A high efficiency composite polishing and strengthening device and method for the inner surface of a porous part

Abstract

The application discloses a kind of high-efficiency composite polishing reinforced porous part inner surface device and method, left and right atomization film outside each adhere to one drive motor, left and right cylinder gradually reduce the inner diameter from middle to inner end to form cone, cylinder inner wall is equipped with cylinder spiral flow guide groove, the part to be processed is porous part, fixedly compressed and connected between left cavitation generation plate and right cavitation generation plate, cavitation generation plate center is opened with multiple cavitation generation channels, multiple cavitation generation channels are one-to-one opposite with the porous position on the part to be processed, each cavitation generation channel is composed of water inlet, throat and water outlet in turn, throat inner wall is equipped with throat spiral flow guide groove;Two drive motors work simultaneously, left and right atomization film are vibrated towards with same frequency, realize inner wall polishing and reinforcement;Spiral flow guide groove induces turbulence intensity multiplication, pre-cavitation energy efficiency increases, eliminates processing blind area, can realize porous groove simultaneous processing each time, improve work efficiency.

Description

Technical Field

[0001] This invention belongs to the field of machining, and particularly relates to the processing, strengthening and shaping of the inner wall surface of parts using alternating volume and cavitation water jet. Background Technology

[0002] Waterjet cavitation technology is an advanced technique that utilizes the cavitation effect generated by high-speed water jets. The shock waves caused by bubble collapse enable cutting, cleaning, and surface treatment. It excels at removing dirt, paint, and coatings and is widely used in surface treatment and cleaning. When a high-speed water jet is sprayed onto a target surface, some of the water is rapidly depressurized, forming tiny bubbles—a process known as cavitation. These bubbles undergo pressure changes as the water flows. When the water flow stops or changes direction, the bubbles collapse, generating shock waves that produce extremely high pressure in a very short time. These high-pressure shock waves are used for cutting, cleaning, or surface treatment. High-speed water jets generated by high-pressure pumps are channeled through special nozzles to form a high-speed jet, providing sufficient kinetic energy for cutting and cleaning. Because the cutting process primarily relies on the water flow and the shock waves generated by bubble collapse, waterjet cavitation technology is suitable for various materials, including metals and concrete. Compared to other mechanical methods, waterjet cavitation technology produces relatively low noise, reducing the impact on the working environment and operators.

[0003] In the field of cavitation jet technology, traditional devices mostly rely on fixed cavities or mechanical volume adjustment (such as pistons and diaphragms) to control jet parameters. Fixed cavity structures cannot dynamically adapt to processing requirements, resulting in rigid adjustments to cavitation intensity and impact direction. While mechanical volume adjustment can change the cavity volume, it suffers from structural complexity, slow response speed, and susceptibility to pressure oscillations, leading to unstable cavitation bubble generation and collapse, thus affecting processing efficiency. Furthermore, multi-cavity collaborative technologies (such as segmented switching or parallel cavities) suffer from switching delays and high energy consumption, making continuous volume alternation difficult. Moreover, the coordination between volume changes and parameters such as jet pressure and abrasive particle concentration is poor, resulting in low energy utilization and insufficient processing consistency. In existing technologies, the volume alternation mechanism lacks deep integration with jet dynamics, making it impossible to achieve high-frequency, precise dynamic volume control without mechanical drive, thus limiting the application potential of cavitation jet technology under complex working conditions.

[0004] The polishing device disclosed in Chinese Patent Publication No. CN113736968A, entitled "A Polishing Device and Polishing Method for the Inner Wall Surface of an Inner Hole Groove", includes an upper piston, a lower outer piston, a lower inner piston, a nozzle mechanism, and a drive mechanism. The nozzle mechanism is disposed on the lower outer piston, and the nozzle is located in the inner hole groove. The drive mechanism drives the lower inner piston to move up and down, causing the liquid pressure in the inner hole groove to change and generate cavitation. The composite nozzle generates a water jet, which is evenly sprayed to various positions in the inner hole groove, thereby improving the surface quality of the inner hole groove. However, the volume change in one working cycle is only generated by the nozzle at one end of the inner hole groove to generate cavitation, resulting in a weak impact strengthening effect. Moreover, only one inner hole groove can be processed at a time, and the assembly and disassembly steps for each work are relatively complicated.

[0005] The principle of a volumetric alternating flow device is that when the local pressure of a fluid rapidly decreases below its saturated vapor pressure, tiny bubbles in the liquid rapidly expand and form cavitation bubbles. Subsequently, when the pressure recovers, these cavitation bubbles rapidly collapse, generating strong shock waves and microjets. Current volumetric alternating flow devices generally achieve the alternation of liquid volume through the reciprocating motion of a piston, thereby generating a cavitation effect inside the workpiece being processed. Summary of the Invention

[0006] The purpose of this invention is to solve the problems existing in the prior art and to propose a high-efficiency composite polishing device and method for strengthening the inner surface of porous parts by improving the uniformity and strengthening effect of cavitation effect and processing multiple holes at one time.

