Solar micro-nano aerator

Abstract

The application discloses a solar micro-nano aerator, and belongs to the technical field of water treatment and water body restoration equipment, which comprises a floating platform, wherein a solar energy supply unit, a micro-nano bubble generating unit and a control unit are arranged on the floating platform; the micro-nano bubble generating unit comprises a liquid inlet chamber, a Venturi contraction section, a throat and a throttling expansion cavity with gradually decreasing inner diameters, which are sequentially connected along the water flow direction; the liquid inlet chamber is connected with an air inlet pipe extending above the water surface, and an impeller is rotatably arranged in the liquid inlet chamber; at least two groups of variable-pitch helical guide vanes are arranged in the Venturi contraction section in series along the axial direction, and the pitch of the variable-pitch helical guide vanes gradually decreases along the water flow direction; a throttling orifice plate with gradually decreasing central throttling orifice diameters is arranged between adjacent throttling expansion cavities, and a bubble cutting unit is arranged at the outlet end of the diffusion section. The bubble particle size of the application can reach submicron level, and the application is suitable for black and odorous water body treatment, lake ecological restoration and aquaculture oxygenation.

Description

Technical Field

[0001] This invention relates to the field of water treatment and water body restoration equipment technology, specifically to a solar-powered micro-nano aerator, which is suitable for scenarios such as black and odorous water body treatment, lake ecological restoration, and aquaculture oxygenation. Background Technology

[0002] Solar-powered aerators are water treatment devices that use solar energy. They are mainly used in water bodies such as rivers, lakes, and reservoirs where power supply is insufficient. They achieve water oxygenation, pollutant degradation, and ecological restoration through methods such as layering aeration and flow circulation.

[0003] With the acceleration of urbanization, the demand for efficient oxygenation equipment for the treatment of black and odorous water bodies in rivers, the control of eutrophication in lakes, and high-density aquaculture is becoming increasingly urgent. Existing solar aeration devices have gradually revealed the following shortcomings: Most existing devices adopt microporous diffuser discs or single-stage Venturi structures; among them, the bubble particle size of microporous diffuser type is usually in the hundreds of micrometers to millimeters, with low oxygen utilization rate, and the micropores are easily blocked by impurities and biofilms during long-term operation; the single-stage Venturi type relies on single negative pressure shear, and the bubble particle size increases sharply under high flow conditions, and the particle size cannot be controlled; in addition, although existing technologies disclose multi-stage throttling orifice pressurized dissolution and depressurized release structures (such as the disclosure number CN223496315U), and rely on the "pressurized dissolution-depressurized precipitation" process to generate microbubbles, this process is discontinuous, has high energy consumption, and does not combine the swirling shear and cavitation refinement mechanisms. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a solar-powered micro-nano aerator with small and adjustable bubble particle size, and further enable the aerator to have the synergistic purification functions of oxygenation and photocatalytic advanced oxidation.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a solar-powered micro-nano aerator, comprising a floating platform, a solar energy supply unit, a micro-nano bubble generating unit, and a control unit; the micro-nano bubble generating unit comprises an inlet chamber, a Venturi contraction section, a throat, and a throttling expansion chamber with progressively decreasing inner diameter, connected sequentially along the water flow direction; the inlet chamber is connected to an air inlet pipe extending above the water surface, and an impeller is rotatably installed inside the inlet chamber; at least two sets of variable pitch spiral guide vanes are connected in series along the axial direction within the Venturi contraction section, the pitch of which gradually decreases along the water flow direction; a throttling orifice plate with progressively decreasing central throttling orifice diameter is provided between adjacent throttling expansion chambers, and a bubble cutting unit is provided at the outlet end of the diffusion section. At this point, when the gas and liquid enter the micro / nano bubble generating unit, the first-stage guide vanes induce swirling flow in the gas-liquid mixture, the intermediate-stage guide vanes further develop the swirling flow, and the final-stage guide vanes enhance shearing. A negative pressure is formed at the throat, inducing cavitation, thus causing the gas-liquid mixture to undergo a repeated process of "pressurized dissolution—throttling and sudden expansion—depressurized release" within each stage of the chamber. Simultaneously, the negative pressure at the throat enables gas self-absorption. Therefore, the triple refinement mechanism of swirling shearing, throat cavitation, and multi-stage depressurization release acts on the bubbles step by step, refining the bubble size to the micrometer and submicrometer scale, which can be controlled by the rotation speed and the number of stages.

