Multi-stage cavitation jet injection device

Abstract

The invention provides a multi-stage cavitation jet jetting device. The multi-stage cavitation jet jetting device comprises an inlet pipe, a first connecting pipe, an upstream nozzle, a second connecting pipe and a downstream nozzle. The inlet pipe is connected with the first connecting pipe, and the upstream nozzle is arranged at the joint of the inlet pipe and the first connecting pipe; the first connecting pipe is connected with the second connecting pipe, an inner cavity of the first connecting pipe is communicated with an inner cavity of the second connecting pipe, and a Helmholtz resonant cavity is formed by the first connecting pipe and the second connecting pipe; the downstream nozzle is arranged at the downstream end of the second connecting pipe; fluid sequentially flows through the inlet pipe, the upstream nozzle, the Helmholtz resonant cavity and the downstream nozzle and then is sprayed out; an organ pipe cavity structure used for inducing self-oscillation of fluid is arranged in the downstream nozzle. The problems that an existing cavitation nozzle is complex in internal structure, large in machining difficulty and high in manufacturing cost are solved, and the problems that a single cavitation mechanism adopted in the prior art is insufficient in cavitation strength and efficiency are solved.

Description

Technical Field

[0001] This invention relates to the field of cavitation jet technology, and more specifically to a multi-stage cavitation jet injection device. Background Technology

[0002] Water jet surface strengthening and cleaning technology is widely used in aerospace, marine engineering, and machinery manufacturing due to its advantages such as being environmentally friendly and having no heat-affected zone. Among them, cavitation water jetting utilizes high-speed water flow to generate cavitation bubbles in a local low-pressure area. The micro-jet and shock wave generated when the cavitation bubbles collapse peel off dirt or strengthen metal surfaces. Compared with traditional continuous water jetting, it has the significant advantages of low energy consumption and high efficiency.

[0003] The nozzle is the core component for generating cavitation jets. Existing cavitation nozzles mainly rely on a single principle design, such as simple shear nozzles or bellows nozzles, which have limited cavitation intensity and cannot meet the needs of high-intensity cleaning or deep surface strengthening. In order to improve the cavitation effect, the industry has begun to study composite nozzles that combine different cavitation principles, such as nozzles that combine Helmholtz resonant cavities with self-excited oscillation principles.

[0004] However, existing composite cavitation nozzles typically employ a one-piece integrated design. This design has the following significant drawbacks: 1. Extremely difficult to manufacture: To form an effective Helmholtz resonant cavity or bellows-like structure, complex irregularly shaped internal flow channels with specific expansion-contraction ratios need to be machined inside the nozzle. In a one-piece structure, these cavities are often deeply embedded within the workpiece, making them difficult for cutting tools to access. This necessitates extremely high machining precision and process requirements, resulting in high manufacturing costs and difficulty in ensuring the surface finish of the flow channels, thus increasing frictional resistance and affecting jet performance. 2. Fixed and unadjustable structure: Once the one-piece nozzle is manufactured, the natural frequency of its resonant cavity is fixed. It is impossible to fine-tune the cavity structure to match the optimal resonant frequency according to different operating conditions (such as changes in pump pressure or target distance), limiting the equipment's versatility and operational efficiency. 3. Difficult maintenance: The nozzle interior is a vulnerable part. Once wear or blockage occurs inside the one-piece structure, it often has to be scrapped entirely, resulting in high maintenance costs. Summary of the Invention

[0005] This invention provides a multi-stage cavitation jet injection device to solve the problems of complex internal structure, high processing difficulty and high manufacturing cost of existing cavitation nozzles, as well as the problem of insufficient cavitation intensity and efficiency of the single cavitation mechanism used in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A multi-stage cavitation jet injection device, the multi-stage cavitation jet injection device comprising an inlet pipe, a first connecting pipe, an upstream nozzle, a second connecting pipe, and a downstream nozzle; The downstream end of the inlet pipe is connected to the upstream end of the first connecting pipe, and the upstream nozzle is located at the connection between the two. The downstream end of the first connecting tube is connected to the upstream end of the second connecting tube, and the internal cavity of the first connecting tube is connected to the internal cavity of the second connecting tube, together forming a Helmholtz resonant cavity. The downstream nozzle is located at the downstream end of the second connecting pipe; The fluid flows sequentially through the inlet pipe, the upstream nozzle, the Helmholtz resonant cavity, and the downstream nozzle before being ejected. The downstream nozzle is equipped with an organ-shaped cavity structure for inducing fluid self-excited oscillation.