[0007] The technical solution of this invention, a high-efficiency composite polishing device for strengthening the inner surface of porous parts, comprises a left cylinder and a right cylinder with identical structures and symmetrical arrangement. Each cylinder has a water inlet at its top. A left atomizing film is sealed to the left end of the left cylinder, and a right atomizing film is sealed to the right end of the right cylinder. A drive motor is attached to the outer side of each atomizing film. The inner diameter of the left and right cylinders gradually decreases from the middle towards the inner end, forming a cone. Spiral guide grooves, evenly distributed circumferentially and spirally extending axially, are provided on the inner wall of the cone. A left cavitation generating plate is sealed to the right end of the left cylinder, and a right cavitation generating plate is sealed to the left end of the right cylinder. The left and right cavitation generating plates have the same structure and are arranged symmetrically. The horizontally placed part to be processed is a porous part, which is fixed and pressed between the left and right cavitation generating plates by rubber rings. The center of the left and right cavitation generating plates has multiple cavitation generating channels, which are directly opposite the porous positions on the part to be processed. Each cavitation generating channel consists of an inlet, a throat, and an outlet connected in sequence. The inlet is located on the outer side away from the part to be processed and is a cylindrical hole. The inner diameter of the throat is smaller than the inner diameter of the inlet, and the inner diameter of the outlet gradually increases. The inner wall of the throat is provided with a throat spiral guide groove that is evenly distributed circumferentially along the inner wall of the throat and spirally extended axially.

[0008] The technical solution of the strengthening process method of the high-efficiency composite polishing strengthening device for the inner surface of porous parts of the present invention includes the following steps:

[0009] Step 1): Simultaneously inject pure water and abrasive particles into the left and right cylinders through the water inlet, so that the sealed space formed by the left cylinder, the inner cavity of the part to be processed, and the right cylinder is filled with water and abrasive particles. After the liquid enters, it is constrained by the spiral guide groove to generate an initial swirling flow, which promotes the uniform dispersion and suspension of the abrasive particles.

[0010] Step 2): The two drive motors work simultaneously, causing the left and right atomizing films to vibrate in opposite directions at the same frequency. When the two films move in opposite directions, the cavity generates volume alternation. When the two films move in opposite directions, the cavity generates a high-frequency acoustic pressure field. The liquid is accelerated at the throat to form a low-pressure zone, and cavitation bubbles are activated and enter the cavity of the part to be processed, thus achieving inner wall polishing and strengthening.

[0011] Step 3): After processing, replace the part to be processed with the left and right cavitation generating plates; when it is necessary to process parts of different specifications or hole distributions, remove the processed parts and replace the left and right cavitation generating plates with the corresponding designs, so that the cavitation channels of the left and right cavitation generating plates correspond one-to-one with the holes of the new parts.

[0012] Compared with the prior art, the present invention has the following outstanding advantages:

[0013] (1) The cylinder and cavitation generation channel in this invention are designed with spiral guide grooves. The spiral guide grooves induce a doubling of turbulence intensity and a significant increase in precavitation energy efficiency. The liquid flows through the spiral grooves to generate high-speed swirling flow. The centrifugal effect overcomes the tendency of abrasive particles to settle, so that the abrasive particles are evenly distributed in the liquid, eliminating processing blind spots and improving the consistency of inner wall reinforcement.

[0014] (2) The present invention can process multiple slots simultaneously in each operation, which greatly improves work efficiency.

[0015] (3) The present invention can both polish the inner surface of the pipe fitting and strengthen the inner surface.

[0016] (4) The present invention achieves alternating cavity volume by high-frequency drum concave of vibrating diaphragm, which overcomes the limitations of traditional piston structure and can generate strong cavitation effect under higher frequency and more stable conditions. It has the advantages of simplified structure, flexible control, high efficiency and strong adaptability.

[0017] (5) In this invention, elastic washers are installed between the piston rod, the cavitation generating plate and the parts to be processed. During operation, the washers buffer the vibration, and the impact generated by the collapse of cavitation bubbles will not directly act on the cavitation generating plate, thereby increasing the durability of the cavitation generating plate.

