A dual-working-condition multi-stage reinforced cavitation jet flow generating device and working method
By designing a dual-condition multi-stage enhanced cavitation device, integrating multi-stage structures on the same equipment to achieve flexible switching of operating modes, the problems of insufficient cavitation intensity and single operating conditions are solved, significantly improving cavitation effect and adaptability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIANGSU UNIV
- Filing Date
- 2026-04-16
- Publication Date
- 2026-07-14
AI Technical Summary
Existing cavitation devices have insufficient cavitation intensity, lack coordination and matching between multi-stage structures, suffer from serious ineffective energy dissipation, and have a single operating mode that cannot be freely switched on the same equipment.
The design incorporates a dual-condition, multi-stage enhanced cavitation generator. By combining low-speed and high-speed flow channels, it enables free switching between submerged and non-submerged operating conditions. Furthermore, it integrates multiple structures such as turbulence grids, rotating blades, inclined hole baffles, reverse spiral blades, and bellows nozzles into a single device, forming a multi-stage flow field control chain that combines disturbance and rotational direction conversion.
It significantly enhances cavitation intensity, enables flexible switching of operating modes, increases cavitation bubble generation density and collapse energy, has a compact and highly adaptable structure, and avoids ineffective energy dissipation.
Smart Images
Figure CN122377652A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of cavitation jet application technology, specifically to a dual-condition multi-stage enhanced cavitation generator and its operating method. Background Technology
[0002] Cavitation is a physical process in which cavitation bubbles are generated when the internal pressure of a liquid drops sharply below its saturated vapor pressure. These bubbles then collapse instantaneously in the pressure recovery zone, releasing high-intensity shock waves and microjets. This phenomenon can be effectively utilized for material forming and surface modification, offering high processing efficiency and environmental friendliness.
[0003] Existing cavitation generation methods mainly fall into three categories: contraction-type structures are simple but have low cavitation intensity, typically requiring multiple stages in series to meet requirements; swirling structures generate low-pressure zones through vortices, improving cavitation effects, but the swirling flow attenuates significantly along the flow direction, making it difficult to maintain continuous turbulent pulsations in the cavitation core region; shear-type structures generate intense cavitation but require two independent water supply systems, resulting in high equipment complexity. More importantly, existing devices share the following common limitations: cavitation enhancement methods are singular, and there is a lack of synergistic matching between multi-stage structures, easily leading to ineffective energy dissipation. Furthermore, existing devices are usually fixed to a single operating mode at the outlet: submerged systems are suitable for closed reaction systems, while non-submerged systems are suitable for open operations, and the two modes cannot be freely switched on the same device. Summary of the Invention
[0004] To address the shortcomings of existing technologies, this invention provides a dual-condition multi-stage enhanced cavitation generator and method. By designing low-speed and high-speed flow channels, it is possible to freely switch between the two conditions, resulting in strong adaptability to different operating conditions.
[0005] The present invention achieves the above-mentioned technical objectives through the following technical means.
[0006] A dual-condition multi-stage enhanced cavitation jet generator includes a high-pressure water pipe, a first connecting pipe, and a nozzle housing. The first connecting pipe is detachably connected to the high-pressure water pipe and the nozzle housing at both ends. A turbulence-inducing grid and rotating blades are sequentially arranged between the outlet end of the high-pressure water pipe and the inlet end of the first connecting pipe, wherein the rotating blades can rotate relative to the first connecting pipe under the action of water flow. A connector is provided at the outlet section of the first connecting pipe, supporting an inlet pipe. A second connecting pipe is connected to the outlet end of the inlet pipe, and a [missing information - likely a design feature] is provided at the outlet end of the second connecting pipe. A contraction tube is connected to the inlet end of a bellows nozzle, and the distance between the nozzle housing and the outlet end of the bellows nozzle is adjustable. Through holes are provided on the inlet tube, the second connecting tube, the contraction tube, and the bellows nozzle, and these through holes are coaxial. The through holes and the outlet on the nozzle housing are coaxial to form a high-speed flow channel. A low-speed flow channel is formed between the inner cavity of the nozzle housing and the second connecting tube, the contraction tube, and the bellows nozzle. A control device controls the motor to rotate the nozzle housing, adjusting the distance between the nozzle housing and the bellows nozzle to open and close the outlet of the low-speed flow channel.
