High-strength cavitation nozzle

Abstract

To provide a nozzle improved in cavitation strength.SOLUTION: A cavitation peening device is equipped with a fluid supply source, a conduit, and a portable nozzle assembly. The conduit is equipped with a proximal end portion connected to the fluid supply source, and a distal end portion connected to the portable nozzle assembly. The portable nozzle assembly is equipped with an inner nozzle configured to lead a first flow of a high-pressure fluid, and an outer nozzle configured to lead a second flow of a low-pressure fluid so as to flow coaxially around the first flow. The inner nozzle is equipped with a cavitation insert that has an inner passage including at least two reducing portions in a cross-sectional area.SELECTED DRAWING: Figure 3

Description

[Background technology]

[0001] Improving the surface integrity and smoothing critical surfaces of parts used in aerospace and related industries is of paramount importance for improving their corrosion and fretting fatigue resistance, extending fatigue life, and enabling new additive manufacturing techniques. Cavitation processes, such as cavitation peening (CP) and cavitation abrasive surfacing (CASF), are cheaper, safer, faster, and have a lower environmental impact than previous surface treatment methods. Inexpensive water abrasion and inert polishing can be used instead of expensive and hazardous shot media, chemical cleaners, acids, or powerful laser beams.

[0002] Cavitation processes utilize the impact pressure generated by cavitation bubbles collapsing on a metal surface to induce beneficial compressive residual stresses, energizing abrasive particles to remove material upon impact. One common process configuration involves submerging the part to be treated within a reservoir of fluid. Another configuration involves encapsulating a high-velocity jet within a low-velocity jet. This configuration is known as co-flow due to the coaxiality of the low-velocity and high-velocity streams. Summary of the Invention [Problem to be solved by the invention]

[0003] To reduce processing time and increase throughput for practical applications, a nozzle with increased cavitation intensity would be beneficial. [Means for solving the problem]

[0004] The present disclosure provides systems, devices, and methods related to cavitation peening. In some examples, an apparatus for cavitation peening may include a fluid supply, a conduit, and a portable nozzle assembly. The conduit may have a proximal end connected to the fluid supply and a distal end connected to the portable nozzle assembly. The portable nozzle assembly may include an inner nozzle directing a first flow of high-pressure fluid and an outer nozzle directing a second flow of low-pressure fluid coaxially around the first flow. The inner nozzle may include a cavitation insert having an inner passage including at least two reductions in cross-sectional area.

[0005] In some examples, a cavitation peening nozzle may include a cylindrical tube and an organ tube cavitator at the distal end of the tube that delivers a cavitating jet of high-pressure fluid. The cavitator's inner passage may have a proximal portion, an intermediate portion, and a distal portion. The proximal portion may have a first inner diameter, the intermediate portion may have a second inner diameter, and the distal portion may have a third inner diameter. The first inner diameter may be larger than the second inner diameter, and the second inner diameter may be larger than the third inner diameter.

[0006] In some examples, a cavitation peening nozzle may include a cylindrical tube and an organ tube cavitator at the distal end of the tube that delivers a cavitating jet of high-pressure fluid. The cavitator's inner passage may include an outlet portion that tapers from a proximal opening to a smaller distal opening.

[0007] The features, functions, and advantages may be achieved separately in various examples of the present disclosure or may be combined in yet other examples, further details of which can be understood with reference to the following description and drawings. [Brief explanation of the drawings]

[0008] [Figure 1]FIG. 1 is a block diagram of an exemplary cavitation peening system according to aspects of the present disclosure. [Figure 2] FIG. 1 is a schematic diagram of an exemplary portable cavitation peening system. [Figure 3] FIG. 1 is a cross-sectional view of an exemplary co-flow nozzle assembly according to aspects of the present disclosure. [Figure 4] FIG. 4 is an exploded cross-sectional view of the nozzle assembly of FIG. 3. [Figure 5] FIG. 4 is a detailed cross-sectional view of the tip of the nozzle assembly of FIG. 3 without the cavitation insert. [Figure 6] FIG. 4 is an axial view of the homogenizer plate of the nozzle assembly of FIG. 3. [Figure 7] FIG. 4 is an isometric view of a centering ring of the nozzle assembly of FIG. 3. [Figure 8] 4 is a schematic diagram of a first exemplary cavitation insert for the nozzle assembly of FIG. 3. [Figure 9] 4 is a schematic diagram of a second exemplary cavitation insert for the nozzle assembly of FIG. 3. [Figure 10] FIG. 4 is a schematic diagram of a third exemplary cavitation insert for the nozzle assembly of FIG. 3. [Figure 11] FIG. 4 is a schematic diagram of a fourth exemplary cavitation insert for the nozzle assembly of FIG. 3. [Figure 12] 4 is a detailed schematic diagram of a first exemplary outlet of the cavitation insert of FIG. 3; FIG. [Figure 13] 4 is a detailed schematic diagram of a second exemplary outlet of the cavitation insert of FIG. 3; FIG. [Figure 14] 4 is a detailed schematic diagram of a third exemplary outlet of the cavitation insert of FIG. 3; FIG. [Figure 15] 1 is a flowchart illustrating steps of an exemplary method of cavitation peening in accordance with the present teachings. DETAILED DESCRIPTION OF THE INVENTION

[0009] Various aspects and examples of cavitation nozzle assemblies with increased cavitation intensity, as well as related systems and methods, are described below and illustrated in the associated drawings. Unless otherwise specified, a nozzle assembly and / or its various components according to the present teachings may, but need not, include at least one of the structures, components, functionality, and / or variations described, illustrated, and / or incorporated herein in connection with the present teachings. Furthermore, unless specifically excluded, the process steps, structures, components, functionality, and / or variations described, illustrated, and / or incorporated herein in connection with the present teachings may be included in other similar devices and methods, including being interchangeable among the disclosed examples. The following description of various examples is merely exemplary in nature and is not intended to limit the present disclosure, its applications, or users. Additionally, the advantages provided by the examples described below are exemplary in nature, and not all examples provide the same advantages, or advantages to the same extent.

[0010] The detailed description includes the following sections, which immediately follow: (1) Overview; (2) Examples, Components, and Alternatives; (3) Exemplary Combinations and Alternatives; (4) Advantages, Features, and Benefits; and (5) Conclusion. The Examples, Components, and Alternatives sections are further divided into subsections A and B and are labeled accordingly.

[0011] overview In general, high-intensity cavitation nozzles may include an inner passage having a shape configured to change the flow dynamics of the discharged jet. For example, the inner passage may include a resonant chamber configured to enhance the fluctuations of the jet. As another example, the inner passage may have a conical outlet configured to increase the exit velocity of the jet. Dimensions of the inner passage shape, such as the resonant chamber length or cone angle, may be selected or adjusted to optimize the resulting increase in cavitation intensity. The inner passage shape may increase cavitation intensity without requiring an increase in flow rate.

[0012] The high-intensity cavitation nozzle may be part of a nozzle assembly used in a cavitation peening system. In some examples, the system may include a liquid environment, such as a water-filled tank, and the nozzle may be configured for use in a static water column, etc. In some examples, the system may be designed for use in an open air environment, handheld or otherwise, and the nozzle assembly may include an outer nozzle to direct an outer jet concentrically relative to the jet discharged by the cavitation nozzle. Such a nozzle assembly may be referred to as a co-flow nozzle or co-flow nozzle assembly.