[0007] Compared with the prior art, the present invention has achieved the following beneficial effects: 1. At the structural level, it reduces processing difficulty and significantly saves costs: The present invention adopts a "split assembly" structure. The Helmholtz resonant cavity is not machined as a whole on a single part, but is formed by connecting the first connecting pipe and the second connecting pipe. This means that the complex internal cavity machining can be decomposed into the machining of two relatively simple inner holes of the pipes, avoiding the difficulties of deep hole machining and complex cavity forming, and significantly reducing the requirements for processing equipment and manufacturing costs.

[0008] 2. In principle, multi-level coupling enhances the cavitation effect: The device provided by this invention constructs a multi-stage cascading cavitation system consisting of "upstream nozzle (shearing) - Helmholtz resonant cavity (resonance) - downstream organ pipe nozzle (self-excited oscillation)". The fluid successively experiences high-speed shearing, acoustic resonance amplification in the cavity, and self-excited oscillation pulse at the outlet. The superposition of these three physical effects significantly increases the amount of cavitation bubbles generated and the collapse intensity. Compared with a single-mechanism nozzle, its cleaning or stripping efficiency is qualitatively improved.

[0009] 3. From a fluid dynamics perspective, it is conducive to cavitation development and transport: The multi-stage segmented flow channel design, especially the resonant cavity in the middle, helps maintain the flow field environment inside the pipe, prolongs the time for cavitation bubble nucleation and development, and allows the bubbles to grow to the ideal size before reaching the surface being cleaned, thereby releasing more energy when they collapse. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a schematic diagram of the structure of the multi-stage cavitation jet injection device provided in the first embodiment of the present invention; Figure 2 yes Figure 1 A schematic diagram of the jetting device from another viewing angle; Figure 3 yes Figure 2 Sectional view along AA; Figure 4 This is a schematic diagram of the multi-stage cavitation jet injection device provided in the second embodiment of the present invention when applied to a thin plate; Figure 5 This is a volumetric cloud map of cavitation bubbles; Figure 6 The images show the microstructure of the metal scrap before cleaning and the microstructure after cleaning by the multi-stage cavitation jet spraying device provided by this invention. Figure 7(a) is a schematic diagram of the structure of the second connecting pipe provided in the third embodiment of the present invention; Figure 7(b) is a cross-sectional view of the second connecting pipe along BB in Figure 7(a); Figure 8 This is a cross-sectional view of the organ pipe provided in the fourth embodiment of the present invention.

[0012] Explanation of reference numerals in the attached figures 1-Inlet; 2-Inlet pipe; 3-Inlet throat flow channel; 4-First connecting pipe; 41-Converging inlet section; 42-Throat flow channel; 43-Gradually widening outlet section; 5-Inlet widening cavity; 6-Helmholtz resonant cavity inlet; 7-Second connecting pipe; 71-Converging section; 72-Throat flow channel; 73-Gradually widening section; 8-Helmholtz resonant cavity; 9-Helmholtz resonant cavity outlet; 10-Angle structure cavity; 11-Locking nut; 12-Locking sleeve; 13-Downstream nozzle; 14-Bugler tube cavity inlet; 15-Bugler tube cavity contraction section; 16-Bugler tube nozzle throat flow channel; 17-Gradually widening nozzle outlet. Detailed Implementation

[0013] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It should be understood that the specific embodiments described herein are only for illustration and explanation of the present invention and are not intended to limit the present invention.

[0014] Any specific numerical values ​​disclosed herein (including the endpoints of numerical ranges) are not limited to their exact values, but should be understood to also include values ​​close to the exact value, such as all possible values ​​within ±5% of the exact value. Furthermore, with respect to the disclosed numerical ranges, one or more new numerical ranges can be obtained by arbitrarily combining the endpoint values ​​of the range, the endpoint values ​​with specific point values ​​within the range, and the specific point values ​​themselves; these new numerical ranges should also be considered as specifically disclosed herein.

