferential direction. The circumferential spacing between adjacent first grooves 2 in the same column (circumferential column) is h, and the spacing between adjacent first grooves 2 in the same row (axial row) is h / z. This arrangement forms an axially staggered and circumferentially distributed array structure on the inner circumferential surface of the pump body inlet ring 1. The purpose is to stagger the oscillating jets generated by subsequent grooves in time and disperse them in space, avoiding excessive superposition of oscillating energy and adverse effects on mechanical components. The cross-sectional profile of the first groove 2 is designed as a converging nozzle shape, with a larger inlet end cross-section that gradually narrows along the flow direction. This structural design aims to accelerate and rectify the fluid entering the gap, forming a jet with stable initial momentum and a clear direction, providing the necessary kinetic energy basis for the subsequent oscillation process after entering the second groove 4.

[0049] like Figure 2 As shown, several second grooves 4 are also uniformly formed circumferentially on the outer circumferential surface of the impeller inlet ring 3. These second grooves 4 are also uniformly distributed at intervals h in the circumferential direction, and there are z rows of second grooves 4 distributed axially. Unlike the arrangement of the first grooves 2, adjacent grooves along the axial direction are arranged in a straight line, i.e., the interval is 0. This results in the second grooves 4 forming a matrix structure on the outer circumferential surface of the impeller inlet ring 3 that is axially aligned and circumferentially distributed. The purpose of this structural design is to ensure that when the impeller inlet ring 3 rotates to a specific angle, the multiple axially distributed second grooves 4 can sequentially align with the multiple first grooves 2 on the pump body inlet ring 1, forming a complete flow path.

[0050] like Figure 4As shown, the second groove 4 is the main structure for generating fluid oscillations, including a cavity 6, inclined attached walls 7, a return channel 8, and a channel outlet 9. The cavity 6 is located in the front middle part of the second groove 4 and is a relatively open space. The inlet end of the cavity 6 matches the outlet end of the first groove 2 in shape and size, forming a smooth transition flow channel when they are connected, reducing flow loss. Inclined attached walls 7 are provided on both sides of the cavity 6, symmetrically inclined, forming a certain angle with the mainstream direction. The function of the inclined attached walls 7 is to guide the jet to generate the attachment effect, providing a structural basis for subsequent periodic switching. Return channels 8 are provided on the inclined attached walls 7 on both sides. The cross-sectional area of ​​the return channel 8 is at least three times smaller than the cross-sectional area of ​​the cavity 6, and can be regarded as a small channel (relative to the cavity 6). The inlet of the return channel 8 is located near the channel outlet 9, and the outlet extends to the vicinity of the inlet of the cavity 6, connecting with the interior of the cavity 6. The function of the return channel 8 is to guide a portion of the high-pressure fluid near the channel outlet 9 back to the inlet area of ​​the cavity 6, thereby triggering and maintaining the periodic switching of the jet's wall surface. The rear end of the cavity 6 is provided with a channel outlet 9 communicating with the cavity 6; the channel outlet 9 is preferably a nozzle-shaped structure, its purpose being to spray the oscillated fluid into the working gap 5 at a certain speed and angle. When the nozzle-shaped structure of the first groove 2 aligns with the nozzle-shaped channel outlet 9 of the second groove 4, a continuous change in the flow channel cross-section is formed, which is beneficial for maintaining flow stability.

[0051] The structural parameters of the first groove 2 and the second groove 4 are matched. When the impeller inlet ring 3 rotates with the impeller to a preset position, the first groove 2 and the corresponding second groove 4 are connected to form a complete fluid oscillation channel.

[0052] The axial fit between the first groove 2 and the second groove 4 is crucial to ensuring the uniformity of the oscillation effect. For example... Figure 1 , Figure 2 and Figure 4 As shown, when the impeller inlet ring 3 rotates with the impeller, the z second grooves 4 arranged axially along the impeller inlet ring 3 will sequentially form a complete fluid oscillation channel with the z first grooves 2 arranged axially along the pump body inlet ring 1 during rotation. Specifically, at a certain moment, the first second groove 4 located upstream aligns with the first first groove 2; after rotating a small angle, the second groove 4 is offset from the first groove 2, and the second second groove 4 begins to align with the second first groove 2. During this process, some grooves are always in an aligned state along the axial direction, thus forming a continuous and uniform disturbance field along the entire length of the gap. This ensures the continuity of the anti-salt effect and avoids the superposition of pressure pulsations that may be caused by all grooves aligning simultaneously.