[0006] Furthermore, a photocatalytic synergistic unit is installed at the outlet end of the diffusion section of the micro / nano bubble generating unit. This unit includes a transparent flow guide hood covering the outlet section of the diffusion section, with the inner wall of the hood coated with a TiO2 nanotube array photocatalytic coating. The unit also includes a light guide column and a diffuser prism. The upper end of the light guide column has a light-collecting section located on the upper part of the floating platform. The lower end of the light guide column extends into the top of the transparent flow guide hood through an opening in the side wall and connects to the diffuser prism, which diffuses the light into the bubble generating area within the transparent flow guide hood. Thus, the aerator can guide light from above the water surface into the light-guiding structure (light guide column and diffuser prism) inside the transparent flow guide hood, enabling the micro / nano bubbles and photocatalysis to synergistically degrade organic matter, achieving integrated oxygenation and advanced oxidation.

[0007] Furthermore, an annular flow guide gap is provided between the transparent flow guide hood and the outer wall of the outlet end of the diffusion section of the micro-nano bubble generating unit. When the bubbles flow through the annular flow guide gap, they will rub and collide with the hood wall, which will enhance the double layer charge separation, increase the bubble zeta potential, and inhibit bubble aggregation.

[0008] Furthermore, a fully sealed drive unit is provided between the floating platform and the micro / nano bubble generating unit.

[0009] Furthermore, the fully sealed drive unit includes a sealed chamber, a submersible motor located inside the sealed chamber, and a magnetic coupler located at the bottom of the sealed chamber. The sealed chamber is fixed below the floating platform by a support column. The magnetic coupler includes an active magnetic rotor, a driven magnetic rotor, and an isolation sleeve fixed at the bottom opening of the sealed chamber. The active magnetic rotor is drivenly connected to the output shaft of the submersible motor and is located inside the isolation sleeve. The driven magnetic rotor is rotatably mounted on the outside of the isolation sleeve through an auxiliary bearing and is connected to the driven output shaft through a torque adaptive buffer. The driven output shaft is drivenly connected to the impeller of the micro / nano bubble generating unit.

[0010] Furthermore, the bubble cutting unit includes at least two layers of arc-shaped thin plates arranged at intervals along the flow direction, with the spacing between each layer decreasing along the flow direction. The surface of the arc-shaped thin plates is coated with a superhydrophobic nano-coating. At this time, the arc-shaped thin plates perform multi-stage mechanical shearing on the bubbles, and the superhydrophobic surface reduces the bubble adhesion, enabling the bubbles to quickly desorb and refine, and preventing pore blockage and bio-attachment.

[0011] Furthermore, the inner wall of the throttling expansion cavity and / or the inner wall of the diffusion section are coated with a superhydrophobic nano-coating, which is a micro-nano composite structure coating with a contact angle with water greater than 150° and a roll-off angle less than 10°.

[0012] Furthermore, the solar power unit includes a dual-axis tracking mechanism installed on the floating platform and a photovoltaic panel installed on the dual-axis tracking mechanism, with the photovoltaic panel electrically connected to a battery pack and a controller.

[0013] Furthermore, the inlet of the air intake pipe above the water surface is equipped with a rain cap and a filter, and a one-way valve is installed on the air intake pipe; a filter screen is installed at the inlet of the liquid inlet chamber.