[0015] The terminology used in this invention is for the purpose of describing specific exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” as used herein are intended to include the plural forms as well. The terms “comprising,” “including,” “containing,” and “having” are inclusive and thus describe the presence of said features, elements, compositions, steps, integers, operations, and / or components, but do not exclude the presence or inclusion of one or more other features, integers, steps, operations, elements, components, and / or sets thereof. Although the open-ended term “comprising” should be understood as a non-limiting term used to describe and claim the various embodiments described in this invention, in some aspects it may instead be understood as a more restrictive and limiting term, such as “consisting of” or “essentially composed of.” Thus, for any given embodiment describing a composition, material, component, element, feature, integer, operation, and / or process step, the invention also particularly includes embodiments consisting of or substantially consisting of such compositions, materials, components, elements, features, integers, operations, and / or process steps. In the case of “consisting of…”, the alternative embodiments exclude any additional compositions, materials, components, elements, features, integers, operations and / or process steps. In the case of “essentially composed of…”, any additional compositions, materials, components, elements, features, integers, operations and / or process steps that substantially affect the essential and novel characteristics are excluded from such embodiments. However, any compositions, materials, components, elements, features, integers, operations and / or process steps that do not substantially affect the essential and novel characteristics may be included in the embodiments.

[0016] Any method steps, processes, and operations described in this invention should not be construed as necessarily requiring them to be performed in the specific order discussed or shown, unless explicitly specified. It should also be understood that, unless otherwise stated, additional or alternative steps may be used.

[0017] In this invention, except where expressly stated, any matters or issues not mentioned are directly applicable to those known in the art without any modification. Furthermore, any embodiment described in this invention can be freely combined with one or more other embodiments described in this invention, and the resulting technical solutions or concepts are considered part of the original disclosure or original record of this invention, and should not be regarded as new content not disclosed or anticipated by this invention, unless those skilled in the art consider the combination to be clearly unreasonable.

[0018] Unless otherwise stated, the terms used herein have the same meaning as commonly understood by those skilled in the art, and if a term is defined herein and its definition differs from the common understanding in the art, the definition herein shall prevail.

[0019] like Figures 1 to 3 As shown, the present invention provides a multi-stage cavitation jet injection device, which includes an inlet pipe 2, a first connecting pipe 4, an upstream nozzle, a second connecting pipe 7, and a downstream nozzle 13. The downstream end of the inlet pipe 2 is connected to the upstream end of the first connecting pipe 4, and the upstream nozzle is located at the connection between the two. The downstream end of the first connecting pipe 4 is connected to the upstream end of the second connecting pipe 7, and the internal cavity of the first connecting pipe 4 is connected to the internal cavity of the second connecting pipe 7, forming a Helmholtz resonant cavity 8 together. The downstream nozzle 13 is located at the downstream end of the second connecting pipe 7. The fluid flows sequentially through the inlet pipe 2, the upstream nozzle, the Helmholtz resonant cavity 8, and the downstream nozzle 13 before being ejected. The downstream nozzle 13 has an organ-shaped cavity structure inside for inducing self-excited oscillation of the fluid. This invention adopts a split structure, designing the Helmholtz resonant cavity 8 as "formed by the first connecting pipe 4 and the second connecting pipe 7 together", which significantly reduces the difficulty of deep hole processing and irregular internal cavity forming, and facilitates processing, manufacturing and assembly. At the same time, the device constructs a multi-stage interlocking cavitation system of "upstream shearing - midstream resonant amplification - downstream self-excited oscillation". The fluid first undergoes high-speed shearing through the upstream nozzle, and after entering the Helmholtz resonant cavity 8, the pressure pulsation is further amplified by acoustic resonance. Finally, the strong self-excited oscillation is induced by the bellows structure inside the downstream nozzle 13. The three physical effects are coupled and superimposed, which greatly increases the amount of cavitation bubbles generated and extends the bubble growth time by using multi-stage flow channels. This solves the problems of high processing difficulty and high manufacturing cost of irregular internal flow channels in the integral composite cavitation nozzle in the prior art, as well as the limited cavitation intensity of single-mechanism nozzles, which is difficult to meet the requirements of efficient cleaning or deep surface strengthening.