[0018] (6) This invention achieves several key improvements: first, by replacing mechanical stirring devices with self-generated swirl, energy consumption is reduced and vibration interference is avoided; second, the centrifugal tight-wall effect increases the uniformity of abrasive particle distribution to over 95%, enhancing impact consistency; and third, the swirl expands the boundary layer separation zone at the throat of the cavitation generator, increasing the low-pressure vortex nucleus density and improving the gas nucleus activation efficiency by 35%, ultimately achieving a breakthrough in cavitation energy density and surface strengthening quality. The maintenance cycle is also extended by 40% due to its self-cleaning properties. Attached Figure Description

[0019] Figure 1 This is a front view of the overall structure of the device for high-efficiency composite polishing and strengthening the inner surface of porous parts according to the present invention;

[0020] Figure 2 yes Figure 1 Enlarged assembly diagram of the hollowing plate and the part to be processed;

[0021] Figure 3 yes Figure 1 Enlarged left view of the hollowing plate;

[0022] Figure 4 yes Figure 3 A half-section view;

[0023] Figure 5 yes Figure 1 Enlarged structural schematic diagram of the spiral guide grooves inside the cylinder block;

[0024] Figure 6 yes Figure 1 The diagram shown is an enlarged view illustrating the flow of liquid under a double spiral during compression.

[0025] Figure 7 yes Figure 1 The diagram shown is an enlarged view illustrating the distribution of cavitation bubbles and abrasive particles within the workpiece during compression.

[0026] Explanation of reference numerals in the attached diagram: 1. Left cylinder; 2. Left atomizing film; 3. Right cylinder; 4. Right atomizing film; 5. Part to be processed; 6. Left water inlet; 7. Left water injection pipe; 8. Right water inlet; 9. Right water injection pipe; 10. Left sensor; 11. Right sensor; 12. Left water outlet; 13. Right water outlet; 14. Left bracket; 15. Right bracket; 16. Base; 17. Guide rail; 18. Left cavitation generating plate; 19. Right cavitation generating plate; 20. Bolt; 21. Bolt; 22. Long bolt; 23. Left sealing gasket; 24. Right sealing gasket; 25. Rubber ring; 26. Drive motor; 27. Control power supply; 28. Spiral guide groove in the throat; 29. ​​Spiral guide groove in the cylinder; 30. Water inlet; 31. Throat; 32. Water outlet. Detailed Implementation

[0027] See Figure 1 and Figure 2 This invention discloses a high-efficiency composite polishing device for strengthening the inner surface of porous parts, comprising two cylinders and two corresponding atomizing films. The two cylinders are identical in structure, namely a left cylinder 1 and a right cylinder 3, arranged symmetrically from left to right, with their central axes collinear. The two atomizing films are a left atomizing film 2 and a right atomizing film 4, also arranged symmetrically from left to right. The left atomizing film 2 and the right atomizing film 4 can complete one displacement cycle in milliseconds or microseconds, and the driving frequency can cover the range of tens of hertz to tens of kilohertz.

[0028] The left atomizing film 2 is sealed to the left end of the left cylinder 1, forming a closed chamber. The outer side of the left atomizing film 2 is attached to the first drive motor 26, which is connected to the first control power supply 27 to provide a periodic alternating voltage signal, causing the film of the left atomizing film 2 to vibrate axially. The inner diameter of the left cylinder 1 gradually decreases from the middle to the right end, forming a cone.

[0029] The right atomizing film 4 is sealed to the right end of the right cylinder 3, forming a closed chamber. The outer side of the right atomizing film 4 is attached to the second drive motor 26, which is connected to the second control power supply 27 to provide a periodic alternating voltage signal, causing the film of the right atomizing film 4 to vibrate axially. The inner diameter of the right cylinder 3 gradually decreases from the middle to the left, forming a cone.

[0030] The left cylinder 1 is sealed at the right end and connected to the left cavitation generating plate 18. The right cylinder 3 is sealed at the left end and fixed to the right cavitation generating plate 19. The left cavitation generating plate 18 and the right cavitation generating plate 19 have the same structure and are arranged symmetrically on the left and right. The central axis of the left cavitation generating plate 18 and the right cavitation generating plate 19 is collinear with the central axis of the left cylinder 1 and the right cylinder 3.

[0031] There is a space between the left cylinder 1 and the right cylinder 3 for the part 5 to be processed. The part 5 is a porous part, which is placed horizontally between the left cylinder 1 and the right cylinder 3. It is fixed and pressed between the left cavitation generating plate 18 and the right cavitation generating plate 19 by the rubber ring 25. The multiple holes on the part 5 face the two cylinders and communicate with the left cylinder 1 and the right cylinder 3, so that the interior of the left cylinder 1 and the right cylinder 3 and the interior of the multiple holes on the part 5 to be processed form a sealed cavity. When the left atomizing film 2 and the right atomizing film 4 vibrate at high frequency, they can drive the volume of the sealed cavity to change alternately, realizing volume alternation.