[0014] As can be seen from the above technical solutions, the present invention has the following advantages: 1. This invention sequentially superimposes the effects of variable-pitch swirling shearing, throat cavitation, and multi-stage throttling expansion chambers, resulting in pressurized dissolution and depressurized release. Unlike single-stage Venturi or single-stage throttling structures, this invention can control the median bubble diameter down to 0.8 μm, with bubbles smaller than 10 μm accounting for 91% of the total. The standard oxygen mass transfer rate constant K... La It is more than twice as efficient as a single-stage Venturi particle size analyzer, and the particle size can be controlled within the range of submicron to tens of micron by adjusting the motor speed. 2. This invention encloses the submersible motor in a welded sealed chamber, and the power is transmitted non-contactly through the chamber via a magnetic coupler, completely eliminating the leakage path of the mechanical shaft seal; the torque adaptive buffer absorbs the impact of starting and coating fluctuations, avoiding demagnetization of the magnetic rotor; the maintenance-free period of continuous underwater operation of the whole machine is increased from the conventional 3 months (shaft seal replacement) to more than 12 months, with high safety; 3. This invention utilizes a light guide column to introduce sunlight into a transparent flow guide hood to excite a TiO2 nanotube array, which works in synergy with the ·OH effect generated by the rupture of micro-nano bubbles. This increases the degradation rate of typical pollutants such as Rhodamine B by more than 2 times compared to simple aeration, without the need for external reagents or independent oxidation equipment. 4. This invention uses a non-porous, gill-shaped arc-shaped thin plate instead of a microporous plate, combined with a superhydrophobic coating and an inlet filter screen, which can fundamentally avoid micropore clogging and ensure long-term stable operating pressure differential. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments are briefly introduced below: Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention; Figure 2 This is a schematic diagram of the solar energy supply unit in an embodiment of the present invention (the dashed lines in the diagram represent light rays). Figure 3 This is a cross-sectional view of the fully sealed drive unit in an embodiment of the present invention; Figure 4 This is a cross-sectional view of the micro / nano bubble generating unit in an embodiment of the present invention; Figure 5 This is a partial cross-sectional view of the photocatalytic synergistic unit in an embodiment of the present invention (the dashed lines in the figure represent light rays).

[0016] Explanation of reference numerals in the attached drawings: 1. Floating platform; 10. Floating box; 2. Solar power unit; 20. Photovoltaic panel; 21. Dual-axis tracking mechanism; 22. Controller; 23. Battery pack; 24. Horizontal rotary drive motor; 25. Rotary platform; 26. Photovoltaic support; 27. Pitch axis; 28. Electric pitch push rod; 3. Sealed chamber; 30. Submersible motor; 31. Power cable; 31a. Cable sealing joint; 32. Continuous weld; 4. Magnetic coupler; 40. Active magnetic rotor; 41. Driven magnetic rotor; 42. Isolation sleeve; 43. Torque adaptive buffer; 44. Driven output shaft; 45. Auxiliary 5. Bearing; 6. Micro / nano bubble generating unit; 7. Liquid inlet; 8. Air inlet pipe; 9. Venturi constriction section; 10. Variable pitch spiral guide vane; 11. Throat; 12. Throttling expansion chamber; 13. Throttling orifice plate; 14. Diffusion section; 15. Small pitch shearing vane; 16. Transparent guide hood; 17. TiO2 nanotube array photocatalytic coating; 18. Light guide column; 19. Diffusion prism; 20. Bubble cutting unit; 21. Superhydrophobic nano coating; 22. Control unit; 33. Dissolved oxygen sensor; 44. Light sensor; 55. Support column; 66. Motor output shaft; 77. Impeller; 88. Liquid inlet chamber. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0018] Example 1 like Figure 1 As shown, this embodiment provides a first type of solar-powered micro-nano aerator, which mainly includes a floating platform 1, a solar power supply unit 2, a fully sealed drive unit, a micro-nano bubble generating unit 5, and a control unit 9.

[0019] The floating platform 1 consists of two sets of pontoons 10 and a supporting frame, with a span of 2.4m. Specifically, each pontoon 10 is a hollow, closed box made of high-density polyethylene through integral blow molding, with internal reinforcing ribs and mounting holes pre-set on the top and side walls. The supporting frame is a rectangular frame welded from 316L stainless steel profiles, and its bottom sides have slots that match the shape of the pontoons 10. Thus, during assembly, the two sets of pontoons 10 can be respectively embedded into the slots on both sides of the bottom of the supporting frame and locked in place with bolts, thereby forming a rigidly connected integrated floating structure between the pontoons 10 and the supporting frame.