[0053] When the impeller inlet ring 3 rotates, the second groove 4 on its surface periodically passes through the first groove 2 on the surface of the pump body inlet ring 1. The frequency of this docking-separation process depends on the linear velocity of the impeller inlet ring 3 and the circumferential spacing h of the grooves. When this frequency reaches the ultrasonic band, ultrasonic vibrations can be excited in the inlet ring structure, which are then transmitted to the interstitial water film to generate a cavitation effect. To achieve the ultrasonic vibration effect, the circumferential spacing h of the first groove 2 must meet the following requirements:

[0054] Let the set frequency be f, in Hz, and in this embodiment, the set frequency f is 20~30kHz; the outer circumferential diameter of the impeller inlet ring 3 is d, in meters; the rated speed of the impeller is n, in r / min; the circumferential spacing h of the first groove 2 satisfies the following relationship:

[0055] .

[0056] For water pumps of different specifications, the upper limit of the circumferential groove spacing h can be determined by this formula based on the actual impeller outer diameter d and rated speed n, thereby ensuring the realization of the ultrasonic vibration effect.

[0057] To ensure the reliability and lifespan of the impeller inlet ring 3 and the pump body inlet ring 1 in a seawater environment, the base materials of the pump body inlet ring 1 and the impeller inlet ring 3 in this embodiment are preferably duplex stainless steel or high-chromium cast iron. These two types of materials exhibit good resistance to pitting and crevice corrosion in seawater environments. To further improve surface hardness and wear resistance, the surfaces of the impeller inlet ring 3 and the pump body inlet ring 1 are nitrided, with the thickness of the nitrided layer controlled between 0.1 mm and 0.3 mm. The nitrided layer not only improves wear resistance but also reduces the adhesion between salt and the metal surface to a certain extent, facilitating its removal by the oscillating jet.

[0058] The first groove 2 and the second groove 4 are typically on the millimeter to sub-millimeter scale, which is difficult to achieve using traditional machining methods. This embodiment preferably uses ultrashort pulse laser processing technology for shaping. This technology has advantages such as a small heat-affected zone, high processing accuracy, and good surface quality, and can accurately process complex three-dimensional structures such as wall-attached surfaces and return channels. After processing, the surface roughness of the inner wall of the groove and the mating surface of the mouth ring needs to be controlled, requiring that their arithmetic mean roughness Ra is no greater than 0.8 μm. Lower surface roughness helps reduce fluid flow resistance and also reduces the probability of salt adhesion and nucleation.

[0059] Working principle:

[0060] During operation, the mouth ring structure of this invention achieves anti-salt deposition and water film optimization through the dual effects of dynamic flow field disturbance and ultrasonic vibration. The specific working principle is as follows:

[0061] 1. Dynamic fluid oscillation effect:

[0062] like Figure 5 and Figure 6 As shown, when the marine high-pressure water pump starts, the impeller drives the impeller inlet ring 3 to rotate at high speed. High-pressure seawater, accelerated by the first groove 2 of the pump body inlet ring 1, is injected into the cavity 6 of the second groove 4 of the impeller inlet ring 3 in the form of a jet. Due to minor deviations in the flow channel processing or minor disturbances in the fluid itself, the jet will not remain centered but will spontaneously deflect towards the inclined wall surface 7 on one side of the cavity 6 and flow downstream along that wall surface (wall attachment effect). At this time, most of the fluid is ejected from the channel outlet 9 and enters the working gap 5; a small portion of the fluid is entrained into the return channel 8 on that side, flows back towards the inlet of the cavity 6 through the return channel 8, and finally re-enters the upstream region of the jet.