[0032] The left cylinder 1 has a left water inlet 6 at its top, which allows water and abrasive particles to be injected into the left cylinder 1. A solenoid valve controls the opening and closing of the left water inlet 6, and a left water inlet pipe 7 connects to the top of the left water inlet 6. Similarly, the right cylinder 3 has a right water inlet 8 at its top, which allows water and abrasive particles to be injected into the right cylinder 3. A solenoid valve controls the opening and closing of the right water inlet 8, and a right water inlet pipe 9 connects to the top of the right water inlet 8.

[0033] A pressure sensor is installed in both the left cylinder 1 and the right cylinder 3, namely the left sensor 10 and the right sensor 11. Both are high-precision pressure sensors (range 0-20MPa, accuracy ±0.5%), which can monitor the pressure fluctuations in the corresponding cavities in real time. When the pressure exceeds the preset threshold (such as 12MPa) or abnormal pressure oscillation is detected, the solenoid valves at the left outlet 12 and the right outlet 13 open simultaneously to release pressure.

[0034] There is a water outlet at the bottom of both the left cylinder 1 and the right cylinder 3, namely the left outlet 12 and the right outlet 13. Each outlet is equipped with a solenoid valve to control its opening and closing. After the device has finished operating, opening the left outlet 12 and the right outlet 13 allows the internal abrasive particles and waste water to be drained.

[0035] The left cylinder 1 and right cylinder 3 are each connected to the base 16 via a bracket. The base 16 is horizontally arranged. The cylinder of the left cylinder 1 is fixed to the base 16 via a left bracket 14, which is vertically arranged. The left cylinder 1 is perpendicular to the left bracket 14. The right cylinder 3 is fixedly connected to the right bracket 15, which is a bracket that can move horizontally left and right. It is connected to the base 16. The base 16 is provided with a guide rail 17, which consists of two T-shaped bosses. The length direction of the T-shaped bosses is consistent with the central axis direction of the right cylinder 3. The bottom of the right bracket 15 is provided with two T-shaped grooves. The two T-shaped bosses on the base 16 cooperate with the two T-shaped grooves at the bottom of the right bracket 15, so that the right bracket 15 can be arranged on the guide rail and can move horizontally on the guide rail 17.

[0036] The left cylinder 1 and right cylinder 3 are located on the side closest to the workpiece 5. The ends of the cylinders are flange-shaped with through holes. The left cavitation generating plate 18 and right cavitation generating plate 19 are respectively attached to the left cylinder 1 and right cylinder 3 on the side closest to the workpiece 5. The left cavitation generating plate 18 is positioned on the right side of the left cylinder 1, and is collinear with the central axis of the left cylinder 1. Bolts 20 and 21 connect the upper and lower sides of the flanges of the left cylinder 1 and right cylinder 3 respectively, fixing the left cavitation generating plate 18 and right cavitation generating plate 19 to their corresponding left and right cylinder 1 and right cylinder 3. Bolts 20 and 21 first pass through the corresponding left sealing gasket 23 and right sealing gasket 24, then through the through holes on the flange discs, then through the gaskets, and after passing through the through holes of the cavitation generating plates, they pass through the elastic rubber ring 25. A nut is then screwed onto the other end to complete the fixation. Elastic gaskets are placed between each pair of contact surfaces to ensure that the surface of the device is not scratched by the hardware and to extend the service life of the overall device.

[0037] The left cavitation generating plate 18 and the right cavitation generating plate 19 are at the same height, with a pair of through holes at the top and bottom of each plate. The central axes of the through holes are horizontally collinear. Two long bolts 22 clamp the left cavitation generating plate 18 and the right cavitation generating plate 19 to the workpiece 5, generating a certain preload. This ensures that there is no relative displacement between the left cavitation generating plate 18 and the right cavitation generating plate 19 and the workpiece 5 during processing, thus guaranteeing the stability of the overall device. An elastic rubber ring 25 is installed at the contact surface between the head of the long bolt 22 and the cavitation generating plate, ensuring clamping without damaging the cavitation generating plate.

[0038] The annular sealing gaskets located between the cylinder flange disc and the cavitation generating plate are designated as left sealing gasket 23 and right sealing gasket 24. The outer diameter of both gaskets is smaller than the flange disc diameter, while their inner diameter is greater than or equal to the sum of the outer diameters of multiple holes on the workpiece 5. This ensures that the gaskets do not interfere with the entry of liquid into the cavitation channel during operation. They are secured by an interference fit, forming a radially uniformly compressed sealing interface. Both gaskets are made of fluororubber, which adapts to pressure and is suitable for high-pressure (≤10MPa) and high-temperature (-50℃~200℃) conditions.