[0020] like Figure 2 As shown, the solar power supply unit 2 includes a photovoltaic panel 20, a controller 22, and a battery pack 23. Specifically, the photovoltaic panel 20 preferably consists of two 450W monocrystalline silicon photovoltaic panels (total installed capacity 900W), the controller 22 preferably uses an MPPT (Maximum Power Point Tracking) controller, and the battery pack 23 preferably uses a 48V / 100Ah lithium iron phosphate battery pack. The two photovoltaic panels 20 are connected in parallel and electrically connected to the battery pack 23 through the controller 22, which enables maximum power point tracking and manages the charging and discharging of the battery pack 23.

[0021] Furthermore, as a preferred embodiment, this embodiment also adds a dual-axis tracking mechanism 21 to the solar energy functional unit 2, enabling the photovoltaic panel 20 to track the sun in two degrees of freedom: horizontal azimuth and vertical pitch, with the cooperation of the dual-axis tracking mechanism 21. Specifically, the dual-axis tracking mechanism 21 includes a rotary platform 25 rotatably mounted on the top of the support frame. A horizontal rotary drive motor 24 is connected to one side of the rotary platform 25, allowing it to rotate horizontally around a vertical axis under the action of the horizontal rotary drive motor 25. A photovoltaic bracket 26 is fixedly mounted on the top of the rotary platform 25, and the photovoltaic bracket 26 is hinged to one side of the photovoltaic panel 20 via a pitch axis 27. Simultaneously, an electric pitch push rod 28 is hinged between the photovoltaic bracket 26 and the back of the photovoltaic panel 20, allowing the electric pitch push rod 28 to extend and retract, thereby pushing the photovoltaic panel 20 to rotate around the pitch axis 27 in a vertical plane, thus adjusting the pitch angle of the photovoltaic panel 20. Furthermore, the specific tracking control strategy can adopt the solar motion trajectory algorithm and combine it with the light sensor 91 arranged on the surface of the photovoltaic panel 20 for real-time deviation correction, so that the tracking control accuracy can reach ±2°, thereby ensuring that the photovoltaic panel 20 can maintain high light-receiving efficiency in different seasons and times, and provide a continuous and stable power guarantee for the coating on the floating platform 1.

[0022] like Figure 3 As shown, the fully sealed drive unit includes a sealed chamber 3 and a drive component disposed inside the sealed chamber 3. Specifically, the sealed chamber 3 is connected to the floating platform 1 via a support column 11, and its material is preferably 316L stainless steel with a wall thickness of 8mm. In this embodiment, a cable sealing joint 31a is also provided at its top for the power cable 31 to pass through the chamber. After the power cable 31 is inserted, insulating glue is applied to the joint to achieve a seal. The drive component includes a submersible motor 30 fixedly installed inside the sealed chamber 3. This motor is a 48V brushless DC motor with a rated power of 750W and an output speed that is steplessly adjustable within the range of 500–3000 r / min.

[0023] A magnetic coupler 4 is installed at the bottom of the sealed chamber 3. The magnetic coupler 4 includes an isolation sleeve 42 welded and fixed to the bottom opening of the sealed chamber 3. The isolation sleeve 42 has a cup-shaped structure and a wall thickness of 1.5 mm. The material is selected from Hastelloy C, 276 or engineering plastic PEEK. Preferably, the joint between the isolation sleeve 42 and the bottom opening of the sealed chamber 3 is a continuous weld 32. The continuous weld 32 and the cable sealing joint 31a together make the sealed chamber 3 a fully sealed cavity with a protection level of IP68, which fundamentally eliminates the leakage path of the traditional shaft seal structure. At the same time, the motor output shaft 12 of the submersible motor 30 extends downward into the isolation sleeve 42, and a neodymium iron boron N42 active magnetic rotor 40 is fixedly installed at its shaft end. A driven magnetic rotor 41 is sleeved on the outside of the isolation sleeve 42. The active magnetic rotor 40 and the driven magnetic rotor 41 are opposite to each other. The magnetic field between them passes through the wall of the isolation sleeve 42 to achieve non-contact torque transmission. The driven magnetic rotor 41 is supported on the outside of the isolation sleeve 42 by two auxiliary bearings 45 (preferably deep groove ball bearings), and the lower end of the isolation sleeve 42 is connected to the driven output shaft 44 via a torque adaptive buffer 43. The torque adaptive buffer 43 is made of polyurethane and is used to absorb the impact load during the transmission process.

