A multi-stage coupled jet enhanced shear mixing aeration system and its application method

Abstract

The present invention discloses a multi-stage coupled jet-enhanced shear mixing aeration system and its application method. The aeration system includes an air inlet section, a liquid inlet section, a bubble generator connected to the common downstream of the air inlet section and the liquid inlet section, a regulating valve and an aeration tank connected in sequence to the downstream of the bubble generator; the bubble generator includes, from upstream to downstream, a gas-liquid mixing unit, a swirl shear unit, a turbulence enhancement unit, and an oscillation self-excitation unit; the present invention integrates negative pressure suction, eddy shear, and hydrodynamic cavitation effects into a device without moving parts; the gas-liquid mixture is broken into nano-scale bubbles in the terminal turbulent section; the present invention has the significant advantages of lower energy consumption, higher bubble nucleation rate, smaller particle size, and more uniform distribution. In addition, its unique multi-flow field coupling design makes it more adaptable to different water qualities and can maintain stable and efficient nano-bubble generation capabilities under a wider range of working conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of aeration systems, and in particular relates to a multi-stage coupled jet-enhanced shear mixing aeration system and an application method thereof. Background Art

[0002] Aeration, the process of forcibly dissolving gas in a liquid, is a core technology in water treatment, environmental remediation, and numerous other industrial fields. To address the inefficiency of traditional aeration technology, existing technologies have increasingly focused on reducing bubble size. Currently, micro- and nano-bubble generation technologies used in aeration applications both domestically and internationally include pressurized dissolved gas, the Venturi method, and electrolysis. The pressurized dissolved gas method generates a large number of microbubbles in water by first pressurizing the gas to dissolve it and then suddenly reducing the pressure. However, this method is energy-intensive, requires complex equipment, and requires a large footprint. The Venturi method, which draws in and ruptures gas through changes in fluid velocity and pressure within a convergent-convergent pipe, has a simple structure but low bubble generation efficiency, high water quality requirements, and is prone to clogging. While electrolysis can produce extremely small nanobubbles, its limited gas production, the high wear and tear of electrode materials, and the high processing costs limit its application in large-scale water treatment. Overall, existing technologies still lack the ability to control bubble size, maintain generator stability, and meet the demands of complex industrial applications. Summary of the Invention

[0003] The present invention provides a multi-stage coupled jet enhanced shear mixing aeration system and an application method thereof, which are used to solve technical problems such as efficient mixing, multi-stage enhanced shear, turbulent oscillation and multi-flow field coupling of micro-nano bubble generation.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A multi-stage coupled jet enhanced shear mixing aeration system comprises an air inlet section, a liquid inlet section, a bubble generator connected to the common downstream of the air inlet section and the liquid inlet section, a regulating valve and an aeration tank connected in sequence to the downstream of the bubble generator;

[0006] The bubble generator comprises a gas-liquid mixing unit, a swirl shear unit, a turbulence enhancement unit and an oscillation self-excitation unit in sequence from upstream to downstream;

[0007] The gas-liquid mixing unit comprises a liquid inlet section corresponding to the inflow of liquid, an air inlet section corresponding to the inflow of gas, a nozzle sequentially connected to the downstream of the liquid inlet section, a narrow channel provided on the upper and lower sides of the nozzle with the upper side located downstream of the air inlet section, an air suction chamber located downstream of the narrow channel, a gas-liquid mixing throat section and a gas-liquid mixing expansion section sequentially located downstream of the air suction chamber;

[0008] The swirl shear unit comprises a swirl shear convergence section connected to the downstream of the gas-liquid mixing expansion section, a spiral crushing section connected to the downstream of the swirl shear convergence section, a spiral guide column arranged inside the spiral crushing section, a front guide wall and a rear guide wall respectively arranged before and after the spiral guide column, and a spiral guide vane arranged on the spiral guide column;

[0009] The turbulence enhancement unit comprises a concave baffle disposed relative to the rear guide wall, a curved straight section located on the periphery of the spiral crushing section, a converging section disposed downstream of the curved straight section, a converging angle disposed at the intersection of the converging section, and a turbulence outlet section disposed downstream of the converging section;

[0010] The oscillation self-excitation unit includes an oscillation cavity correspondingly connected to the downstream of the turbulent outlet section, an oscillation central flow channel arranged at the center of the oscillation cavity, and an oscillation outlet arranged downstream of the oscillation central flow channel.