[0013] 1 is a block diagram of an exemplary cavitation peening system 100, including an example of a high-intensity cavitation nozzle referred to as a cavitator 110. The cavitator may also be referred to as a cavitation nozzle and / or a cavitation insert. The cavitator 110 is part of a nozzle assembly 112. A fluid source 114 supplies fluid to the nozzle assembly through a conduit 116. A proximal end 118 of the conduit 116 is connected to the fluid source 114, and a distal end 120 of the conduit is connected to the nozzle assembly 112. The conduit 116 may include a high-pressure hose along with any other suitable fluid and / or electrical connections.

[0014] Fluid supply 114 delivers high-pressure fluid to nozzle assembly 112 through conduit 116. The fluid supply may include a high-pressure fluid pump and a supply of fluid, such as a water tank or connection to a water supply. The fluid supply may further include one or more additional pumps and / or various fluids depending on the process method selected. For example, the fluid supply may include a pump for low-pressure operation for use with a co-flow cavitation nozzle and / or may include a supply of abrasive slurry for an abrasive surface finish.

[0015] High-pressure fluid from the fluid source 114 may be ejected from the cavitator 110 of the nozzle assembly 112 toward the work surface and / or into the processing region as a cavitation jet. The cavitation jet may interact with the fluid environment to form cavitation bubbles. In some examples, the cavitation bubbles may excite abrasive particles suspended in the fluid environment. The workpiece may thereby be peened and surface-finished.

[0016] In some examples, the nozzle assembly 112 includes an outer nozzle 122. In such examples, the fluid supply 114 further delivers a low-pressure fluid to the nozzle assembly 112, which may be ejected by the outer nozzle 122 to create a fluid environment for forming cavitation bubbles. In some examples, the nozzle assembly 112 may be submerged in a fluid environment, such as a tank filled with water or an abrasive slurry.

[0017] Any desired fluid may be used for cavitation. Water is preferred as it is a safe, easy-to-handle, and inexpensive fluid. The properties of the fluid used, such as viscosity, may affect the collapse force of the cavitation bubbles, and the fluid may be selected to enhance the impact or to reduce the pressure required for the desired impact level. The fluid may also be selected according to the properties of the abrasive material used and / or to achieve the desired properties of the abrasive slurry.

[0018] The cavitator 110 may include either or both a tapered outlet 124 and a resonating chamber 126. In such examples, the cavitator may be referred to as a tapered cavitator or an organ pipe cavitator, respectively. Each strength feature can modify the flow dynamics of the cavitation jet emitted by the cavitator 110, thereby increasing the intensity of the cavitation generated by the nozzle assembly 112. The tapered outlet 124 may be formed by reducing the cross-sectional area of ​​a portion of the inner bore of the cavitator 110, which is immediately adjacent to the cavitator's outlet opening. The tapered outlet may be defined by an angled inner wall of the inner bore. The resonating chamber 126 may be formed within the cavitator between first and second reductions in the cross-sectional area of ​​the cylindrical inner bore. The resonating chamber may be referred to as the organ pipe shape of the cavitator 110.

[0019] Examples, Components, and Alternatives The following sections describe selected aspects of exemplary cavitation nozzle assemblies and related systems and / or methods. The examples in these sections are intended to be illustrative and should not be construed as limiting the overall scope of the disclosure. Each section may include one or more other examples and / or contextual or related information, functionality, and / or structure.

[0020] A. Exemplary Co-flow Nozzle Assembly 2-14, this section describes an exemplary co-flow cavitation nozzle assembly 200 that includes a modular, high-intensity cavitation nozzle insert 300, also referred to as a cavitation insert. As discussed above, the cavitation nozzle insert 300 is an example of a high-intensity cavitation nozzle, and the co-flow cavitation nozzle assembly 200 is an example of a nozzle assembly.

[0021] 2 is a schematic diagram of an exemplary portable water cavitation peening (PWCP) system, generally designated 210, including a nozzle assembly 200. The nozzle assembly is directed toward a treatment surface 214, which may be the surface of a workpiece and / or may be referred to as a processing site. Two flexible conduits 216, 218 supply pressurized water to the nozzle assembly, each connected to the nozzle assembly at its distal end. A tank 220 supplies water to two pumps: a first pump 222 connected to the proximal end of conduit 116 and a second pump 224 connected to the proximal end of conduit 218. The first pump 222 pressurizes the water to a first pressure, and the second pump 224 pressurizes the water to a second, lower pressure.

[0022] The nozzle assembly 200 discharges a first stream 226 of water at a first pressure and a second stream 228 of water at a second pressure. The two streams are discharged concentrically, resulting in the streams combining to generate cavitation bubbles. An operator may maintain the nozzle assembly 200 at a selected standoff distance from the treatment surface 214 based on factors including, but not limited to, the estimated cavitation intensity, the nozzle geometry, the material of the treatment surface 214, and / or the desired treatment. For example, the standoff distance may be approximately equal to twice the length of the generated cavitation bubbles.

[0023] The parallel flow configuration of nozzle assembly 200 may facilitate a wider range of applications for system 210. The portable system may be used in areas such as peening repair, final assembly processing, and / or large parts such as aircraft skin sections, without the size limitations or other constraints imposed by the need to submerge the parts being treated underwater.

[0024] Nozzle assembly 200 is designed to be manually operated and handheld. More specifically, the individual components and overall design of the nozzle assembly are configured for minimal size and weight, as further described below with reference to Figures 3-7. In this example, the nozzle assembly weighs 3 pounds (lb). Preferably, the nozzle assembly can weigh no more than about 5 lb to provide consistent control and minimize muscle fatigue to facilitate extended manual use.

[0025] The nozzle assembly further comprises an actuator 234 and a feedback mechanism 232. The actuator 234 is configured to be manually operated; for example, the actuator may comprise a mechanical trigger. The feedback mechanism 232 is configured to indicate the relative extent of surface modification at the processing site, in this example, the treatment surface 214, where the nozzle assembly is acting. For example, the feedback mechanism may comprise a display that displays a color map of calculated treatment durations for preselected treatment areas and / or displays readings from impact sensors located on the treatment surface. In some examples, the nozzle assembly may further comprise sensors, human-readable indicators, and / or controls for system parameters such as water temperature and pressure.

[0026] In some examples, the nozzle assembly 200 may be designed to integrate with an automated system and / or may be operated by a CNC robotic arm. In such examples, the nozzle assembly may include appropriate features such as a remote trigger, threads or other fastening features complementary to the robotic arm attachment, and / or an integrated programmable logic controller.

[0027] A sensor cluster 230 is placed in the water of the tank 220 to monitor relevant parameters of the water. For example, the cluster may include sensors for temperature, pressure, fluid level, viscosity, salinity, carbonate content, metal content, and / or oxygen content. In some examples, the system 210 may further include sensors in the conduits 216, 218 and / or nozzle assembly 200, such as one or more pressure and / or flow meters. Data from the sensor cluster 230 may be displayed by visual indicators on the exterior of the tank, and the data may be output to an electronic controller or communicated to an operator visually, audibly, or by other means.

[0028] In some examples, the system 210 may further include components or devices to optimize relevant characteristics of the flow delivered to the nozzle assembly 200. Examples include filters, valves, temperature controls, and pulsation reduction devices.