[0024] like Figure 4 As shown, the micro / nano bubble generating unit 5 is connected to the driven output shaft 44 via its input end at its central axis and rotates synchronously with the driven output shaft 44. Furthermore, the micro / nano bubble generating unit 5, along the water flow direction, sequentially includes an inlet chamber 14, a Venturi contraction section 52, a throat 54, a three-stage throttling expansion chamber 55, and a diffusion section 57. The inlet 50 of the inlet chamber 14 is equipped with a 3mm pore size filter screen for coarse filtration of the absorbed liquid. Simultaneously, an air inlet pipe 51 is connected to the side wall of the inlet chamber 14. The air inlet of the air inlet pipe 51 is 300mm above the water surface and, along the airflow direction, is sequentially equipped with a rain cap, filter cotton, and a one-way valve to prevent water backflow and filter impurities in the intake air. The Venturi contraction section 52 has a contraction angle of 18° and a contraction ratio of 4:1. The Venturi contraction section 52 has three sets of variable pitch helical guide vanes 53 arranged in series along the axial direction: the first-stage guide vane has a pitch of 40 mm and is used to induce the fluid to form a swirling flow; the intermediate-stage guide vane has a pitch of 28 mm and is used to further develop the swirling flow; the final-stage guide vane has a pitch of 14 mm and is used to enhance shearing. Each set of variable pitch helical guide vanes has four vanes.

[0025] The throat 54 has a diameter of 16 mm and an aspect ratio of 3. This allows the fluid velocity to rise above 12 m / s when flowing through the throat 54, reducing the local static pressure below the vaporization pressure of water, thus inducing cavitation and creating a negative pressure at the throat 54 to draw in outside air, achieving gas-liquid mixing. Downstream of the throat 54 is a three-stage throttling expansion chamber 55. The inner diameters of each stage of the throttling expansion chamber 55 decrease sequentially along the flow direction: 60 mm, 45 mm, and 32 mm. Throttling orifice plates 56 are installed between adjacent stages, with the diameters of the central throttling orifices of each orifice plate 56 decreasing sequentially along the flow direction: 20 mm, 17 mm, and 14 mm. Furthermore, the final stage throttling expansion chamber 55 is equipped with small-pitch shearing blades with a pitch of 8 mm for further shearing of the air bubbles. Based on this, the gas-liquid mixture undergoes a cyclic process of "sudden expansion - depressurization and precipitation - throttling and recompression - expansion and precipitation again" in each chamber, and the bubbles are refined step by step.

[0026] Downstream of the throttling expansion cavity 55 is a diffusion section 57 with a diffusion angle of 10°. Furthermore, the outlet end of the diffusion section 57 is equipped with a biomimetic gill-like bubble cutting unit 7. This bubble cutting unit 7 comprises five layers of arc-shaped thin plates, each 0.4 mm thick and made of 316L stainless steel. The spacing between adjacent arc-shaped thin plates decreases from 8 mm to 3 mm along the flow direction, thereby performing multi-stage shearing and cutting on the bubbles flowing out of the diffusion section 57, further reducing the bubble size.

[0027] Moreover, as a preferred embodiment, the inner wall of the diffusion section 57 and the surface of the arc-shaped thin plate 70 are coated with a superhydrophobic nano-coating 8. The superhydrophobic nano-coating 8 is prepared by using SiO2 micro-nano composite particles combined with fluorosilane modification. The water contact angle can reach 162° and the roll-off angle is only 7°, which can effectively inhibit the adhesion of bubbles on the wall surface and promote the rapid detachment of microbubbles.