[0007] In the above scheme, the diameter of the inlet end of the inlet pipe is larger than the diameter of the outlet end, and the diameter of the outlet end is the same as the diameter of the inlet end of the second connecting pipe.
[0008] In the above scheme, a baffle is provided at the connection between the inlet pipe and the second connecting pipe; several inclined through holes are opened around the center of the baffle, and the water flows through the inclined through holes to form a rotating flow and a negative pressure zone.
[0009] In the above scheme, the ratio of the total area of the plane containing the inclined through hole to the cross-sectional area of the baffle is 0.3 to 0.6; the inclined through hole is tangent to the baffle, and the inclination angle is 30° with the axis.
[0010] In the above scheme, the diameter of the outlet end of the second connecting pipe is larger than the diameter of the inlet end, and a spiral blade is provided inside the outlet end.
[0011] In the above scheme, the leading edge of the spiral blade is rounded, the rotation angle is 30°, and the rotation direction is opposite to that of the rotating flow. When the rotating flow passes by, it generates reverse shear, strongly disturbs the boundary layer, enhances turbulent pulsation, further reduces local pressure, and promotes the generation of cavitation bubbles.
[0012] In the above scheme, the two ends of the spiral blade are positioned by retaining rings.
[0013] In the above scheme, a connector is provided on the outer ring of the inlet pipe. The small end of the connector is detachably connected to the outer wall of the inlet pipe, and the large end is detachably connected to the first connecting pipe. Several ribs are provided between the two connecting rings at the beginning and end of the connector to enhance the strength and stability of the structure.
[0014] In the above scheme, a groove is formed at the end of the nozzle housing where it connects with the bellows nozzle; a rubber ring is built into the groove for sealing.
[0015] The operating method of the dual-condition multi-stage enhanced cavitation jet generator includes the following submerged operating mode and non-submerged operating mode:
[0016] According to the working conditions, operate the control device to control the motor to rotate the nozzle housing, adjust the size of the low-speed flow channel outlet, and realize the switching of working mode.
[0017] Submerged operating mode: High-pressure fluid flows through high-pressure water pipes, passing through turbulence grids and rotating blades, forming a large number of uniformly distributed cavitation nuclei; then, part of the high-pressure jet enters the inlet pipe, while the remaining fluid enters the low-speed flow channel through the gap between the first connecting pipe and the inlet pipe; after entering the high-speed flow channel, the jet flows through baffles to initially form a rotating flow, and fully develops in the straight section of the second connecting pipe, initially forming a stable negative pressure zone; the fluid passes through the spiral blades, generating reverse shear, strongly disturbing the boundary layer, enhancing turbulent pulsation, further reducing local pressure and promoting cavitation bubble generation; then, the fluid enters the bellows nozzle through the contraction section, and the resonant cavity causes the cavitation jet to self-excite oscillate, giving the cavitation jet pulse characteristics; the generated cavitation bubbles develop steadily as the fluid flows through the throat and are ejected from the expansion section of the bellows nozzle.
[0018] Non-submerged operating mode: After the high-pressure water flow enters the low-speed flow channel through the gap between the first connecting pipe and the inlet pipe, it flows out from the gap between the nozzle shell and the bottom of the bellows nozzle, providing a submerged water environment for the cavitation jet.