[0029] As described in more detail below, the first and second pressures, flow rates and velocity of system 210, and water temperature may be selected according to the desired cavitation intensity and the size and shape of nozzle assembly 200. In this example, system 210 is configured for water cavitation peening of machined, turned, cut, ground, polished, and / or additively manufactured metal components, for example, aluminum, corrosion-resistant steel (CRES), superalloy, and / or titanium aircraft components. The flow delivered from pump 222 to the nozzle assembly by conduit 216 is maintained at approximately 25 megapascals (MPa) and 150 meters per second (m / s). The flow delivered from pump 224 to the nozzle assembly by conduit 218 is maintained at approximately 0.1 MPa and 10 m / s. The water supplied by each pump is at approximately 30 degrees Celsius.

[0030] In general, any effective pressure, flow rate, and / or temperature may be used. Suitable values ​​may be different in instances where fluids other than water are used. Preferably, an operating temperature close to room temperature may be used to eliminate the need for significant heating or cooling. For many applications, a first pressure of approximately 5-35 MPa and any second pressure sufficient to produce a homogeneous flow will be effective. The flow rate may be limited by the pump capacity and nozzle size. Preferably, both the flow rate and nozzle size may be minimized so that an inexpensive, low-capacity pump can be used.

[0031] As shown in cross section in FIG. 3, nozzle assembly 200 includes an inner nozzle 236 and an outer nozzle 238, which define inner and outer flow passages 240 and 242, respectively. The dimensions of nozzle assembly 200 may be selected to minimize weight while maintaining a desired cavitation strength. In this example, the nozzle assembly has an overall length of approximately 45 centimeters (cm). Preferably, the nozzle assembly may be approximately 15-60 cm for handheld metal peening applications. Other sizes may be appropriate for other applications.

[0032] Similarly, nozzle materials may be selected to minimize weight while providing sufficient strength to withstand water pressure and not be damaged by cavitation. In this example, nozzle assembly components include aluminum alloys and stainless steel, as well as brass fittings and elastomeric O-ring seals. Any sufficiently lightweight and strong material may be used. Nozzles and / or nozzle components may be manufactured by any effective means, including, but not limited to, additive manufacturing, turning, casting, and machining.

[0033] Nozzle assembly 200 may be described as having a central axis 202 around which both inner nozzle 236 and outer nozzle 238 reside concentrically. Outer passage 242 and inner passage 240 are configured to deliver concentric, homogenous fluid flows suitable for generating cavitation bubbles. The flow generated by inner passage 240 may be referred to as a cavitation jet and is delivered at a higher pressure than the surrounding flow generated by outer passage 242. Fluid flows through the inner and outer passages in the direction indicated by arrow 241.

[0034] Inner nozzle 236 includes a high-pressure inlet 244, an inner tube 246, an inner tip 248, and a modular cavitation nozzle insert 250. The high-pressure inlet is connected to conduit 216 (FIG. 2) and a first end of inner tube 246. The second end of inner tube 246 is received by and threadably engages inner tip 248. Cavitation insert 250 is fully received by inner tip 248 and secured in place between the second end of the inner tube and the inner tip.

[0035] The outer nozzle 238 includes four low-pressure inlets 252, an inlet manifold 254, an outer tube 256, a tip connector 258, and an outer tip 260. The low-pressure inlets 252 are symmetrically arranged around the central axis 202 and may be said to be positioned at the vertices of a square. Two of the four inlets are shown in Figures 3 and 4. Each inlet 252 is connected to an inlet manifold 254 and threadedly secured to a first end of an outer tube 256. The tip connector 258 threadably engages the second end of the outer tube 256, and the outer tip is threadedly fastened to the tip connector to attach the outer tip 260 to the outer tube.

[0036] 4 is an exploded cross-sectional view of nozzle assembly 200, showing the components of inner nozzle 236 and outer nozzle 238 in further detail. As shown, inlet manifold 254 has a proximal portion 262 and a distal portion 264. The proximal portion includes recesses that receive high-pressure inlet 244 and low-pressure inlet 252, and the distal portion has a narrowed portion that receives outer tube 256 in a snug fit. Proximal portion 262 and distal portion 264 are threaded together to define a sealed manifold that collects water from low-pressure inlet 252 for communication with outer tube 256.

[0037] The inner tip 248 also has a proximal portion 266 and a distal portion 268. The proximal portion has a wedge-shaped configuration and abuts the flat proximal end of the distal portion to provide a smooth surface within the outer flow passage 242. Together, the two portions facilitate a strong bond and seal between the inner tip 248 and the inner tube 246 while minimizing impact on the outer flow passage.

[0038] The nozzle assembly 200 may be divided into parts and segments, as shown in Figure 4, or into more or fewer segments. The division shown in this example allows for inexpensive construction and facilitates disassembly of the modular cavitation insert for cleaning, part replacement, or exchange, as described in more detail below.

[0039] The outer nozzle 238 is concentric with the inner nozzle 236, and the inner nozzle extends through the outer nozzle. To accurately maintain concentricity, the nozzle assembly 200 includes a centering ring 270. In some instances, one or more additional centering rings may be used for stabilization purposes.

[0040] As shown in FIG. 3, the centering ring 270 is recessed in the inlet manifold 254 and contacts both the inlet manifold and the inner tube 246 to maintain relative positioning between the inner and outer nozzles. An isometric view of the centering ring 270 is shown in FIG. 7, showing a central opening 272 and two arcuate flow openings 274. The central opening is sized to receive the inner tube in a snug fit, and the outer circumferential surface 276 is configured to fit within the recess in the inlet manifold. The centering ring is circular to accommodate the cylindrical tubes of the inner and outer nozzles. The flow openings 274 are configured to allow maximum flow through the centering ring 270 without adversely affecting the strength of the ring.

[0041] 3 and 4, the nozzle assembly 200 further includes a perforated plate 280 to enhance flow uniformity through the outer flow passage 242. The perforated plate is positioned immediately downstream of the centering ring 270 and is similarly received in a recess in the inlet manifold 254. The plate may thus be positioned to eliminate turbulence and inhomogeneities caused by mixing within the manifold and deliver a smooth flow downstream to the outer pipe 256. FIG. 6 is an axial view of the perforated plate 280, showing a central opening 282 and a plurality of smaller, circular flow openings 284. The central opening is sized to receive the inner pipe with a snug fit, and the outer peripheral edge 286 is configured to fit within the recess in the inlet manifold. The flow openings 284 are radially symmetrically positioned for symmetrical flow.

[0042] 5, outer tip 260 tapers toward a distal exit opening 285. An inner wall 287 of the outer tip is angled inward in two steps, with the first step angled at approximately 30 degrees relative to central axis 202 and the second step angled at approximately 15 degrees relative to the central axis 202. That is, the distal-most or outer portion of inner wall 287 forms an oblique angle 289 of approximately 15 degrees with respect to central axis 202. Preferably, angle 289 may be between approximately 5 and 45 degrees.

[0043] The outer tip 260 tapers, reducing the cross-sectional area of ​​the outer flow passage 242. The cross-section of the outer flow passage at the outer tip is annular, defined between the inner wall 287 and the inner tip 248. The cross-sectional area of ​​the outer flow passage is proportional to the difference between the square of the inner diameter 288 of the outer tip 260 and the square of the outer diameter of the inner tip 248.