[0011] Furthermore, the total length of the gas-liquid mixing unit is 1.0 to 1.4 times the outer diameter of the turbulence enhancement unit; the diameter of the liquid inlet section is 1 / 3 to 2 / 3 of the outer diameter of the turbulence enhancement unit; the diameter of the gas inlet section is 1 / 2 to 2 / 3 of the diameter of the liquid inlet section;

[0012] The nozzle is arranged in an eight-shaped shape, with the large opening facing the liquid inlet section and the small opening facing the suction cavity; the convergence angle of the nozzle is 30-45 degrees;

[0013] The diameter of the narrow passage is 1 / 4 to 1 / 2 of the diameter of the air inlet section, and the narrow passage is arranged horizontally and is connected to the air suction cavity.

[0014] Furthermore, the suction cavity is in a tapered trumpet shape, the converging side of the suction cavity forms an angle of 60° with the horizontal, the length of the converging section of the suction cavity is 0.3 to 0.5 times the outer diameter of the turbulence enhancement unit; the outlet of the suction cavity is connected to the gas-liquid mixing throat section;

[0015] The diameter of the gas-liquid mixing throat section is 1 / 2 to 3 / 4 of the diameter of the liquid inlet section, and the length is 1.2 to 1.8 times the diameter of the liquid inlet section;

[0016] The expansion angle of the gas-liquid mixing expansion section is 30 to 55 degrees from the horizontal, and the length is 1.5 to 1.8 times the length of the convergent section of the suction cavity.

[0017] Furthermore, the contraction angle of the rotary shear convergence section is 30-45° to the horizontal, the width at the contraction port is 1 / 3-2 / 3 of the outer diameter of the turbulence enhancement unit, and the length of the rotary shear convergence section is 0.75-1.0 times the width at the contraction port.

[0018] Furthermore, the length of the spiral crushing section is 1.2 to 1.5 times the outer diameter of the turbulence enhancement unit, and a full-length spiral guide column is provided inside;

[0019] The spiral guide column is equipped with 8 to 12 spiral guide vanes at intervals. The inclination angle of the spiral guide vanes is 45° and the wall thickness is 2 to 5 mm.

[0020] The front guide wall and the rear guide wall are both configured as arc surfaces, and the diameter of the arc is 1 / 4 to 2 / 3 of the width of the contraction opening.

[0021] Furthermore, the length of the turbulence enhancement unit is 1.5 to 2 times the outer diameter of the turbulence enhancement unit;

[0022] The concave baffle is an arc-shaped surface with a diameter of 2 to 4 times the diameter of the spiral crushing section. The horizontal length between the center of the concave baffle and the center of the rear drainage wall is 1 / 5 to 1 / 3 times the diameter of the spiral crushing section.

[0023] The length of the curved straight section is 1 to 1.5 times the outer diameter of the turbulence enhancement unit, and the width of a single straight section is 0.2 to 0.4 times the outer diameter of the turbulence enhancement unit.

[0024] Furthermore, the convergence angle of the converging section is 60~75° to the horizontal, and the width is 0.1~0.3 times the outer diameter of the turbulence enhancement unit; the converging angle is an arc angle, and the arc diameter is 3 / 4~3 / 2 of the converging section width; the diameter of the turbulent outlet section is 0.4~0.7 times the diameter of the liquid inlet section.

[0025] Furthermore, the diameter of the oscillation center flow channel is set by the diameter of the turbulence outlet section, and the length is 1.0 to 1.2 times the outer diameter of the turbulence enhancement unit; the oscillation outlet diameter is the oscillation center flow channel;

[0026] The oscillation cavity is a trapezoidal cavity with a length ratio of the long bottom to the short bottom between 1 and 3, the bottom length is 0.8 to 1.2 times the diameter of the oscillation center flow channel, the oscillation cavity height is 3 to 5 times the diameter of the oscillation center flow channel, the front wall of the oscillation cavity is vertical, and the rear wall is at an angle of 60° to the horizontal.

[0027] Furthermore, the air inlet section and the bubble generator are connected via a pipeline, and a gas flow meter is connected to the pipeline;

[0028] The liquid inlet section is connected to the bubble generator through a pipeline, and a pressure gauge is connected to the pipeline; the inlet end of the liquid inlet section is connected to an external liquid supply source or to the water outlet at the bottom of the aeration tank.