[0063] The continuous effect of this backflow is equivalent to applying a lateral disturbance force to the main jet. As the backflow flow and pressure accumulate, the jet is gradually pushed away from the current inclined wall surface 7 and suddenly attaches to the opposite inclined wall surface 7. At the same time, the backflow phenomenon also switches to the opposite side; the previously active backflow channel 8 basically stops backflow, while the opposite backflow channel 8 begins to form backflow and gradually accumulates. The above process circulates between the two inclined wall surfaces 7, causing the fluid ejected from the channel outlet 9 to periodically sweep left and right, forming a self-excited oscillating jet.

[0064] Figures 7 to 11 The simulation results clearly demonstrate this process. Figure 7 (t=0) indicates that the jet initially deflects to the left side of the wall; Figure 8 (t=5e-5s) to Figure 9 (t=1e-4s) shows that the backflow gradually accumulates and the jet begins to shift to the right; Figure 10 (t=1.5e-4s) indicates that the jet has completely switched to the right-side wall surface; Figure 11 (t=2e-4s) marks the end of a complete oscillation cycle, at which point the jet switches back to the left side. Simulation results show that the oscillation frequency can reach 20kHz, consistent with the design target.

[0065] The oscillating jet acts directly on the water film within the annular gap, creating a continuous high-frequency mechanical impact on the precipitated salt crystals and the existing salt layer. On one hand, the oscillating flow disrupts the stable fluid environment required for salt precipitation, making it difficult to maintain a supersaturated state; on the other hand, the sweeping action of the oscillating flow washes away the salt already attached to the wall surface, carrying it away with the mainstream, thus keeping the annular surface clean.

[0066] 2. Ultrasonic vibration effect

[0067] As mentioned earlier, by designing the circumferential spacing h of the first groove 2 to satisfy... Under the condition (f=20kHz in this embodiment), the docking-separation process between the first groove 2 and the second groove 4 occurs at a frequency exceeding 20kHz when the impeller ring 3 rotates. This high-frequency dynamic process is equivalent to a miniature impact source, exciting ultrasonic vibrations within the ring structure. This vibration is directly transmitted through the solid structure to the water film within the working gap 5, triggering ultrasonic cavitation in the seawater. The cavitation effect manifests as tiny cavitation bubbles in the seawater forming in the ultrasonic negative pressure phase and rapidly collapsing in the positive pressure phase. At the moment of cavitation bubble collapse, shock waves with pressures reaching thousands of atmospheres and micro-jets with speeds reaching hundreds of meters per second are generated locally. The ultrasonic cavitation effect can achieve the following functions at the microscopic level: firstly, it breaks up unstable, fine salt crystal nuclei, preventing them from growing into scale; secondly, it causes fatigue damage to the formed salt layer, reducing its bonding strength with the wall surface; and thirdly, it enhances the kinematic activity of water molecules, improves the fluidity and uniformity of the water film, and improves lubrication.

[0068] 3. Dual synergistic effect

[0069] The two effects described above are simultaneously achieved within the same structure, forming a mutually reinforcing synergistic effect. Fluid oscillation primarily acts on the macroscopic scale, focusing on the mechanical stripping and transport of already adhered salts; ultrasonic vibration acts on the microscopic scale, focusing on suppressing the salt leaching process at its source and preventing fatigue damage to existing salt layers. Fluid oscillation intensifies mass transfer within the gap, rapidly carrying away the fine crystal nuclei generated by ultrasonic cavitation and preventing their re-adhesion; ultrasonic vibration enhances the disturbance intensity of the oscillating jet, making its scouring effect more significant. Through the synergistic effect of inhibition and adhesion, a fundamental solution to the salt damage problem is achieved. Furthermore, both dynamic fluid oscillation and ultrasonic vibration create unstable flow locally within the water film, without affecting the overall stability of mechanical components such as the pump body and impeller, thus ensuring the long-term effectiveness of water film lubrication.