[0044] In this example, the inner diameter 288 of the outer tip 260 at the exit opening 285 is about 25 millimeters (mm), the outer diameter of the inner tip 248 is about 12 mm, and the cross-sectional area of ​​the outer flow passage 242 is about 380 mm 2 Generally, the dimensions of the outer tip 260 may be proportional to the overall nozzle size. A larger exit area and higher flow rate may increase cavitation intensity. However, a higher flow rate may require the use of larger amounts of water and pumping with larger capacity pumps, increasing equipment and processing costs. Therefore, it may be preferable to achieve the desired cavitation intensity with a nozzle geometry and limited flow. Therefore, it may be preferable to have the inner diameter 288 be less than about 50 mm.

[0045] Referring again to FIG. 3 , during operation of the nozzle assembly 200, high-pressure water flows from the high-pressure inlet 244 through the inner passage 240, through the inner tube 246, and out the cavitation insert 250. The inner passage is primarily defined by the cylindrical inner tube 246, which has a generally circular cross-sectional shape. The high-pressure flow is converted into a cavitating jet by the cavitation insert 250. Low-pressure water flows from the low-pressure inlet 252 through the inlet manifold 254, the centering ring 270, the perforated plate 280, and the outer tube 256 into the outer passage 242, before exiting at the outer tip 260. The outer passage 242 is defined between the outer tube 256 and the inner tube 246, and then between the outer tip 260 and the inner tip 248, and has a generally annular shape.

[0046] In this example, the nozzle assembly 200 further includes a plurality of high-strength cavitation nozzle inserts 300, as shown in Figures 8 through 14 and described in more detail below. In Figures 3 and 4, the illustrated cavitation inserts 250 have a cavitation nozzle shape known in the art, specifically, a cylindrical bore with a single constriction toward a cylindrical outlet. The cavitation inserts 250 may also be described as unexcited or unreinforced inserts. Each nozzle insert 300 has a shape that enhances cavitation strength and may preferably be used with the unexcited cavitation inserts 250.

[0047] In general, nozzle assembly 200 may be used with a single cavitation insert design, multiple cavitation insert designs, and / or may include multiple interchangeable cavitation inserts. Using inserts rather than a single inner nozzle may reduce the cost of replacing parts damaged by long-term exposure to cavitation and may facilitate changing the nozzle geometry as desired to tailor nozzle assembly 200 for a particular peening application.

[0048] Each insert 250, 300 has a matching outer shape that is complementary to the inner tip 248. More specifically, each insert includes a cylindrical outer wall 302 with a shoulder 304 at its proximal end, as shown in Figures 8-11. An inner passageway 306 extends from a planar proximal face having a circular inlet opening 308 to a planar distal face having a smaller circular outlet opening 310. The shape of the inner passageway 306 between the inlet and outlet openings, and the size of the outlet opening 310, vary among the inserts, while the size of the inlet opening 308 in each insert is the same.

[0049] As shown in the example of unexcited insert 250 in Figure 3, each insert is sized to be snugly received and sealed within the distal portion 268 of inner tip 248. A shoulder 304 of the insert is sandwiched between inner tube 246 and an inward protrusion of the inner tip. The inner tube abuts a proximal face of the insert to secure the insert to the nozzle assembly 200. Inner tube 246 may be unscrewed from inner tip 248 to allow the insert to be replaced or exchanged.

[0050] 8-14 show examples of cavitation inserts 300 having inner passageway 306 geometries configured to enhance cavitation intensity. Corresponding reference numerals are used to indicate elements shared by two or more insert designs. It should also be noted that the inner passageway 306 geometries described and illustrated may be used in other nozzle designs, such as co-flow nozzles with a single inner nozzle, or single-flow cavitation nozzles in a stationary water column, to similarly enhance cavitation intensity.

[0051] FIG. 8 shows a first example of a high-intensity cavitation nozzle insert 300, in which the resonator insert 400 has an organ pipe shape. The resonator insert's inner passageway 306 has three sections: an inlet section 412, a middle section 414, and an outlet section 416. The middle section may also be referred to as the organ pipe section. Each section is cylindrical, and all sections are coaxial. The inlet section 412 has a diameter 418, the organ pipe section 414 has a diameter 420, and the outlet section 416 has a diameter 422. The diameter 422 of the outlet section 416 is also the diameter of the outlet opening 310. The diameter 418 is larger than the diameter 420, which is larger than the diameter 422. In other words, the inner passageways have successively smaller diameters.

[0052] The resonator insert 400 may be described as having two constrictions or reductions in cross-sectional area, resulting in a change in diameter and forming an organ tube shape. That is, an organ tube portion 414 may be defined between the two constrictions. Pressure oscillations occurring at the nozzle exit may be reinforced by reflection from the upstream reduction. Such reinforcement may be referred to as passive excitation and / or autoresonance.

[0053] Diameters 418, 420, and 422 may be selected such that there are two successive large reductions in the cross-sectional area of ​​the inner passage of resonance insert 400 as water passes through the inner nozzle. In other words, the diameters may be selected to be sufficiently different to create an organ pipe effect within resonance insert 400. In this example, diameter 418 is more than twice as large as diameter 420, and diameter 420 is more than four times as large as diameter 422. In some examples, other relative diameters may be selected to optimize the organ pipe effect and / or cavitation intensity.

[0054] The organ pipe section 414 may be referred to as a resonant chamber and / or a reverberant chamber. The organ pipe section has a length 424, which may be selected according to a desired resonant mode and / or other resonant characteristics. More particularly, the length 424 may be selected according to a desired standing wave wavelength. In this example, the resonant insert 400 is configured for a first resonant mode, with a standing wave four times the length 424.

[0055] The resonating insert 400 may be described in terms of the Strouhal number. The length 424 of the organ tube section 414 may determine the pulsation frequency of the resonating insert. The Strouhal number may then be determined by the pulsation frequency, the diameter 422 of the outlet section 416, and the velocity of the cavitation plume. For a selected geometry, there may be a critical frequency at which cavitation intensity is maximized because large-scale turbulent motion organizes into cavitation vortex rings. In this example, the Strouhal number of the resonating insert 400 is 0.28. In some examples, the Strouhal number of the resonating insert may be approximately 0.2 to 0.6.

[0056] In this example, diameter 418 is approximately 10 mm, diameter 420 is approximately 4 mm, and diameter 422 is approximately 1 mm. With these dimensions and configurations of nozzle assembly 200, as described above, length 424 may be approximately 5-15 mm. As shown in Figure 8, length 424 is approximately 7.5 mm and the pulsation frequency of organ tube section 414 is approximately 50 kilohertz.

[0057] In comparative testing of the single constriction geometry of the unexcited cavitation insert 250 with the resonant insert 400 of this example, multiple passes over an aluminum alloy sheet at optimal standoff distances showed that the resonant insert exhibited approximately a 60 percent (%) increase in both mass loss and sheet curvature, resulting in deeper compressive residual stresses within the material. Analysis of impact pressure measurements indicated increased strength due to the high frequency of the powerful cavitation event.