[0029] Furthermore, the application method of the multi-stage coupled jet enhanced shear mixing aeration system has the following specific steps:

[0030] Step 1: Connect the gas supply source and liquid supply source through the gas inlet section and liquid inlet section respectively to introduce gas and liquid; the gas passes through the gas flow meter, and the liquid passes through the water pump and pressure gauge; the gas and liquid merge in the bubble generator;

[0031] Step 2: The liquid enters the nozzle through the liquid inlet section to form a jet, thereby generating negative pressure in the suction chamber; the gas enters through the air inlet section and then accelerates in the narrow channel, passing through the suction chamber and mixing with the liquid in the jet to form a gas-liquid mixed flow;

[0032] The velocity of the gas-liquid mixed flow reaches its maximum at the gas-liquid mixing throat section, while the static pressure drops significantly, forming a local negative pressure zone. The pressure in this negative pressure zone is lower than the external atmospheric pressure or the set gas supply pressure, actively drawing gas into the high-speed liquid flow through the gas inlet. At this stage, the gas-liquid two-phase flow is mixed under the action of the turbulent vortex at the outlet of the gas-liquid mixing throat section, and the gas is initially dispersed into larger bubbles.

[0033] The vortex is a very powerful force that is used to pull the liquid out of the air and into the vortex, and then the liquid is pulled out of the vortex, and the air is pulled out of the vortex, and the vortex ...

[0034] Step 4: After the gas-liquid mixed flow flows out of the spiral crushing section, it first hits the concave baffle, flows along the inner wall of the baffle and is rapidly divided, and then passes through the curved straight section and then merges at the converging section. When the high-speed gas-liquid mixed flow travels in the long straight channel with continuous bends, its flow direction is forced to undergo multiple sharp changes. The curved path induces violent turbulence, strong secondary flow and a continuously fluctuating pressure field in the fluid. The strong shear force and centrifugal force exerted on the fluid at each corner acts like continuous mechanical kneading, effectively pre-treating the formed micron-sized bubbles, further refining and homogenizing them.

[0035] Step 5. The gas-liquid mixed flow efficiently merges at the confluence angle at the turbulent outlet and is then injected into the oscillation cavity. The inherent acoustic resonance frequency of the oscillation cavity matches the vortex shedding frequency or pressure pulsation frequency generated by the upstream fluid. When the two frequencies are coupled, the kinetic energy of the fluid itself will stimulate the cavity to produce strong acoustic resonance, forming a stable, high-intensity standing wave energy field in the cavity. The microbubbles entering this energy field will be subjected to the rapidly alternating positive and negative sound pressures, and will be forced to undergo high-frequency violent contraction and expansion. This high-intensity acoustic oscillation can effectively overcome the surface tension of the bubbles, and through surface instability or local inertial cavitation effects, the micron-sized bubbles are efficiently broken and atomized into smaller nano-sized bubbles, ultimately completing an efficient nano-scaling process. The gas-liquid mixed flow flows out through the oscillation center flow channel and the oscillation outlet. The outflowing gas-liquid mixed flow passes through the pipeline and is aerated in the aeration tank by controlling the flow rate through the regulating valve.

[0036] The beneficial effects of the present invention are embodied in:

[0037] 1) The present invention uses a gas-liquid mixing unit to create a negative pressure zone, which facilitates efficient mixing of gas and liquid and accelerates the gas-liquid mixed flow. The swirl shear unit forms a vortex in the spiral crushing section of the gas-liquid mixed flow, and the rotating vortex performs multi-stage shearing to tear the bubbles into smaller sizes. The turbulence enhancement unit then forms turbulence, and after multiple bends and final confluence of the flow channel, it facilitates further refinement and homogenization of the bubble size. The oscillation self-excitation unit is provided, and the high-frequency violent contraction and expansion can effectively tear the bubble size into nanometer size.

[0038] 2) The present invention integrates negative pressure suction, vortex shearing, and hydrodynamic cavitation effects into a device without moving parts. During operation, the high-speed liquid flow first utilizes self-absorption of gas. Then, within the static vortex device, the powerful shear force tears large bubbles into micron-sized bubbles. Finally, the gas-liquid mixture is broken into nanometer-sized bubbles in the terminal turbulent section.

[0039] 3) Compared with existing technologies, the present invention has the significant advantages of lower energy consumption, higher bubble nucleation rate, smaller particle size and more uniform distribution. In addition, its unique multi-flow field coupling design makes it more adaptable to different water qualities and can maintain stable and efficient nanobubble generation under a wider range of operating conditions.