[0039] See Figure 3 and Figure 4 Both the left cavitation generating plate 18 and the right cavitation generating plate 19 are disc-shaped and centrally symmetrical. The side closer to the part to be processed 5 is defined as the inner side, and the side farther away from the part to be processed 5 is defined as the outer side. Multiple cavitation generating channels are opened in the center of both the left cavitation generating plate 18 and the right cavitation generating plate 19, and the multiple cavitation generating channels are directly opposite the positions of the multiple holes on the part to be processed 5. Each cavitation generation channel is designed with reference to the cavitation nozzle and consists of three sequentially connected parts: an inlet 30, a throat 31, and an outlet 32. The inlet 30 is the channel through which high-pressure fluid enters the cavitation generation channel, and its shape and size affect the initial flow state of the fluid. The throat 31 is the key part of the channel, where the fluid accelerates and forms a low-pressure area, thereby triggering cavitation, i.e., the generation and collapse of cavitation bubbles. The outlet 32 ​​determines the final shape and direction of the jet, and its design affects the distribution of cavitation bubbles and the impact force of the jet. These three parts work together to enable the cavitation generation channel to effectively generate a cavitation jet with strong impact force and erosion ability. The inlet 30 is located on the outer side away from the workpiece 5 and is a cylindrical hole. When the atomizing film is compressed inward, the squeezed liquid enters the left and right cavitation generation plates 18 and 19 from the inlet 30. The inner diameter of the throat 31 is smaller than that of the inlet 30, thus narrowing the channel and constricting it into a smaller diameter channel. The liquid squeezed into the left and right cavitation generating plates 18 and 19 accelerates here and forms a low-pressure area, thereby triggering the cavitation effect. Further inward, the inner diameter of the outlet 32 ​​gradually increases, and the jet with formed cavitation bubbles enters the workpiece 5 to be processed, impacting and strengthening the interior of the workpiece. Preferably, the maximum inner diameter of the outlet 32 ​​is equal to the corresponding aperture of the workpiece 5. Enlarging the opening at the outlet 32 ​​can also reduce the wear of abrasive particles on the cavitation channel. On the inner wall of the throat 31 of the left and right cavitation generating plates 18 and 19, along the axial direction of the throat 31, a throat spiral guide groove 28 is precisely machined. The throat spiral guide groove 28 is evenly distributed circumferentially along the inner wall, with a lead angle of 45°-60°, a groove depth of 2mm, and a groove width of 2mm.

[0040] See Figure 5On the inner wall of the conical section of the left cylinder 1 and the right cylinder 3, there are precision machined cylinder spiral guide grooves 29. The cylinder spiral guide grooves 29 are evenly distributed circumferentially along the inner wall of the cylinder and extend spirally along the axial direction. The lead angle of the cylinder spiral guide grooves 29 is 45°-60°, the groove depth is 2mm, and the width is 50mm.

[0041] Under the action of the cylinder block spiral guide groove 29 and the throat spiral guide groove 28, the axial flow of the liquid generates a viscous shear guiding effect. When the fluid passes through the groove area, the liquid flow near the wall is constrained by the groove inclination angle and changes its momentum direction, while the fluid in the central area maintains axial inertial motion, thus naturally inducing a circumferential velocity component and forming a strong swirling flow field without additional power input. The swirling flow generated by the spiral guide groove has a significant centrifugal effect. The high-speed rotating liquid forms a pressure gradient in the radial direction, and the near-wall area generates a strong centrifugal force due to the small radius of rotation, forcing abrasive particles with a density greater than that of the liquid to migrate towards the cavity wall. At the same time, the low-pressure area at the center of the swirling flow and the high-pressure area on the wall form a pressure difference driving force, causing the main body of the liquid flow to move closely against the wall. This effect not only eliminates the dead zone of abrasive particle settling, but also makes the abrasive particles closely contact the inner wall of the workpiece during the impact stage.

[0042] See Figure 6 When the high-pressure water flow passes through the cylinder spiral guide groove 29 on the inner wall of the cylinder, it is forcibly converted into a high-speed vortex. After entering the spiral guide groove 28 channel of the throat of the left and right cavitation generating plates 18 and 19, this vortex forms a momentum superposition effect due to the consistent direction of rotation, giving the liquid continuously enhanced rotational kinetic energy. The double spiral structure works together to deliver the water flow in a stable rotating state through the interior of the part to be processed 5, achieving two major breakthroughs: First, the rotating flow field covers the entire area: the vortex forms a uniform centrifugal force field inside the part, forcing the abrasive particles to overcome gravity and disperse to the outer edge, completely solving the problem of settling to the bottom and ensuring that the abrasive particles are evenly distributed along the circumference of the pipe wall; Second, the bubbles actively approach the wall surface: the centrifugal force synchronously drives the cavitation bubbles to migrate and gather to the outer edge of the vortex (i.e., the pipe wall), so that the cavitation collapse energy is precisely focused on the pollutants on the wall surface. At the same time, the spiral flow continuously shears the bubble group, promotes the proliferation of microbubbles and inhibits their merging, greatly improving the cavitation density and collapse uniformity. This rotating, through-flow field design, through the directional control of energy and matter via a double-helix structure, ultimately achieves zero abrasive sedimentation, bubble collapse against the wall, and a simultaneous leap in cleaning efficiency and uniformity.