[0019] The beneficial effects of this invention are:
[0020] 1. Significantly Enhanced Cavitation Intensity: This invention integrates a turbulence grid, rotating blades, oblique-hole baffles, reverse-flow spiral vanes, a contraction tube, and an organ-tube nozzle sequentially along the water flow direction, forming a multi-stage turbulence and multiple rotation direction conversion flow field control chain. The turbulence grid and rotating blades pre-disturb the incoming flow, increasing the density of cavitation nuclei in the fluid and making the cavitation nuclei uniformly distributed; the oblique-hole baffles convert the axial incoming flow into a rotating flow, forming low-pressure vortex nuclei in the connecting pipe; the reverse-flow spiral vanes rotate in the opposite direction to the upstream flow, generating a strong shear layer in the flow field, inducing local pressure pulsations and micro-vortices; the contraction tube accelerates the fluid, causing the static pressure to drop sharply below the saturated vapor pressure; the organ-tube nozzle further introduces periodic pressure pulsations, promoting the generation and violent collapse of cavitation bubbles. The synergistic effect of each stage of the structure amplifies the cavitation intensity step by step, significantly improving the cavitation bubble generation density and collapse energy compared to a single contraction-type or single-stage swirling device.
[0021] 2. Flexible switching between dual operating modes and strong adaptability: This invention features a rotatable nozzle housing at the outlet end, equipped with a motor-driven control system. The motor drives the housing to rotate, causing axial displacement and precisely adjusting the relative position between the nozzle outlet and the housing. This allows for flexible switching between submerged and non-submerged cavitation modes on the same device: when the housing moves to the closed position of the low-speed flow channel outlet, the device is in submerged mode, where cavitation bubbles collapse within the liquid phase, and shock wave energy is concentrated in the closed system; when the housing moves downwards to a certain position from the nozzle outlet, the device is in non-submerged mode. These two modes can be freely switched on the same device according to actual needs without replacing equipment or disassembling components, significantly improving the device's versatility and adaptability to various scenarios.
[0022] 3. Compact structure and strong scalability: This invention integrates multi-stage disturbance, rotation conversion, acceleration throttling, and pulsating excitation within a single pipeline, eliminating the need for two independent water supply systems like shear-type cavitation devices. The overall structure is compact and occupies little space. Furthermore, the modular design of this invention, with threaded connections for all components, facilitates disassembly, allowing for the replacement or addition of different structural stages according to specific application scenarios.
[0023] 4. This invention solves the problem of the single working condition of existing cavitation nozzles, realizes flexible switching between submerged and non-submerged working conditions, and adds a multi-stage structure to enhance the cavitation effect, solving the problems of insufficient cavitation intensity and low efficiency of existing technologies. Moreover, the structure is simple, compact and easy to process and install. Attached Figure Description
[0024] Figure 1 A schematic diagram of a dual-condition multi-stage enhanced cavitation jet generator;
[0025] Figure 2 for Figure 1 A schematic diagram of the spoiler grille structure involved;
[0026] Figure 3 for Figure 1 A schematic diagram of the rotating blade structure involved;
[0027] Figure 4 for Figure 1 A schematic diagram of the baffle involved;
[0028] Figure 5 for Figure 1 A schematic diagram of the spiral plate structure involved;
[0029] Figure 6 This is a schematic diagram illustrating the principle of the present invention under non-flooding operating conditions.
[0030] Figure label:
[0031] 1-High-pressure water pipe; 2-Break screen; 3-Rotating blade; 4-First connecting pipe; 5-Connector; 6-Inlet pipe; 7-Baffle; 8-Second connecting pipe; 9-Spiral blade; 10-Baffle ring; 11-Rubber ring; 12-Bug nozzle; 13-Contraction tube; 14-Nozzle housing; 15-High-speed flow channel; 16-Low-speed flow channel; 17-Motor; 18-Control device; 19-Ball bearing; 20-Outer sleeve. Detailed Implementation
[0032] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.
[0033] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "axial," "radial," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.