[0070] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0071] The detailed descriptions listed above are merely specific illustrations of feasible embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A salt-resistant marine high-pressure water pump inlet ring structure based on coupled oscillation, comprising a pump body inlet ring (1) and an impeller inlet ring (3) that cooperate with each other, wherein the pump body inlet ring (1) is installed inside the pump casing, and the impeller inlet ring (3) is coaxially installed with the pump body inlet ring (1) at the end of the impeller hub, and an annular gap (5) is formed between the pump body inlet ring (1) and the impeller inlet ring (3); characterized in that: The pump body inlet ring (1) has a plurality of first grooves (2) evenly provided along the circumferential direction on the inner circumferential surface, and the first grooves (2) are nozzle-shaped. The impeller inlet ring (3) has several second grooves (4) evenly arranged along the circumferential direction on its outer circumferential surface; the second groove (4) includes a cavity (6), the cavity (6) has inclined attached wall surfaces (7) on both sides, the inclined attached wall surfaces (7) have a return channel (8) connected to the cavity (6), and the rear end of the cavity (6) has a channel outlet (9) connected to the cavity (6); The structural parameters of the first groove (2) and the second groove (4) are matched. When the impeller inlet ring (3) rotates with the impeller to the preset position, the first groove (2) and the corresponding second groove (4) are connected to form a complete fluid oscillation channel.

2. The salt-resistant marine high-pressure water pump inlet ring structure based on coupled oscillation according to claim 1, characterized in that, The first groove (2) is spaced h around the pump body inlet ring (1) to match the rated speed of the impeller, so that the impeller inlet ring (3) is excited with an ultrasonic vibration frequency not lower than the set value when the impeller rotates.

3. The salt-resistant marine high-pressure water pump inlet ring structure based on coupled oscillation according to claim 2, characterized in that, it is provided that... The set frequency is f, in Hz; the outer circumferential diameter of the impeller inlet ring (3) is d, in m; the rated speed of the impeller is n, in r / min; the circumferential spacing h of the first groove (2) satisfies the following relationship: 。 4. The salt-resistant marine high-pressure water pump inlet ring structure based on coupled oscillation according to claim 2, characterized in that, The frequency f is set to 20~30kHz.

5. The salt-resistant marine high-pressure water pump inlet ring structure based on coupled oscillation according to claim 2, characterized in that, The first groove (2) forms an array structure that is axially intersecting and circumferentially distributed on the inner circumferential surface of the pump body inlet ring (1); the second groove (4) forms an array structure that is axially and circumferentially distributed on the outer circumferential surface of the impeller inlet ring (3).

6. The salt-resistant marine high-pressure water pump inlet ring structure based on coupled oscillation according to claim 5, characterized in that, The first groove (2) on the inner circumferential surface of the pump body inlet ring (1) is evenly distributed along the circumferential direction at intervals h, and the interval between adjacent first grooves (2) along the axial direction is h / z, where z is the number of grooves distributed on a single generatrix; the second groove (4) on the outer circumferential surface of the impeller inlet ring (3) is evenly distributed along the circumferential direction at intervals h, and the number of grooves distributed on a single generatrix is ​​z, and adjacent grooves along the axial direction are arranged in a straight line.

7. The salt-resistant marine high-pressure water pump inlet ring structure based on coupled oscillation according to claim 1, characterized in that, The channel outlet (9) of the second groove (4) is nozzle-shaped, and when it docks with the nozzle-shaped structure of the first groove (2), it forms a continuous change in the flow channel cross section.

8. The salt-resistant marine high-pressure water pump inlet ring structure based on coupled oscillation according to claim 1, characterized in that, The return channel (8) is located on the inclined wall surface (7), with its inlet located on the side near the channel outlet (9) and its outlet located on the side near the cavity (6) inlet. It is used to guide a portion of the fluid near the channel outlet (9) back to the cavity (6) inlet area to trigger the periodic switching of the return wall surface.

9. The salt-resistant marine high-pressure water pump inlet ring structure based on coupled oscillation according to claim 1, characterized in that, The base material of the pump body inlet ring (1) and the impeller inlet ring (3) is duplex stainless steel or high chromium cast iron, and a nitriding layer is provided on its surface, the thickness of which is 0.1 mm to 0.3 mm.

10. The salt-resistant marine high-pressure water pump inlet ring structure based on coupled oscillation according to claim 1, characterized in that, The first groove (2) and the second groove (4) are both made by ultra-short pulse laser processing, and the roughness of the inner wall of the groove, the inner surface of the pump body inlet ring (1), and the outer surface of the impeller inlet ring (3) is not greater than 0.8μm.

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