[0043] See Figure 7In the strong swirling flow field induced by the double-helix structure of the cylinder spiral guide groove 29 and the throat spiral guide groove 28, centrifugal force drives abrasive particles and cavitation bubbles to continuously accumulate towards the pipe wall, forming a high-concentration zone on the wall surface (dense near the wall), while the particle distribution in the central region of the pipe is significantly sparse. This directional enrichment effect enables efficient energy focusing: cavitation bubbles collapse close to the wall surface to generate local high-pressure micro-jet, while the synchronously activated abrasive particles perform high-frequency micro-cutting on the surface. The two work together to form an energy-dense layer in the near-wall region, completely avoiding energy dissipation in the central flow field, ultimately improving the pipe wall polishing efficiency and surface roughness uniformity.

[0044] See Figure 1-5 The specific strengthening process of the composite polishing device for strengthening the inner surface of porous parts according to the present invention is as follows:

[0045] Step 1: In a preferred embodiment of the present invention, the channel holes on the left and right cavitation generating plates 18 and 19 are set one-to-one with the hole distribution of the part to be processed 5. Through this correspondence, the jet formed through the cavitation generating channel can accurately enter the inner wall of each channel of the part to be processed 5, thereby ensuring the uniformity and consistency of the strengthening effect. When it is necessary to process parts with different hole types or hole distributions, it is only necessary to re-process the corresponding cavitation generating plate according to the geometric characteristics of the part and replace it during assembly to achieve rapid adaptation. This design avoids the repeated investment of developing a complete set of devices for each type of part, significantly reducing manufacturing and usage costs. At the same time, since the cavitation generating plate adopts a modular and quick-release structure, the replacement process is convenient and does not require modification of the main structure, enabling flexible application in the processing of multi-variety, small-batch, or customized parts. Through the above design, the present invention maintains the efficient cavitation strengthening effect while also being low-cost, scalable, and universal, significantly improving the engineering application value of the device.

[0046] Sealing gaskets 23 and 24 are placed on the flange ends of the left and right cavitation generating plates 18 and 19, respectively. The left and right cavitation generating plates 18 and 19 are then installed and fixed with bolts and elastic washers. At the same time, according to the axial length of the part to be processed 5, the right bracket 15 is adjusted along the guide rail 17, thereby adjusting the distance between the left cylinder 1 and the right cylinder 3 so that the distance is consistent with the length of the part to be processed 5. The part to be processed 5 is then connected to the rubber rings 25 at both ends, the left and right cavitation generating plates 18 and 19, and the left and right cylinders 1 and 3 to form a sealed chamber. This ensures that after the part to be processed 5 is inserted, both ends can fit tightly with the left and right cavitation generating plates 18 and 19 to prevent leakage of the chamber.

[0047] Step 2: Simultaneously open both left and right solenoid valves, injecting purified water and abrasive particles into the left cylinder 1 and right cylinder 3 through the left water injection pipe 7 and right water injection pipe 9. This fills the sealed space formed by the left cylinder 1, the inner cavity of the part to be processed 5, and the right cylinder 3 with water and abrasive particles. Upon entry, the liquid is constrained by the spiral guide grooves, generating initial swirling flow, which promotes uniform dispersion and suspension of the abrasive particles, preventing sedimentation. Close the valves when the inner cavity of the part and the cylinder cavity are completely filled with liquid.

[0048] Step 3: The two external drive motors 26 operate simultaneously, causing the left atomizing film 2 and the right atomizing film 4 to vibrate in opposite directions at the same frequency. This drives the left and right vibrating films to drum-like vibrate at the set frequency and phase. When the two films move towards each other, the cavity generates significant volume alternation, triggering large-amplitude pressure fluctuations; when the two films move in opposite directions, the cavity generates a high-frequency acoustic pressure field, activating the micro-gas nuclei pre-existing in the liquid. The liquid accelerates at the throat 31 of the cavitation generating plate, forming a low-pressure zone, and a large number of cavitation bubbles are activated and enter the cavity of the part to be processed 5.

[0049] Within the five cavities of the workpiece to be processed, cavitation bubbles are driven to migrate toward the inner wall by the centrifugal force of the swirling flow, and rapidly collapse during the high-pressure stage, releasing local high-pressure impact and micro-jet. At the same time, abrasive grains are pressed toward the wall by the swirling flow, and superimposed with the cavitation impact on the inner surface, forming a composite action layer of "bubble collapse impact + abrasive micro-cutting", achieving a synergistic effect of inner wall polishing and strengthening.