[0058] FIG. 9 shows a second example of a high-intensity cavitation nozzle insert 300, a two-chamber resonator insert 500 also having an organ pipe shape. The inner passageway 306 of the two-chamber resonator insert has four sections: an inlet section 512, a first organ pipe section 514, a second organ pipe section 515, and an outlet section 516. Each section is cylindrical, and all sections are coaxial. The inlet section 512 has a diameter 518, the first organ pipe section 514 has a diameter 520, the second organ pipe section 515 has a diameter 521, and the outlet section 516 has a diameter 522. Diameter 518 is larger than diameter 520, which is larger than diameter 521, which is larger than diameter 522.

[0059] The resonator insert 500 may be described as having three constrictions or reductions in cross-sectional area, resulting in a change in diameter and forming an organ tube shape. That is, each organ tube section 514, 515 may be defined between two constrictions. Pressure oscillations occurring at the nozzle outlet may be intensified by reflection from the upstream reductions, similar to the resonator insert 400.

[0060] Diameters 520, 521 may be selected such that each constriction constitutes a large reduction in the cross-sectional area of ​​the inner passage of resonator insert 500, such that each organ tube section 514, 515 acts as a resonator chamber. First organ tube section 514 has a length 524, and second organ tube section 515 has a length 525. Each length may be selected depending on the desired standing wave wavelength, resonant mode, and / or Strouhal number.

[0061] The inclusion of additional organ tube sections can increase cavitation intensity, with associated diameters and lengths selected to achieve effective resonance. In general, a resonating insert may include any number of organ tube sections and / or resonating chambers. Additional organ tube sections may require a larger ratio of inlet opening 308 to outlet opening 310 so that the cross-sectional area reduction between sections is sufficiently large, which may require a correspondingly larger insert and / or inner nozzle. A preferred resonating insert may therefore include the maximum number of organ tube sections that will produce effective resonance achievable with the selected manufacturing method and cavitation insert dimensions.

[0062] FIG. 10 illustrates a third example of a high-strength cavitation nozzle insert 300, which includes a convergent insert 600 with a decreasing outlet diameter. The convergent insert's inner passage 306 has two sections: an inlet section 612 and an outlet section 616. The two sections are coaxial. The inlet section 612 is cylindrical with a constant diameter 618, and the outlet section 616 tapers from a first diameter, or inlet diameter 622, to a second diameter, or outlet diameter 623. The outlet diameter 623 is also the diameter of the outlet opening 310.

[0063] Tapered insert 600 may be described as having two narrowings or reductions in cross-sectional area, with the change in diameter occurring from inlet portion 612 to outlet portion 616, and at outlet portion 616, the inner passage narrows from inlet diameter 622 to outlet diameter 623.

[0064] The tapered shape of the outlet section 616 can increase the velocity of the cavitation jet generated by the tapered insert 600, thereby increasing the velocity difference between the inner and outer flows generated by the co-flow nozzle assembly. This increased velocity difference intensifies the cavitation effect of the coaxial flows, resulting in more high intensity cavitation events.

[0065] Unlike the increased cavitation seen in divergent fuel injection nozzles, the shape of the convergent insert 600 is not generated by a pressure drop inside the insert caused by flow separation. Instead, increased cavitation inception can occur at or outside the exit orifice 310 due to shear between the flows. This distribution may be advantageous for cavitation peening because it avoids damage to the convergent insert 600 and enhances the cavitation effect on the machined surface. A similar effect may be achieved with the convergent exit shape of a submerged single-flow nozzle by increasing the shear between the generated cavitation jet and the surrounding stationary liquid.

[0066] As shown in FIG. 10 , the outlet portion 616 of the tapered insert 600 is conical in shape. The outlet portion may be described as frusto-conical. The outlet portion 616 is shown in more detail in FIG. 12 and includes a linearly sloped inner wall 626. The inner wall slopes continuously from the inlet portion 612 to the outlet 310 and forms an angle 628 with respect to the central axis 301 of the insert. When the tapered insert 600 is installed in the nozzle assembly 200 as shown in FIG. 3 , the central axis 301 coincides with the central axis 202 of the nozzle assembly, and the inner wall 626 forms an angle 628 with respect to the central axis 202.

[0067] Referring again to FIG. 12 , in the illustrated example, angle 628 is approximately 8 degrees. Inlet diameter 622 is approximately 910 micrometers (μm), and outlet diameter 623 is approximately 845 μm. Exit section 616 is circular in cross section, perpendicular to central axis 301, along the entire length of the section. The exit has a cross-sectional area reduction of approximately 15%. Generally, a larger reduction in cross-sectional area can increase cavitation intensity, but may also result in increased energy loss. Therefore, it is desirable to balance increased intensity with maintaining force. A cross-sectional area reduction of approximately 13-20% may be preferred. For a frusto-conical exit, such as exit section 616, such a reduction may be achieved by angle 628 of approximately 1-15 degrees. Above 45 degrees, energy loss may outweigh the cavitation intensity benefit.

[0068] In a comparative test of the unexcited cavitation insert 250 (FIGS. 3 and 4) with a zero cone angle outlet design and the tapered insert with outlet 616 shown in FIG. 12, the resonant insert exhibited approximately a 20% increase in mass loss and a 65% increase in sheet curvature during multiple passes over an aluminum alloy sheet at optimal standoff distance. The frequency of high intensity cavitation events recorded an approximately 30% increase.

[0069] The reduction in cross-sectional area of ​​the outlet portion of the convergent insert 600 may be achieved by other shapes. Figures 13 and 14 show two examples of such shapes, each with a nonlinearly tapered inner wall. In the example shown in Figure 13, the convergent insert 600 has a curved outlet portion 630. The curved outlet portion has a generally parabolic inner wall 632, similar in shape to the convergent portion of a Laval nozzle or a converging-diverging nozzle. The curved outlet portion 630 has a larger inlet diameter 622 and a larger cross-sectional reduction than the conical outlet portion 616 (Figure 12). Such a reduction, combined with a curve, can significantly accelerate the water flow, but may be more difficult and expensive to manufacture to the micrometer scale required in this example handheld co-flow nozzle assembly.

[0070] In the example shown in FIG. 14 , the convergent nozzle 600 has a stepped outlet section 634. The stepped outlet section includes three sections: a first cylindrical section, a second conical section, and a third cylindrical section. The inner wall 636 of the conical section forms an angle 638 with the central axis 301. Although angle 638 is larger than angle 628 of the conical outlet section 616 ( FIG. 12 ), the stepped outlet 634 has the same inlet diameter 622 and reduction in cross-sectional area as the conical section. A stepped shape, such as the outlet section 634, may be useful for achieving finer or more complex changes in water flow. Any effective combination of straight and / or curved sections may be used to achieve the desired flow dynamics. The transitions between the sections may be stepped, sloped, or smoothly shaped.

[0071] FIG. 11 shows a fourth example of a high-intensity cavitation nozzle insert 300, in which the coupling insert 700 has an organ tube shape and an outlet with a decreasing diameter. The coupling insert's inner passage 306 has three sections: an inlet section 712, an organ tube section 714, and an outlet section 716. The inlet and organ tube sections are each cylindrical, and all sections are coaxial. The inlet section 712 has a diameter 718, the organ tube section 714 has a diameter 720, and the outlet section 716 tapers from an inlet diameter 722 to an outlet diameter 723. The organ tube section 714 further has a length 724, which may be selected depending on the wavelength of the desired standing wave.