[0028] Based on this, when using this embodiment for aeration operations, the working process is as follows: During the day, the photovoltaic panel 20 charges the battery pack 23 and supplies power to the system via the controller 22; the control unit 9 drives the submersible motor 30, and the power is transmitted non-contactly to the impeller 13 via the magnetic coupler (active magnetic rotor 40 → isolation sleeve 42 → driven magnetic rotor 41); the impeller pumps water into the inlet chamber 14 through the inlet port 50, and the negative pressure in the throat 54 draws in air through the air inlet pipe 51; the gas-liquid mixture is sequentially subjected to swirling shearing by variable pitch blades, cavitation in the throat, and repeated pressurization and depressurization release in the three-stage throttling expansion chamber 55, and the bubbles are gradually refined to the micron / submicron level; then, it is subjected to multi-stage mechanical shearing by the gill-type arc-shaped thin plate, and rapidly desorbed on the superhydrophobic surface, and finally released into the water body from the inner cavity, and continuously transferred mass and oxygenated during the slow rise of the micro-nano bubbles.

[0029] Meanwhile, the control unit is electrically connected to the light sensor and the dissolved oxygen sensor, and is configured to: reduce the driving power of the submersible motor and switch to the small particle size energy-saving aeration mode when the light intensity is lower than the first preset threshold; increase the driving power to full load when the dissolved oxygen value is lower than the preset lower limit; and enter sleep mode when the dissolved oxygen value is higher than the preset upper limit.

[0030] Example 2 This second embodiment provides a second type of solar-powered micro-nano aerator, which differs from the first embodiment in that: the second embodiment adds a photocatalytic synergistic unit on the basis of the first embodiment, thereby introducing photocatalytic oxidation at the same time as the generation of micro-nano bubbles, further enhancing the degradation capacity of organic pollutants in water.

[0031] Specifically, such as Figure 5 As shown, in this embodiment, a transparent guide hood 6 is provided on the outside of the water outlet end of the diffusion section 57 of the micro-nano bubble generating unit 5. The transparent guide hood 6 is made of quartz glass, and its inner wall is coated with a TiO2 nanotube array photocatalytic coating 60 by anodizing. The TiO2 nanotube array photocatalytic coating 60 has a tube diameter of 50nm, a tube length of 1.2μm, and a crystal form of anatase.

[0032] The photocatalytic synergistic unit also includes a light guide post 61 and a diffuser prism 62. The light guide post 61 is a quartz fiber bundle with a numerical aperture of 0.37. A light-collecting section is located at the upper end of the light guide post 61, situated on the upper part of the floating platform 1, and rotates synchronously with the orientation of the photovoltaic panel 20 to always face the sun. The lower end of the light guide post 61 extends into the top of the transparent shroud 6 through an opening in the side wall of the top of the shroud, and is connected to the diffuser prism 62. The diffuser prism 62 is made of frosted quartz material and is used to diffuse and uniformly irradiate the bubble generation area within the transparent shroud 6.

[0033] Based on this, when this embodiment is in operation, on the one hand, hydroxyl radicals (·OH) are generated during the shrinkage and rupture of micro-nano bubbles; on the other hand, superoxide radicals (·O2) are generated when the TiO2 coating is excited by light. - hydroxyl radicals (·OH) and photogenerated holes (h) + The aforementioned active species together form a synergistic oxidation system within the transparent flow guide shroud 6, efficiently degrading organic matter in the water. Simultaneously, the supersaturated dissolved oxygen carried by the micro-nano bubbles prolongs the survival time of active oxygen, further enhancing the oxidation effect.

[0034] In addition, this embodiment maintains a 2mm annular flow guide gap between the transparent flow guide shroud 6 and the outer wall of the water outlet end of the diffuser section 57. When the bubbles flow through this annular gap, they will rub and collide with the shroud wall, which has a high dielectric constant, thereby strengthening the charge separation of the double layer, increasing the absolute value of the bubble zeta potential, inhibiting the aggregation and growth of bubbles, and maintaining the high dispersion state of the bubbles.

[0035] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention, such as setting the throttling expansion cavity to two or four stages, changing the photocatalytic coating material, or adjusting the photovoltaic panel power configuration, should be included within the protection scope of the present invention.