[0020] See Figure 3 In some embodiments of the present invention, the outlet of the upstream nozzle extends into the interior of the Helmholtz resonant cavity 8, or the outlet of the upstream nozzle is connected to the interior of the Helmholtz resonant cavity 8.

[0021] See Figure 3 In some embodiments of the present invention, the upstream end of the second connecting pipe 7 is inserted into the first connecting pipe 4, and the two together form the Helmholtz resonant cavity 8. In some embodiments of the present invention, the downstream nozzle 13 described above may be a sand pipe or a sand mixing nozzle.

[0022] In some embodiments of the present invention, the first connecting tube 4 is a tube with a flared inner cavity, and the second connecting tube 7 is a tube with a protruding end, thereby constructing a Helmholtz resonant cavity 8, which also facilitates the modular design and identification assembly of components.

[0023] In some embodiments of the present invention, the first connecting pipe 4 is a Helmholtz connecting pipe, and the second connecting pipe 7 is an angle connecting pipe. The first connecting pipe 4 is configured as a Helmholtz connecting pipe, and the second connecting pipe 7 is configured as an angle connecting pipe, thereby constructing a Helmholtz resonant cavity 8, which facilitates the modular design and identification assembly of components. At the same time, this also solves the problem of the lack of standardized definition when connecting pipes are adapted to specific flow channel geometry features.

[0024] See Figure 3 The flow channel inside the second connecting pipe 7 is the angular structure cavity 10.

[0025] In some embodiments of the present invention, the first connecting pipe 4 and the second connecting pipe 7 are connected by threads. Fixing the first connecting pipe 4 and the second connecting pipe 7 by threads not only withstands the axial impact force generated by the high-pressure water jet to ensure structural safety, but also achieves the device's detachability, facilitating maintenance, cleaning, or replacement of damaged components within the internal cavity. This solves the problem that existing connection methods are either non-detachable or lack sufficient connection strength to withstand high pressure, making it difficult to maintain or replace vulnerable internal parts.

[0026] In some embodiments of the present invention, the threaded connection depth between the first connecting pipe 4 and the second connecting pipe 7 is adjustable, and the cavity length of the Helmholtz resonant cavity 8 is adjusted by changing the thread engagement depth. By configuring the threaded connection depth between the first connecting pipe 4 and the second connecting pipe 7 to be adjustable, the cavity length of the Helmholtz resonant cavity 8 can be changed, thereby adjusting the inherent acoustic frequency of the resonant cavity. This allows it to resonate with the self-excited oscillation frequency of the jet through a "frequency-locking" effect, ensuring that the maximum pressure pulsation can be obtained under different operating conditions. This solves the problem that a fixed-structure resonant cavity has a single inherent frequency, which cannot adapt to the optimal resonance requirements under different operating conditions such as pump pressure and flow rate changes, resulting in the cavitation effect not always remaining at its peak.

[0027] It should be noted that in some embodiments of the present invention, the above-mentioned adjustment operation is performed between the first connecting pipe 4 and the second connecting pipe 7, and does not involve the inlet pipe 2.

[0028] like Figure 3 As shown, in some embodiments of the present invention, the upstream end of the second connecting pipe 7 has a protruding structure that protrudes into the first connecting pipe 4. The outer wall of the protruding structure cooperates with the inner wall of the first connecting pipe 4 to form the cavity space of the Helmholtz resonant cavity 8. Utilizing the "insertion-type" assembly principle, the protruding structure at the upstream end of the second connecting pipe 7 is cleverly used to cooperate with the inner wall of the first connecting pipe 4, automatically forming the neck required for the Helmholtz resonant cavity 8. This design completely avoids the difficulty of machining complex chamfers and necks deep inside the pipe, transforming the inner cavity forming into the more controllable outer wall machining. This solves the problem of numerous machining blind spots and extremely difficult precision assurance when machining the "neck" required for the Helmholtz resonant cavity in integrated or traditional pipe fittings.