[0072] Diameter 718 is larger than diameter 720, which is larger than diameter 722, which is larger than diameter 723. Interlocking insert 700 may be described as having three constrictions or reductions in cross-sectional area, with the changes in diameter occurring from inlet portion 712 to organ tube portion 714, from the organ tube portion to outlet portion 716, and at the outlet portion where the inner passage narrows from inlet diameter 722 to outlet diameter 723.

[0073] The coupling insert 700 can produce a cavitation intensity enhancement effect on the water flow of both the resonating insert 400 (FIG. 8) and the tapered insert 600 (FIG. 10). Pressure oscillations occurring at the nozzle outlet are strengthened by reflection from the upstream contraction, and the tapered shape of the outlet section can increase the velocity of the generated cavitation jet. In some examples, the coupling insert 700 can have an additional resonating chamber, as shown in FIG. 9, and / or a non-linear outlet shape, as shown in FIGS. 13 and 14.

[0074] B. Exemplary Methods This section describes the steps of an exemplary method 800 of cavitation peening, see FIG. 15. Aspects of the cavitation nozzle described above may be used in the method steps described below. Where appropriate, references are made to components and systems that may be used to perform each step. These references are for illustrative purposes and are not intended to limit the manner in which any particular step of the method may be performed.

[0075] Figure 15 is a flowchart illustrating steps performed in an exemplary method, and is not intended to describe the complete or entire process of the method. Although various steps of method 800 are described below and illustrated in Figure 15, the steps need not all be performed, and in some cases may be performed simultaneously or in a different order than that illustrated.

[0076] In step 810, the method includes supplying high-pressure fluid to a nozzle. The nozzle may be a co-flow cavitation peening nozzle or a single-flow cavitation peening nozzle submerged in a tank or other stationary column of fluid. The high-pressure fluid, such as water, may be supplied to the nozzle by a pump at a selected pressure, flow rate, and / or temperature. The nozzle may be positioned by an automated system and / or by an operator at a selected standoff distance from the surface of the workpiece being treated. The workpiece may include any part, multiple parts, and / or material requiring peening of one or more surfaces.

[0077] Step 812 of method 800 includes directing a flow of high-pressure fluid through a distal structure of a nozzle having a cavitation-enhancing geometry. The nozzle may include an internal passageway or bore extending from a proximal or upstream end of the nozzle to a distal-most or downstream end of the nozzle. The internal passageway may direct the supplied high-pressure fluid through the nozzle.

[0078] The nozzle distal structure may be located at the downstream end of the nozzle, and the cavitation-enhancing shape may comprise a constriction or reduction in the cross-sectional area of ​​the inner passage. The distal structure may comprise an integral part of a unitary nozzle, may comprise a separate nozzle tip, and / or may comprise a modular, replaceable insert. The structure may be referred to as a cavitator, a cavitation nozzle, and / or a cavitation insert.

[0079] Optional substep 814 of step 812 includes reinforcing the high-pressure fluid flow fluctuations in a resonating chamber. The resonating chamber, which may be referred to as an organ tube chamber and / or organ tube shape, may be defined between two constrictions in the inner passage at the distal structure of the nozzle. In other words, the distal structure may have two successive large reductions in the cross-sectional area of ​​the inner passage of the nozzle. The inner diameters of the structures may be selected to be sufficiently different to produce an organ tube effect. The length of the resonating chamber may be selected depending on the desired resonant mode and / or other resonant characteristics. More specifically, the length may be selected depending on the wavelength of the desired standing wave. Pressure oscillations occurring at the nozzle outlet may be reinforced by reflection from the upstream constriction.

[0080] Optional substep 816 of step 812 includes increasing the flow velocity at a convergent outlet. The convergent outlet may comprise a distal-most portion of the nozzle's inner passage defined within the distal structure. The convergent outlet may narrow from a first diameter at the upstream end of the outlet to a second diameter at the downstream end of the outlet. In some examples, the outlet may decrease in diameter from the first diameter to the second diameter linearly, e.g., frustoconically. In some examples, the outlet may decrease monotonically but non-linearly, e.g., parabolically, from the first diameter to the second diameter. The convergent outlet may increase the velocity of fluid flow through the inner passage from the upstream end of the outlet to the downstream end of the outlet.

[0081] Step 818 includes ejecting a cavitation jet from the nozzle. The cavitation jet may interact with a fluid environment, such as a surrounding coaxial flow of low-pressure fluid or a static fluid column, to form a vortex of cavitation bubbles. The collapse of the cavitation bubbles may peen the workpiece. Method steps 810-818 may be repeated throughout the peening process, either as an automated system and / or by an operator scanning the nozzle across the workpiece surface.

[0082] Illustrative Combinations and Alternative Examples This section describes additional aspects and features of high-intensity cavitation nozzles and related systems and methods, presented without limitation in a series of paragraphs, some or all of which may be presented in alphanumeric order for clarity and efficiency. Each of these paragraphs may be combined in any appropriate manner with one or more other paragraphs and / or with disclosure elsewhere in this application, including material incorporated by reference via cross-reference. Some paragraphs below explicitly refer to and further qualify other paragraphs, providing, without limitation, examples of some suitable combinations.

[0083] A0. A fluid supply source; a conduit having a proximal end and a distal end, the proximal end being connected to a fluid source; a portable nozzle assembly connected to a distal end of the conduit, the nozzle assembly comprising: an inner nozzle having a cavitation insert and directing a first flow of high-pressure fluid; an outer nozzle for directing a second stream of low pressure fluid concentrically around the first stream; Equipped with The cavitation insert has an inner passage having at least two reductions in cross-sectional area; Equipment for cavitation peening.

[0084] A1. The apparatus of A0, further comprising a plurality of interchangeable cavitation inserts, wherein the nozzle assembly is configured to allow the cavitation insert of the inner nozzle to be replaced with another cavitation insert of the plurality of interchangeable cavitation inserts.

[0085] A2. The apparatus of A0 or A1, wherein the cavitation insert has an organ tube shape.

[0086] A3. The device described in A2, wherein the inner passage of the cavitation insert is cylindrical and has a proximal portion, an intermediate portion, and a distal portion, the proximal portion having a first inner diameter, the intermediate portion having a second inner diameter, and the distal portion having a third inner diameter, the first inner diameter being larger than the second inner diameter, and the second inner diameter being larger than the third inner diameter.

[0087] A4. A device described in any one of A0 to A3, wherein the inner passage of the cavitation insert has a proximal portion and a distal portion, the distal portion tapering from a first diameter to a second, smaller diameter.

[0088] A5. The apparatus of A4, wherein the distal portion of the inner passage is defined by an inner wall that forms an angle of approximately 1 to 15 degrees relative to the central axis of the nozzle assembly.

[0089] A6. The apparatus of any one of A0 to A5, wherein the portable nozzle assembly weighs less than 5 lbs.

[0090] A7. The apparatus of any one of A0 to A6, wherein the second stream is delivered from the outer nozzle through an opening less than about 50 mm in diameter.

[0091] A8. The apparatus of any one of A0 to A7, wherein the second stream is delivered from a tapered tip of the outer nozzle.

[0092] A9. The device of A8, wherein the tapered tip has an inner wall that forms an angle of about 15 to 30 degrees with respect to the central axis of the nozzle assembly.