[0050] Step 4: After processing, open the outlet solenoid valve to quickly discharge the liquid and abrasive particles from the cavity. The two spiral guide grooves generate a self-cleaning effect during the drainage process, significantly reducing abrasive particle residue and ensuring the long-term stable operation of the device.

[0051] Step 5: Replace the part to be processed 5 with the left and right cavitation generating plates 18 and 19: When processing parts of different specifications or hole distributions, loosen the long bolt 22 and remove the processed part; simultaneously replace the cavitation generating plate with the corresponding design, ensuring that its cavitation channel corresponds one-to-one with the hole channel of the new part. Insert the new part into the left and right rubber rings in sequence and clamp it to complete the reassembly. Through this modular replacement method, various parts can be adapted without modifying the main structure, which reduces manufacturing and maintenance costs and significantly improves the application flexibility of the device.

[0052] Within the five cavities of the workpiece, under the alternating volumetric action generated by diaphragm vibration, the liquid periodically bulges and concaves through the cavitation generation plate channel. With each stretching, the cavity pressure decreases exponentially. According to the ideal gas law PV=nRT, under the isothermal assumption, the pressure reduction is equivalent to a relative increase in the liquid's saturated vapor pressure, creating more favorable conditions for cavitation. Simultaneously, significant turbulence is generated as the liquid enters the cavitation generation channel, exacerbating pressure fluctuations and promoting the generation of more microbubbles. During compression, the liquid is forced into the cavitation generation channel and enters the conical converging inlet. According to the continuity equation and Bernoulli's principle, the flow velocity surges, forming a high-speed jet core region. The spiral guide groove pre-modulated swirling structure optimizes the flow field within the channel, reducing the boundary layer thickness by up to 40% with the tangential velocity component, expanding the low-pressure vortex core region, and increasing the gas core activation efficiency to 92%. Activated bubbles are accelerated through the throat and enter the expansion section, where they collapse together with the original cavitation bubbles within the workpiece cavity. The swirling flow carries abrasive particles that adhere tightly to the cavity wall due to centrifugal effect, improving the impact energy transfer efficiency by 25%. In the boundary layer separation zone, the local static pressure rapidly drops to the liquid saturated vapor pressure, and a large amount of dissolved gas is released to form primary bubbles, which then accelerate into the outlet. The energy released during collapse works synergistically with the abrasive cutting effect to achieve efficient impact strengthening of the inner wall of the part cavity.

[0053] This invention employs a modular and maintainable design, significantly reducing long-term operating costs. For routine maintenance: the left cavitation generating plate 18 and right cavitation generating plate 19, along with the left sealing gasket 23 and right sealing gasket 24, are designed with quick-release structures, allowing replacement simply by unscrewing the bolts without the need for special tools. After every 100-hour operating cycle, the throat area of ​​the left cavitation generating plate 18 and right cavitation generating plate 19 is deeply cleaned using an ultrasonic cleaner (frequency 40kHz) to remove abrasive residues and cavitation debris, ensuring smooth jet flow. For critical component life management: the elastic gasket uses fatigue-resistant materials, such as a fluororubber-metal composite layer, and is replaced every 500 hours or when significant deformation occurs; the sealing gasket is equipped with wear indicators (such as a color-gradient coating), and must be replaced immediately when the coating completely fades.