[0034] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0035] Combined with appendix Figure 1As shown, a dual-condition multi-stage enhanced cavitation jet generator includes a cavitation generating component and a control system. The cavitation generating component includes a high-pressure water pipe 1, a turbulence grid 2, a rotating blade 3, a first connecting pipe 4, a connector 5, an inlet pipe 6, a baffle 7, a second connecting pipe 8, a retaining ring 10, a spiral blade 9, a contraction pipe 13, a bellows nozzle 12, and a nozzle housing 14. The first connecting pipe 4 is connected at its head to the tail of the high-pressure water pipe 1, and at its tail to the head of the nozzle housing 14. The connector 5 has a small connecting ring connected to the inlet pipe 6 and a large connecting ring connected to the tail of the first connecting pipe 4. The second connecting pipe 8 connects the inlet pipe 6 and the contraction pipe 13. The bellows nozzle 12 is connected to the contraction pipe 13. All connections are made using threaded connections.
[0036] The turbulence grille 2 is positioned upstream of the rotating blade 3 and the two are connected. It is also secured to the high-pressure water pipe 1 and the first connecting pipe 4 by key connections to prevent them from vibrating and shifting under the impact of high-pressure water flow.
[0037] The cross-section of the grid is airfoil-shaped. When water flows through it, the change in flow velocity generates low pressure, which improves the cavitation efficiency.
[0038] The rotating blade 3, as the inner sleeve, is combined with the ball bearing 19 and the outer sleeve 20 to form a rolling bearing structure, which enables the blade to rotate through the impact of the water flow. Based on the initial turbulence of the turbulence grid 2, a three-dimensional swirling agitation is formed, making the cavitation nuclei more evenly distributed in the water flow.
[0039] Connector 5 consists of two connecting rings of different diameters and several ribs; the smaller diameter connecting ring has an internal thread and connects to the high-speed water inlet pipe 6; the larger diameter connecting ring has an external thread and connects to the first connecting pipe 4; the number of ribs is set to 10 to enhance the strength and stability of the structure and prevent it from failing under the impact of high-pressure water flow; the cross-section of the ribs is airfoil-shaped, and the low pressure generated by the change in flow velocity when the water flows through it increases the cavitation nuclei in the low-speed water.
[0040] The inner wall of the tail end of the first connecting pipe 4 has a protrusion that reduces the inner diameter, preventing the connector 5 from falling off due to water flow impact and improving the stability of the structure.
[0041] The baffle 7 has an outer diameter of 20 mm and a thickness of 4 mm. Four inclined through holes are evenly opened at a distance of 4 mm from the center. The through holes are tangent to the baffle 7 and the inclination angle is 30° with the axis. The water flow through the through holes forms a swirling flow and creates a negative pressure zone. The ratio of the total opening area of the through holes to the cross-sectional area of the baffle 7 is controlled between 0.3 and 0.6 to prevent excessive pressure loss or weakening of the swirling effect.
[0042] The second connecting pipe 8 has two straight sections inside; the length-to-diameter ratio of the first straight section is 3-5, which allows the rotating flow to develop fully; the second straight section has a spiral blade 9 and a retaining ring 10, with the retaining ring 10 placed at both ends of the spiral blade 9 to hold it in place in the second straight section.
[0043] The leading edge of the spiral blade 9 is rounded, and the rotation angle is 30°. The rotation direction is opposite to that of the rotating flow. When the rotating flow passes by, it generates reverse shear, which strongly disturbs the boundary layer, enhances turbulent pulsation, further reduces local pressure, and promotes the generation of cavitation bubbles.
[0044] The inner diameter of the contraction tube 13 gradually decreases along the direction of fluid flow, and its contraction angle is 20°, which is used for further acceleration of the fluid.
[0045] The organ pipe nozzle 12 consists of a resonant cavity, a throat, and an expansion section in sequence from the direction of incoming flow; the resonant cavity is a constant diameter structure with an aspect ratio of 2; the throat has a diameter of 3 mm; and the expansion angle of the expansion section is 20° to ensure the stability of the cavitation cloud.