[0093] A10. An apparatus as described in any one of A0 to A9, further comprising a feedback mechanism that indicates the relative extent of surface modification at the processing site being acted upon by the nozzle assembly.

[0094] A11. An apparatus according to any one of A0 to A10, wherein the nozzle assembly comprises an actuator for manual operation.

[0095] A12. An apparatus described in any one of A0 to A11, wherein the nozzle assembly has a ring structure disposed on the outer nozzle, surrounding the inner nozzle and maintaining the inner nozzle in a coaxial arrangement relative to the outer nozzle while allowing fluid to flow through the outer nozzle.

[0096] A13. An apparatus described in any one of A0 to A12, wherein the nozzle assembly includes an annular plate having a plurality of circular holes, the annular plate being disposed in the outer nozzle and surrounding the inner nozzle to homogenize the flow of fluid through the outer nozzle.

[0097] B0. Cylindrical tube and an organ tube cavitator at the distal end of the cylindrical tube, the organ tube cavitator delivering a cavitating jet of high-pressure fluid; Equipped with the cavitator inner passage has a proximal portion, an intermediate portion, and a distal portion, the proximal portion having a first inner diameter, the intermediate portion having a second inner diameter, and the distal portion having a third inner diameter, the first inner diameter being larger than the second inner diameter, and the second inner diameter being larger than the third inner diameter; Cavitation peening nozzle.

[0098] B1. The nozzle of B0, wherein the first inner diameter is at least twice as large as the second inner diameter.

[0099] B2. The nozzle of B0 or ​​B1, wherein the second inner diameter is at least four times the size of the third inner diameter.

[0100] B3. The nozzle according to any one of B0 to B2, wherein the length of the intermediate portion is about 5 to 15 mm.

[0101] B4. The nozzle according to any one of B0 to B3, wherein the length of the intermediate portion is approximately 5 to 10 mm.

[0102] B5. The nozzle of any one of B0 to B4, wherein the inner diameter of the third portion is less than about 1 mm.

[0103] B6. The nozzle of any one of B0 to B5, wherein the organ pipe cavitator is configured to generate a cavitating jet having a Strouhal number between 0.2 and 0.6.

[0104] B7. The nozzle of any one of B0 to B6, wherein the organ pipe cavitator is configured to generate a cavitating jet having a Strouhal number of about 0.28.

[0105] B8. A nozzle as described in any one of B0 to B7, further comprising a nozzle assembly delivering a first flow of fluid through a cavitation peening nozzle and a second flow of fluid concentrically flowing around the first flow through an outer nozzle, the first flow being delivered at a higher pressure than the second flow.

[0106] C0. Cylindrical tube and a tapered cavitator at a distal end of the cylindrical tube, the tapered cavitator delivering a cavitating jet of high pressure fluid; Equipped with the inner passage of the cavitator has an outlet portion that tapers from a proximal opening to a smaller distal opening; Cavitation peening nozzle.

[0107] C1. The nozzle described in C0, wherein the cross-sectional area of ​​the distal opening is approximately 10-30% smaller than the cross-sectional area of ​​the proximal opening.

[0108] C2. A nozzle as described in C0 or C1, wherein the outlet portion is defined by an inner wall of the tapered cavitator, the inner wall forming an angle of at least about 8 degrees with respect to the central axis of the nozzle assembly.

[0109] C3. The nozzle of any one of C0 to C2, wherein the outlet portion is frustoconical.

[0110] C4. A nozzle according to any one of C0 to C3, wherein the outlet portion is defined by an inner wall of a tapered cavitator, the inner wall tapering non-linearly from the proximal opening to the distal opening.

[0111] C5. The nozzle of any one of C0 to C4, further comprising a nozzle assembly that delivers a first flow of fluid through a cavitation peening nozzle and a second flow of fluid concentrically flowing around the first flow through an outer nozzle, the first flow being delivered at a higher pressure than the second flow.

[0112] D0. A fluid supply source; a conduit having a proximal end and a distal end, the proximal end being connected to a fluid source; a portable nozzle assembly connected to a distal end of the conduit, the nozzle assembly including a cavitation nozzle having an organ tube shape; An apparatus for cavitation peening comprising:

[0113] D1. The apparatus of D0, wherein the cavitation nozzle includes an inner passage having a proximal portion, an intermediate portion, and a distal portion, the proximal portion having a first inner diameter, the intermediate portion having a second inner diameter, and the distal portion having a third inner diameter, the first inner diameter being larger than the second inner diameter, and the second inner diameter being larger than the third inner diameter.

[0114] D2. The apparatus of D0 or D1, wherein the nozzle assembly is configured to deliver a first flow of fluid through the cavitation nozzle and a second flow of fluid flowing concentrically around the first flow, the first flow being delivered at a higher pressure than the second flow.

[0115] D3. The apparatus of D2, wherein the second stream is delivered from the nozzle assembly through an opening having a diameter of at least about 20 mm.

[0116] D4. The apparatus of D2 or D3, wherein the second stream is delivered from the nozzle assembly through a funnel-shaped tip of the nozzle assembly.

[0117] D5. The apparatus of D4, wherein the funnel-shaped tip has an outer wall that forms an angle of about 30 degrees with respect to a central axis in the direction of flow of the first fluid stream.

[0118] E0. An outer tube that guides the flow of a first fluid under a first fluid pressure; an inner tube coaxial with the outer tube and configured to guide a flow of a second fluid at a second fluid pressure, the second fluid pressure being higher than the first fluid pressure; The organ pipe nozzle at the outlet of the inner pipe and Equipped with The first fluid stream and the second fluid stream are combined to generate cavitation bubbles; Cavitation peening nozzle assembly.

[0119] F0. An outer tube that guides the flow of low-pressure fluid; An inner tube, an inlet for receiving a flow of high pressure fluid; a first narrowing in the diameter of the inner passage of the inner tube; a second narrowing of the diameter of the inner passage; an outlet for delivering the cavitating jet; Equipped with a first constriction in diameter and a second constriction in diameter form a resonant chamber adjacent the outlet of the inner tube; Cavitation peening parallel flow nozzle assembly.

[0120] G0. A high pressure fluid supply source; a parallel flow nozzle assembly having a resonating chamber for enhancing the oscillation of a jet of high pressure fluid; Equipped with The resonant chamber is defined between a first reduction in cross-sectional area of ​​the inner tube of the parallel flow nozzle assembly and a second reduction in cross-sectional area of ​​the inner tube; Portable cavitation peening system.

[0121] H0. A step of discharging a cavitation jet coaxially with and surrounded by a low-pressure jet; forming cavitation bubbles on the machining surface; Including, A method of cavitation peening, wherein the step of ejecting a cavitation jet includes the step of directing a high pressure stream of fluid through an organ tube nozzle to enhance fluctuations in the fluid stream.

[0122] Advantages, Features, and Benefits The various examples of nozzle assemblies described herein offer several advantages over known solutions for cavitation peening. For example, the illustrative examples described herein demonstrate increased cavitation intensity and increased frequency of powerful cavitation events.

[0123] Additionally, and among other advantages, the illustrative examples described herein require smaller pumps and lower water flows.

[0124] Additionally, and among other advantages, the exemplary examples described herein are smaller and lighter than existing co-flow nozzles.