[0029] See Figure 3 In some embodiments of the present invention, the Helmholtz resonant cavity inlet 6 is formed at the connection between the upstream nozzle outlet and the Helmholtz resonant cavity 8, where the fluid undergoes a sudden cross-sectional expansion, causing pressure waves to be reflected. The Helmholtz resonant cavity outlet 9 is formed on the central axis of the protruding structure at the upstream end of the second connecting pipe 7, constituting the cavity space of the Helmholtz resonator. The cross-sectional area of ​​the flow channel at the Helmholtz resonant cavity outlet 9 is much smaller than that of the Helmholtz resonant cavity 8. This cross-sectional contraction structure causes a flow resistance effect when the fluid flows through this area, which, together with the volume effect of the Helmholtz resonant cavity 8, determines the natural frequency of the resonant cavity. When the fluid flows through the inlet 6 and outlet 9, due to the discontinuity of acoustic impedance, the pressure wave reflects back and forth within the cavity and forms a standing wave, thereby enhancing the cavitation effect.

[0030] As shown in Figures 7(a) and 7(b), in some embodiments of the present invention, the second connecting pipe 7 is provided with a tapered section 71, a throat channel 72, and a widening section 73 arranged sequentially along the fluid flow direction. The tapered section 71 is located inside the protruding structure. It should be noted that the streamlined flow channel with tapered section 71, throat channel 72, and widening section 73 inside the second connecting pipe 7 (especially inside the protruding structure) can effectively rectify the flow and reduce hydraulic losses along the flow path. It can also accelerate and stabilize the fluid again using the Venturi effect, providing an ideal initial velocity field and pressure field for the fluid to enter the downstream nozzle 13. This solves the problem of "excessive local resistance loss caused by abrupt changes in the flow channel when the fluid enters the downstream flow channel from the resonant cavity, resulting in severe attenuation of jet energy".

[0031] like Figure 3As shown, in some embodiments of the present invention, the spraying device further includes a locking device; the downstream nozzle 13 is fixed to the downstream end of the second connecting pipe 7 by the locking device; the locking device includes a locking nut 11 and a locking sleeve 12, the locking sleeve 12 is sleeved on the outer periphery of the downstream nozzle 13, and the locking nut 11 is threadedly connected to the second connecting pipe 7 to press the locking sleeve 12. By using the structure of the locking nut 11 and the locking sleeve 12, the radial clamping force generated by the locking sleeve 12 firmly fixes the downstream nozzle 13, which can prevent axial movement under high pressure and allows for quick disassembly and assembly when the nozzle needs to be replaced due to wear, thereby solving the problem that the downstream nozzle 13, as a vulnerable part, needs frequent replacement under long-term high-pressure erosion, while direct threaded connections are prone to loosening due to vibration or corrosion, making disassembly and maintenance difficult.

[0032] like Figure 8 As shown, in some embodiments of the present invention, the bellows cavity structure sequentially includes a bellows cavity inlet 14, a bellows cavity contraction section 15, a bellows nozzle throat flow channel 16, and a gradually widening nozzle outlet 17 along the fluid flow direction. Utilizing the bellows structure formed by the bellows cavity inlet 14, the bellows cavity contraction section 15, the bellows nozzle throat flow channel 16, and the gradually widening nozzle outlet 17, strong self-excited oscillations are induced by the hydroacoustic characteristics of the fluid, generating transient vortex rings and pressure wave reflections within the cavity. This modulates the continuous jet into a pulsed jet with high-frequency pulsating characteristics, generating extremely high "water hammer pressure" upon impacting the target surface. This solves the problem that ordinary conical nozzles produce jets that are mostly continuous flows, lacking pulse impact force, resulting in limited cavitation cloud development and low cleaning and stripping efficiency.

[0033] like Figure 8 As shown, in some embodiments of the present invention, the inner wall surface of the bellows cavity contraction section 15 is configured as a discontinuous stepped or corrugated structure. Configuring the inner wall surface of the bellows cavity contraction section 15 as a discontinuous stepped or corrugated structure serves as an artificial disturbance source. When high-speed fluid flows through it, it forcibly induces boundary layer separation and shear layer instability, promoting the formation and shedding of large-scale vortex rings. This excites and enhances the self-excited oscillation effect of the jet over a wider flow velocity range, thus solving the problem that smooth contraction walls are difficult to effectively excite boundary layer disturbances, resulting in a high initiation threshold or insufficient oscillation amplitude for self-excited oscillation.