[0046] A groove is provided at the end of the nozzle housing 14 where it meets the bellows nozzle 12; a rubber ring 11 is installed in the groove to achieve a sealing effect under submerged conditions; both the groove and the rubber ring 11 have an inverted T-shaped cross section to prevent the rubber ring 11 from falling out of the groove during operation.
[0047] The motor 17 is controlled by the control device 18 to rotate the nozzle housing 14, thereby controlling the size of the outlet of the low-speed flow channel 16.
[0048] The specific working principle and process are as follows:
[0049] According to the working conditions, the operating control device 18 controls the motor 17 to rotate the nozzle housing 14, adjusts the size of the outlet of the low-speed flow channel 16, and realizes the switching of working conditions.
[0050] Submerged condition: High-pressure fluid flows through high-pressure water pipe 1, through turbulence grid 2 and rotating blades 3, forming a large number of uniformly distributed cavitation nuclei; then, part of the high-pressure jet enters inlet pipe 6, i.e., high-speed flow channel 15, while the rest enters low-speed flow channel 16 through the gap between the first connecting pipe 4 and inlet pipe 6; after entering high-speed flow channel 15, the jet flows through baffle 7 to initially form a rotating flow, and fully develops in the straight section of the connecting pipe, initially forming a stable negative pressure zone; the fluid passes through spiral blades 9, generating reverse shear, strongly disturbing the boundary layer, enhancing turbulent pulsation, further reducing local pressure and promoting cavitation bubble generation; then the fluid enters the bellows nozzle 12 through the contraction section, and the resonant cavity causes the cavitation jet to self-excite oscillate, giving the cavitation jet pulse characteristics; the generated cavitation bubbles develop steadily as the fluid flows through the throat and are ejected from the nozzle expansion section.
[0051] Non-submerged operating conditions: See Figure 5After the high-pressure water flows into the low-speed flow channel 16 through the gap between the first connecting pipe 4 and the inlet pipe 6, it flows out from the gap between the nozzle housing 14 and the bottom of the bellows nozzle 12, providing a flooded water environment for the cavitation jet.
[0052] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0053] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.
Claims
1. A dual-condition multi-stage enhanced cavitation jet generator, characterized in that, The system includes a high-pressure water pipe (1), a first connecting pipe (4), and a nozzle housing (14); the two ends of the first connecting pipe (4) are detachably connected to the high-pressure water pipe (1) and the nozzle housing (14), respectively; a baffle grille (2) and a rotating blade (3) are arranged sequentially between the outlet end of the high-pressure water pipe (1) and the inlet end of the first connecting pipe (4), wherein the rotating blade (3) can rotate relative to the first connecting pipe (4) under the action of water flow; a connector (5) is provided at the outlet section of the first connecting pipe (4), the connector (5) supports an inlet pipe (6), the outlet end of the inlet pipe (6) is connected to a second connecting pipe (8), the outlet end of the second connecting pipe (8) is provided with a shrink tube (13), and the shrink tube (13) is connected to a bellows pipe. The distance between the inlet end of the nozzle (12), the nozzle housing (14), and the outlet end of the bellows nozzle (12) is adjustable; the inlet pipe (6), the second connecting pipe (8), the contraction pipe (13), and the bellows nozzle (12) are all provided with through holes and are coaxial with each other. The through holes and the outlet on the nozzle housing (14) are coaxial to form a high-speed flow channel (15); the inner cavity of the nozzle housing (14) and the second connecting pipe (8), the contraction pipe (13), and the bellows nozzle (12) form a low-speed flow channel (16); the motor (17) is controlled by the control device (18) to rotate the nozzle housing (14) and adjust the distance between the nozzle housing (14) and the bellows nozzle (12) to realize the opening and closing of the outlet of the low-speed flow channel (16).
2. The dual-condition multi-stage enhanced cavitation jet generator according to claim 1, characterized in that, The diameter of the inlet end of the inlet pipe (6) is greater than the diameter of the outlet end, and the diameter of the outlet end is the same as the diameter of the inlet end of the second connecting pipe (8).