[0125] Additionally, and among other advantages, the exemplary embodiments described herein have less wear and a longer life than non-excited nozzle designs.

[0126] Additionally, and among other advantages, the illustrative examples described herein are suitable for extended handheld use.

[0127] Additionally, and among other advantages, the illustrative examples described herein are modular so that they can be tailored to specific peening applications.

[0128] No known system or device can perform this function, particularly one that can achieve high cavitation intensity from a confined water flow. Accordingly, the illustrative examples described herein are particularly useful for portable cavitation peening systems. However, not all examples described herein provide the same or the same degree of benefit.

[0129] conclusion The present disclosure described above may encompass multiple different examples having independent utility. While each is disclosed in its preferred form(s), the specific examples disclosed and illustrated herein are susceptible to numerous variations and therefore should not be considered limiting. Where headings are used within this disclosure, such headings are for organizational purposes only. The subject matter of the present disclosure includes all new and unobvious combinations and subcombinations of the various elements, forms, functions, and / or properties disclosed herein. The following claims particularly point out certain combinations and subcombinations that are deemed new and unobvious. Other combinations and subcombinations of forms, functions, elements, and / or properties may be claimed in applications claiming priority from this or a related application. Such claims, whether broader, narrower, equivalent, or different in scope from the original claims, are still considered to be within the subject matter of the present disclosure. [Explanation of symbols]

[0130] 100 Cavitation Peening System 110 Cavitation 112 nozzle assembly 114 Fluid supply source 116 Conduit 118 Proximal end 120 distal end 122 outer nozzle 124 Tapered outlet 126 Resonance chamber 200 Nozzle Assembly 202 Center axis 210 System 214 Treatment Surface 216 Conduit 218 Conduit 220 Tank 222 First Pump 224 Second Pump 226 First Stream 228 Second Stream 230 Sensor Cluster 232 Feedback Mechanism 234 Actuator 236 Inner nozzle 238 Outer Nozzle 240 Inner flow path 241 Fluid flow direction 242 Outer channel 244 High Pressure Inlet 246 Inner tube 248 Inner tip 250 Cavitation Insert 252 Low pressure inlet 254 Inlet manifold 256 Outer tube 258 Tip Connector 260 Outer tip 262 Proximal part 264 Distal portion 266 Proximal part 268 Distal part 270 Centering ring 272 Central opening 274 Flow Opening 276 Outer surface 280 Perforated plate 282 Central Opening 284 Flow Opening 285 distal exit opening 286 Outer edge 287 Interior wall 288 Inner diameter of outer tip 289 Bevel 300 Cavitation Nozzle Insert 301 Center axis 302 Exterior wall 304 Shoulder 306 Inner passage 308 Inlet opening 310 Exit opening 400 Resonance Insert 412 Entrance section 414 Organ Pipe Section 416 Exit section 418 Inlet diameter 420 Diameter of organ pipe 422 Outlet diameter 424 Length of organ pipes 500 Resonance Insert 512 Entrance section 514 First organ pipe section 515 Second organ pipe section 516 Exit part 518 Inlet diameter 520 Diameter of first organ pipe section 521 Diameter of second organ pipe 522 Outlet diameter 524 Length of the first organ pipe section 525 Length of second organ pipe section 600 Tapered Insert 612 Entrance section 616 Exit part 618 Inlet diameter 622 inlet diameter 623 Outlet diameter 626 Interior wall 628 angle 630 Exit part 632 Interior wall 634 Exit part 636 Interior wall 638 angle 700 Coupled Insert 712 Entrance section 714 Organ pipe section 716 Exit part 718 Inlet diameter 720 Diameter of organ pipe 722 inlet diameter 723 outlet diameter 724 Length of organ pipes 800 ways

Claims

1. a fluid supply; a conduit having a proximal end and a distal end, the proximal end being connected to the fluid source; a portable nozzle assembly connected to the distal end of the conduit, the nozzle assembly comprising: an inner nozzle having a cavitation insert and directing a first flow of high pressure fluid; an outer nozzle for directing a second stream of low pressure fluid concentrically around the first stream; a portable nozzle assembly having Equipped with the cavitation insert has an inner passageway including at least two reductions in cross-sectional area; the inner passage of the cavitation insert having a proximal portion and a distal portion, the distal portion tapering from a first diameter to a second, smaller diameter; Equipment for cavitation peening.

2. 10. The apparatus of claim 1, further comprising a plurality of interchangeable cavitation inserts, the nozzle assembly configured to allow the cavitation insert of the inner nozzle to be replaced with another cavitation insert of the plurality of interchangeable cavitation inserts.

3. 3. The apparatus of claim 1 or 2, wherein the cavitation insert has an organ tube shape.

4. 4. The device of claim 3, wherein the inner passage of the cavitation insert is cylindrical and has a proximal portion, an intermediate portion, and a distal portion, the proximal portion having a first inner diameter, the intermediate portion having a second inner diameter, and the distal portion having a third inner diameter, the first inner diameter being larger than the second inner diameter, and the second inner diameter being larger than the third inner diameter.

5. The apparatus of any one of claims 1 to 4, wherein the distal portion of the inner passage is defined by an inner wall that forms an angle of between 1 and 15 degrees with respect to a central axis of the nozzle assembly.

6. 6. The apparatus of claim 1, wherein the portable nozzle assembly weighs less than 2.27 kg.

7. 7. The apparatus of claim 1, wherein the second stream is delivered from the outer nozzle through an opening having a diameter of less than 50 mm.

8. An apparatus described in any one of claims 1 to 7, wherein the second flow is ejected from a tapered tip of the outer nozzle.

9. the nozzle assembly A cylindrical tube; an organ pipe cavitator at a distal end of the cylindrical pipe, the organ pipe cavitator delivering a cavitating jet of high-pressure fluid; The apparatus of claim 1 , further comprising:

10. 10. The apparatus of claim 9, wherein the first inner diameter of the nozzle assembly is at least twice as large as the second inner diameter.

11. 11. The apparatus of claim 9 or 10, wherein the second inner diameter of the nozzle assembly is at least four times the size of the third inner diameter.

12. An apparatus according to any one of claims 9 to 11, wherein the length of the intermediate portion of the nozzle assembly is between 5 and 15 mm.

13. 13. The apparatus of any one of claims 9 to 12, wherein the organ pipe cavitator of the nozzle assembly is configured to generate a cavitating jet having a Strouhal number of between 0.2 and 0.

6.

14. An apparatus as described in any one of claims 9 to 13, wherein the nozzle assembly is configured to deliver a first flow of fluid through a cavitation peening nozzle and a second flow of fluid concentrically flowing around the first flow through an outer nozzle, the first flow being delivered at a higher pressure than the second flow.

15. 14. The device of any one of claims 9 to 13, wherein the nozzle assembly further has a cross-sectional area of ​​the distal opening that is 10 to 30% smaller than the cross-sectional area of ​​the proximal opening.

16. 16. The apparatus of claim 9, wherein the outlet portion of the nozzle assembly is defined by an inner wall of a convergent cavitator, the inner wall forming an angle of at least 8 degrees with respect to a central axis of the nozzle assembly.

17. 17. The apparatus of any one of claims 9 to 16, wherein the outlet portion of the nozzle assembly is frusto-conical.

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