[0034] In some embodiments of the present invention, the upstream nozzle is an independent rigid nozzle core, which is axially pressed and fixed between the end face of the inlet pipe 2 and the stepped surface inside the first connecting pipe 4. Using an independent rigid nozzle core as the upstream nozzle significantly improves the wear resistance and lifespan of the critical throttling element. Simultaneously, the axial pressing and fixing of the nozzle core via the connection structure of the inlet pipe 2 and the first connecting pipe 4 eliminates the need for machining threads on brittle, hard materials, thus protecting the nozzle core and achieving simple installation and positioning. This solves the problem that the upstream nozzle throat is prone to cavitation wear and failure at high flow rates, and that using an integrated machining structure would lead to the scrapping of the entire pipe and extremely high replacement costs.

[0035] In some embodiments of the present invention, the upstream nozzle may be integrally formed with the internal flow cavity of the first connecting pipe 4.

[0036] like Figure 3 As shown in Figure B, in some embodiments of the present invention, the internal flow channel of the upstream nozzle includes a tapered inlet section 41, a throat flow channel 42, and a widening outlet section 43 connected in sequence. The Laval-like flow channel design, comprising the tapered inlet section 41, the throat flow channel 42, and the widening outlet section 43, not only minimizes inlet resistance but also controls the jet diffusion angle and velocity distribution through the widening section. This allows the jet to possess extremely high kinetic energy and an ideal flow state before entering the Helmholtz resonant cavity 8, thereby solving the problems of low flow coefficient and large jet divergence angle in conventional straight-hole nozzles, making it difficult to form a high-energy-density jet to induce subsequent strong shearing and resonance.

[0037] like Figure 3 As shown, in some embodiments of the present invention, the inlet pipe 2 is provided with an inlet throat channel 3 and an inlet protrusion cavity 5 in its internal flow channel; the inlet protrusion cavity 5 is located upstream of the upstream nozzle. The inlet throat channel 3 and the inlet protrusion cavity 5 constitute a pre-positioned rectification and pressure stabilization unit. Before entering the upstream nozzle, the fluid undergoes a preliminary contraction and expansion, which helps to eliminate large-scale vortices in the incoming flow and homogenize the velocity distribution, ensuring the stability of the fluid entering the upstream nozzle. This solves the problem that turbulence, vortices, or pressure fluctuations carried in the incoming liquid interfere with the jet stability of the upstream nozzle, thereby affecting the consistency and repeatability of the cavitation performance of the entire device.

[0038] In some embodiments of the present invention, the outlet of the above-mentioned multi-stage cavitation jet spraying device is submerged in water to a depth of not less than 40 mm, the jet pressure ranges from 30 MPa to 150 MPa, the distance between the spraying device and the surface to be cleaned ranges from 75 mm to 220 mm, and the moving speed of the nozzle does not exceed 1200 mm / min.

[0039] Example 1 The above-mentioned multi-stage cavitation jet spraying device is applied to the surface cleaning of thin metal sheets, such as... Figure 4 As shown. The jetting device provided by this invention can be installed on a three-axis machine tool, machining center or robotic arm. The thin plate workpiece is placed below the downstream nozzle 13, and the jet nozzle moves relative to the thin plate workpiece. By controlling the jet water pressure, nozzle moving speed and jet angle, the multi-media synergistic jet strengthening process can be changed, and the best jet strengthening parameters can be optimized.

[0040] like Figure 4 As shown, in some embodiments, the sheet is conveyed along its length, and the downstream nozzle 13 moves back and forth along the width of the sheet to thoroughly clean the surface of the sheet.

[0041] Example 2 The above-mentioned multi-stage cavitation jet spraying device is applied to the surface cleaning of returned metal scrap, such as... Figure 6 As shown, before cleaning, the surface of the metal scrap was covered with a large number of inclusions and other impurities. However, after being treated by the multi-stage cavitation jet spraying device of this invention under the process conditions of a nozzle submersion depth of 60 mm, a jet pressure of 50 MPa, a moving speed of 800 mm / min, and a target distance of 100 mm, high-performance cleaning of the scrap was achieved. The cleaned surface was free of visible impurities. Figure 6 As shown.