Claims

1. A method for strengthening the inner surface of porous parts through high-efficiency composite polishing, comprising a device for strengthening the inner surface of porous parts through high-efficiency composite polishing, comprising a left cylinder (1) and a right cylinder (3) with identical structure and symmetrical arrangement, wherein each of the left cylinder (1) and the right cylinder (3) has a cylinder inlet at its top, a left atomizing film (2) is sealed to the left end of the left cylinder (1), and a right atomizing film (4) is sealed to the right end of the right cylinder (3), and a drive motor (26) is attached to the outer side of each of the left atomizing film (2) and the right atomizing film (4); the inner diameter of the left cylinder (1) and the right cylinder (3) gradually decreases from the middle to the inner end, forming a cone, wherein a cylinder spiral guide groove (29) is provided on the inner wall of the cone, which is uniformly distributed along the circumference of the inner wall of the cylinder and spirally extended along the axial direction; the right end of the left cylinder (1) is sealed to the left cavitation generating plate (18), and the left end of the right cylinder (3) is sealed to the right cavitation generating plate (19), and the left cavitation generating plate (19) is sealed to the right cavitation generating plate (19). The left cavitation generating plate (18) and the right cavitation generating plate (19) have the same structure and are arranged symmetrically on the left and right sides. The horizontally placed part to be processed (5) is a porous part, which is fixed and pressed between the left cavitation generating plate (18) and the right cavitation generating plate (19) by rubber rings (25). The center of the left cavitation generating plate (18) and the right cavitation generating plate (19) has multiple cavitation generating channels, and the multiple cavitation generating channels are directly opposite to the porous positions on the part to be processed (5). Each cavitation generating channel... The chemical generation channel consists of an inlet (30), a throat (31), and an outlet (32) connected in sequence. The inlet (30) is located on the outer side away from the workpiece (5) and is a cylindrical hole. The inner diameter of the throat (31) is smaller than the inner diameter of the inlet (30), and the inner diameter of the outlet (32) gradually increases. The inner wall of the throat (31) is provided with a throat spiral guide groove (28) that is evenly distributed along the circumference of the inner wall of the throat (31) and spirally extended along the axial direction. Its characteristic is that... Includes the following steps: Step 1): Pure water and abrasive particles are injected into the left cylinder (1) and right cylinder (3) simultaneously through the water inlet, so that the closed space formed by the left cylinder (1), the inner cavity of the part to be processed (5) and the right cylinder (3) is filled with water and abrasive particles. After the liquid enters, it is constrained by the spiral guide groove to generate an initial vortex, which promotes the uniform dispersion and suspension of the abrasive particles. Step 2): Two drive motors (26) work simultaneously, causing the left atomizing film (2) and the right atomizing film (4) to vibrate towards each other at the same frequency. When the two films move towards each other, the cavity generates volume alternation. When the two films move in opposite directions, the cavity generates a high-frequency acoustic pressure field. The liquid is accelerated at the throat (31) to form a low-pressure area. Cavitation bubbles are activated and enter the cavity of the part to be processed (5) to achieve inner wall polishing and strengthening. Step 3): After processing, replace the part to be processed (5) with the left and right cavitation generating plates (18, 19); when it is necessary to process parts of different specifications or hole distribution, remove the processed parts and replace the left and right cavitation generating plates (18, 19) with the corresponding designs, so that the cavitation channels of the left and right cavitation generating plates (18, 19) correspond one-to-one with the holes of the new parts.

2. The method for strengthening the inner surface of porous parts through high-efficiency composite polishing according to claim 1, characterized in that: A cylinder outlet is opened at the bottom of the left cylinder (1) and the right cylinder (3). A solenoid valve is provided at the cylinder outlet. A pressure sensor is provided in the left cylinder (1) and the right cylinder (3) to monitor the pressure in real time. When the pressure exceeds the preset threshold or pressure oscillation is detected, the solenoid valve opens to release pressure at the same time.

3. The method for high-efficiency composite polishing to strengthen the inner surface of porous parts according to claim 1, characterized in that: The left atomizing film (2) and the right atomizing film (4) can complete one displacement cycle in milliseconds or microseconds, and the driving frequency covers the range of tens of hertz to tens of kilohertz.

4. The method for strengthening the inner surface of porous parts through high-efficiency composite polishing according to claim 1, characterized in that: The cylinder of the left cylinder (1) is fixed on the horizontally arranged base (16) by the left bracket (14). The right cylinder (3) is fixedly connected to the right bracket (15) which can move horizontally left and right. The right bracket (15) is connected to the base (16). The base (16) is provided with a guide rail (17). The guide rail (17) consists of two T-shaped bosses. The length direction of the T-shaped bosses is consistent with the central axis direction of the right cylinder (3). The bottom end of the right bracket (15) is provided with two T-shaped grooves. The two T-shaped bosses and the two T-shaped grooves cooperate with each other.

5. The method for efficiently strengthening the inner surface of porous parts through composite polishing according to claim 1, characterized in that: The left cylinder (1) and the right cylinder (3) have flanges on the inner side near the workpiece (5). The flanges have through holes and are connected by bolts on the upper and lower sides respectively. The left cavitation generating plate (18) and the right cavitation generating plate (19) are fixed on the corresponding left cylinder (1) and right cylinder (3) respectively.

6. The method for strengthening the inner surface of porous parts through high-efficiency composite polishing according to claim 1, characterized in that: The maximum inner diameter of the outlet (32) is equal to the diameter of the corresponding part to be processed (5).

7. The method for strengthening the inner surface of porous parts through high-efficiency composite polishing according to claim 1, characterized in that: The throat spiral guide groove (28) has a lead angle of 45°-60°, a groove depth of 2mm, and a groove width of 2mm.

8. The method for strengthening the inner surface of porous parts through high-efficiency composite polishing according to claim 1, characterized in that: The lead angle of the cylinder block spiral guide groove (29) is 45°-60°, the groove depth is 2mm, and the width is 50mm.

9. The method for strengthening the inner surface of porous parts through high-efficiency composite polishing according to claim 1, characterized in that: The cylinder inlet is equipped with a solenoid valve to control its opening and closing, and a water injection pipe is connected above the cylinder inlet.

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