Claims

1. A solar-powered micro / nano aerator, comprising a floating platform (1), wherein a solar energy supply unit (2), a micro / nano bubble generating unit (5), and a control unit (9) are disposed on the floating platform (1); characterized in that, The micro-nano bubble generating unit (5) includes an inlet chamber (14), a Venturi contraction section (52), a throat (54), and a throttling expansion chamber (55) with progressively decreasing inner diameter, which are connected sequentially along the water flow direction. The inlet chamber (14) is connected to an air inlet pipe (51) extending above the water surface. An impeller (13) is rotatably installed in the inlet chamber (14). At least two sets of variable pitch spiral guide vanes (53) are connected in series along the axial direction in the Venturi contraction section (52). The pitch of the variable pitch spiral guide vanes (53) gradually decreases along the water flow direction. A throttling orifice plate (56) with progressively decreasing central throttling orifice diameter is provided between adjacent throttling expansion chambers (55). A bubble cutting unit (7) is provided at the outlet end of the diffusion section (57).

2. The solar-powered micro / nano aerator according to claim 1, characterized in that, A photocatalytic synergistic unit is provided at the outlet end of the diffusion section (57) of the micro-nano bubble generating unit (5). The photocatalytic synergistic unit includes a transparent flow guide (6) covering the outlet section of the diffusion section (57). The inner wall of the transparent flow guide (6) is coated with a TiO2 nanotube array photocatalytic coating (60). The photocatalytic synergistic unit also includes a light guide column (61) and a light-scattering prism (62). The upper end of the light guide column (61) is provided with a light-collecting part, which is located on the upper part of the floating platform (1). The lower end of the light guide column (61) extends into the top of the transparent flow guide (6) through the side wall opening at the top of the transparent flow guide (6) and connects to the light-scattering prism (62). The light-scattering prism (62) disperses the light to the bubble generating area inside the transparent flow guide (6).

3. The solar-powered micro / nano aerator according to claim 2, characterized in that, An annular flow guide gap is provided between the transparent flow guide hood (6) and the outer wall of the outlet end of the diffusion section (57) of the micro-nano bubble generating unit (5).

4. The solar-powered micro / nano aerator according to claim 1, characterized in that, A fully sealed drive unit is provided between the floating platform (1) and the micro-nano bubble generating unit (5).

5. The solar-powered micro / nano aerator according to claim 4, characterized in that, The fully sealed drive unit includes a sealed chamber (3), a submersible motor (30) located inside the sealed chamber (3), and a magnetic coupler (4) located at the bottom of the sealed chamber (3). The sealed chamber (3) is fixed below the floating platform (1) by a support column (11). The magnetic coupler (4) includes an active magnetic rotor (40), a driven magnetic rotor (41), and an isolation sleeve (42) fixed at the bottom opening of the sealed chamber (3). The active magnetic rotor (40) is driven to the output shaft of the submersible motor (30) and is located inside the isolation sleeve (42). The driven magnetic rotor (41) is rotatably mounted on the outside of the isolation sleeve (42) by an auxiliary bearing (45) and connected to the driven output shaft (44) by a torque adaptive buffer (43). The driven output shaft (44) is driven to the impeller (13) of the micro-nano bubble generating unit (5).

6. The solar-powered micro / nano aerator according to any one of claims 1-5, characterized in that, The bubble cutting unit (7) includes at least two layers of arc-shaped thin plates arranged at intervals along the flow direction, the spacing between each layer of arc-shaped thin plates decreasing along the flow direction, and the surface of the arc-shaped thin plates is coated with a superhydrophobic nano-coating (8).

7. The solar-powered micro / nano aerator according to any one of claims 1-5, characterized in that, The inner wall of the throttling expansion cavity (55) and / or the inner wall of the diffusion section (57) are coated with a superhydrophobic nanocoating (8).

8. The solar-powered micro / nano aerator according to any one of claims 1-5, characterized in that, The solar power unit (2) includes a dual-axis tracking mechanism (21) installed on the floating platform (1) and a photovoltaic panel (20) installed on the dual-axis tracking mechanism (21). The photovoltaic panel (20) is electrically connected to a battery pack (23) and a controller (22).

9. The solar-powered micro / nano aerator according to any one of claims 1-5, characterized in that, The inlet of the air inlet (51) above the water surface is equipped with a rain cap and a filter, and a one-way valve is provided on the air inlet (51); a filter screen is provided at the inlet (50) of the liquid inlet chamber (14).

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