[0042] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims. Furthermore, specific examples have been used in the specification to illustrate the principles and implementation methods of the present invention. The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention, and the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A multi-stage cavitation jet injection device, characterized by, The multi-stage cavitation jet injection device comprises an inlet pipe (2), a first connecting pipe (4), an upstream nozzle, a second connecting pipe (7) and a downstream nozzle (13); The downstream end of the inlet pipe (2) is connected with the upstream end of the first connecting pipe (4), and the upstream nozzle is arranged at the connection position of the two pipes; The downstream end of the first connecting pipe (4) is connected with the upstream end of the second connecting pipe (7), the internal cavity of the first connecting pipe (4) is communicated with the internal cavity of the second connecting pipe (7), and the two cavities jointly form a Helmholtz resonator (8); The downstream nozzle (13) is arranged at the downstream end of the second connecting pipe (7); The fluid flows through the inlet pipe (2), the upstream nozzle, the Helmholtz resonator (8) and the downstream nozzle (13 in sequence and is then sprayed out. The internal cavity of the downstream nozzle (13) is provided with an organ pipe cavity structure for inducing self-excited oscillation of the fluid.

2. The multi-stage cavitation jet injection device of claim 1, wherein, At least one of the following features is provided: The first connecting pipe (4) is a Helmholtz connecting pipe, and the second connecting pipe (7) is an angle connecting pipe; The first connecting pipe (4) and the second connecting pipe (7) are connected through threads; The upstream end of the second connecting pipe (7) has a protruding structure which protrudes into the first connecting pipe (4), and the outer wall of the protruding structure cooperates with the inner wall of the first connecting pipe (4) to form the cavity space of the Helmholtz resonator (8).

3. The multi-stage cavitation jet injection device of claim 2, wherein, The depth of the thread connection between the first connecting pipe (4) and the second connecting pipe (7) is adjustable, and the cavity length of the Helmholtz resonator (8) is adjusted by changing the thread engagement depth.

4. The multi-stage cavitation jet injection device of claim 2, wherein, The second connecting pipe (7) is internally provided with a gradually tapered section (71), a throat flow channel (72) and a gradually widened section (73) which are arranged in sequence along the fluid flow direction, and the gradually tapered section is located in the internal cavity of the protruding structure.

5. The multi-stage cavitation jet injection device of claim 1, wherein, The injection device further comprises a locking device; The downstream nozzle (13) is fixed to the downstream end of the second connecting pipe (7) through the locking device; The locking device comprises a locking nut (11) and a locking sleeve (12), the locking sleeve (12) is sleeved on the outer periphery of the downstream nozzle (13), and the locking nut (11) is threadedly connected with the second connecting pipe (7) to press the locking sleeve (12).

6. The multi-stage cavitation jet injection device of claim 1, wherein, The organ pipe cavity structure comprises an organ pipe cavity inlet (14), an organ pipe cavity contraction section (15), an organ pipe nozzle throat flow channel (16) and a gradually widened nozzle outlet (17) which are arranged in sequence along the fluid flow direction.

7. The multi-stage cavitation jet injection device of claim 6, wherein, The inner wall surface of the organ pipe cavity contraction section (15) is configured as a non-continuous stepped or corrugated structure.

8. The multi-stage cavitation jet injection device of claim 1, wherein, The upstream nozzle is an independent hard nozzle core which is axially pressed and fixed between the end face of the inlet pipe (2) and the stepped face in the internal cavity of the first connecting pipe (4).

9. The multi-stage cavitation jet injection device of claim 8, wherein, The internal flow channel of the upstream nozzle comprises a gradually tapered inlet section (41), a throat flow channel (42) and a gradually widened outlet section (43) which are connected in sequence.

10. The multi-stage cavitation jet injection device of claim 1, wherein, The internal flow channel of the inlet pipe (2) is provided with a water inlet throat flow channel (3) and a water inlet wide protruding cavity (5); The water inlet wide protruding cavity (5) is located on the upstream side of the upstream nozzle.

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