3. The dual-condition multi-stage enhanced cavitation jet generator according to claim 1, characterized in that, A baffle (7) is provided at the connection between the inlet pipe (6) and the second connecting pipe (8); several inclined through holes are provided around the center of the baffle (7), and the water flows through the inclined through holes to form a rotating flow and a negative pressure zone.
4. The dual-condition multi-stage enhanced cavitation jet generator according to claim 1, characterized in that, The diameter of the outlet end of the second connecting pipe (8) is larger than the diameter of the inlet end, and a spiral blade (9) is provided inside the outlet end.
5. The dual-condition multi-stage enhanced cavitation jet generator according to claim 4, characterized in that, The leading edge of the spiral blade (9) is rounded, the rotation angle is 30°, and the rotation direction is opposite to that of the rotating flow. When the rotating flow passes by, it generates reverse shear, strongly disturbs the boundary layer, enhances turbulent pulsation, further reduces local pressure, and promotes the generation of cavitation bubbles.
6. The dual-condition multi-stage enhanced cavitation jet generator according to claim 4, characterized in that, The spiral blade (9) is positioned at both ends by retaining rings (10).
7. The dual-condition multi-stage enhanced cavitation jet generator according to claim 6, characterized in that, The ratio of the total area of the plane containing the inclined through hole to the cross-sectional area of the baffle (7) is 0.3 to 0.6; the inclined through hole is tangent to the baffle (7) and the inclination angle is 30° with the axis.
8. The dual-condition multi-stage enhanced cavitation jet generator according to claim 1, characterized in that, The inlet pipe (6) is provided with a connector (5) on its outer ring. The small end of the connector (5) is detachably connected to the outer wall of the inlet pipe (6), and the large end is detachably connected to the first connecting pipe (4). Several ribs are provided between the two connecting rings at the beginning and end of the connector (5) to enhance the strength and stability of the structure.
9. The dual-condition multi-stage enhanced cavitation jet generator according to claim 1, characterized in that, A groove is provided at the end of the nozzle housing (14) where it meets the bellows nozzle (12); a rubber ring (11) is built into the groove for sealing.
10. The operating method of the dual-condition multi-stage enhanced cavitation jet generator according to any one of claims 1-9, characterized in that, The following are included: flooded operating conditions and non-flooded operating conditions: According to the working conditions, the operating control device (18) is used to control the motor (17) to rotate the nozzle housing (14), adjust the size of the low-speed flow channel (16) outlet, and realize the switching of working mode; Submerged operating mode: High-pressure fluid flows through high-pressure water pipe (1), through turbulence grid (2) and rotating blade (3), forming a large number of uniformly distributed cavitation nuclei; then the high-pressure jet part enters the inlet pipe (6), and the remaining part of the fluid enters the low-speed flow channel (16) through the gap between the first connecting pipe (4) and the inlet pipe (6); after the jet enters the high-speed flow channel (15), it flows through the baffle (7) to initially form a rotating flow, and fully develops in the straight section of the second connecting pipe (8), initially forming a stable negative pressure zone; the fluid passes through the spiral blade (9), generating reverse shear, strongly disturbing the boundary layer, enhancing turbulent pulsation, further reducing the local pressure and promoting the generation of cavitation bubbles; then the fluid enters the bellows nozzle (12) through the contraction section, and the resonant cavity makes the cavitation jet self-excited oscillation, giving the cavitation jet pulse characteristics; after the generated cavitation bubbles develop stably with the fluid flowing through the throat, they are ejected from the expansion section of the bellows nozzle (12); Non-submerged operating mode: After the high-pressure water flow enters the low-speed flow channel (16) through the gap between the first connecting pipe (4) and the inlet pipe (6), it flows out from the gap between the nozzle shell (14) and the bottom of the bellows nozzle (12), providing a submerged water environment for the cavitation jet.