[0040] 4) The present invention is highly efficient and energy-efficient, with low operating costs: Through the synergistic enhancement of multiple physical fields, the energy exchange and utilization efficiency of the gas-liquid two-phase system is greatly improved. High-concentration nanobubbles can be generated at relatively low input power, significantly reducing the long-term operating energy consumption and cost of the equipment.

[0041] 5) The unique cyclonic shearing and fragmentation mechanism of this invention ensures that the bubbles experience sufficient, intense, and uniform forces during their formation. This results in an extremely small average particle size of the resulting nanobubbles (ultrafine bubbles with diameters of 100-500nm can be generated), and a very narrow size distribution range, avoiding the mixing of large and small bubbles common in traditional technologies and improving the uniformity of bubble function.

[0042] 6) The equipment of the present invention has a compact structure and high reliability: the design optimizes the internal flow channel to achieve efficient functional integration in a compact space; it relies on the hydraulic properties of the fluid itself to work, has fewer wear parts, a low failure rate, and has higher stability and a longer service life;

[0043] 7) The present invention has strong adaptability to working conditions and a wide range of applications: the multi-flow field coupling design ensures that stable bubble generation efficiency and effect can be maintained even in complex or changing liquid environments, making it suitable for a variety of complex application scenarios such as sewage treatment, modern agriculture, and mineral flotation.

[0044] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or may be understood by practicing the present invention; the main purpose and other advantages of the present invention can be realized and obtained through the solutions particularly pointed out in the description. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a schematic diagram of the connection of the multi-stage coupled jet enhanced shear mixing aeration system Figure 1 ;

[0046] Figure 2 This is a schematic diagram of the connection of the multi-stage coupled jet enhanced shear mixing aeration system Figure 2 ;

[0047] Figure 3 is a three-dimensional schematic diagram of a bubble generator;

[0048] Figure 4 This is a cross-sectional diagram of a bubble generator. Figure 1 ;

[0049] Figure 5 This is a cross-sectional diagram of a bubble generator. Figure 2 ;

[0050] Figure 6 It is a schematic diagram of the structure of the gas-liquid mixing unit;

[0051] Figure 7 is a schematic diagram of the swirl shear unit structure;

[0052] Figure 8 It is a schematic diagram of the turbulence enhancement unit structure;

[0053] Figure 9 It is a schematic diagram of the structure of the oscillating self-excited unit;

[0054] Figure 10 This is a simulation diagram of multi-stage coupled jet-enhanced shear mixing in a bubble generator;

[0055] Figure 11 This is a schematic diagram of the relationship between bubble particle size and concentration.

[0056] Figure markings: 1-air inlet section, 2-liquid inlet section, 3-gas flow meter, 4-water pump, 5-pressure gauge, 6-bubble generator, A-gas-liquid mixing unit, A1-liquid inlet section, A2-air inlet section, A3-nozzle, A4-narrow channel, A5-intake chamber, A6-gas-liquid mixing throat section, A7-gas-liquid mixing expansion section, B-swirl shear unit, B1-swirl shear convergence section, B2-spiral crushing section, B3-spiral guide column, B4-front guide wall, B5-rear guide wall, B6-spiral guide vane, C-turbulence enhancement unit, C1-concave baffle, C2-bending straight section, C3-convergence section, C4-convergence angle, C5-turbulence outlet section, D-oscillation self-excitation unit, D1-oscillation chamber, D2-oscillation central flow channel, D3-oscillation outlet, 7-pipeline, 8-regulating valve, 9-aeration tank. DETAILED DESCRIPTION

[0057] like Figures 1 to 9 As shown, a multi-stage coupled jet enhanced shear mixing aeration system includes an air inlet section 1, a liquid inlet section 2, a bubble generator 6 connected to the common downstream of the air inlet section 1 and the liquid inlet section 2, a regulating valve 8 and an aeration tank 9 connected in sequence to the downstream of the bubble generator 6.

[0058] In this embodiment, the working flow rate of the bubble generator 6 of this system depends on the water pump 4 it is paired with, and can cover a wide range from several liters / hour to hundreds of cubic meters / hour. To ensure the foaming effect and system pressure safety, the gauge pressure reading of the bubble generator 6 pressure gauge is generally maintained between 0.2 and 0.5 MPa. The gas-liquid ratio suitable for the mixed aeration system is usually 2% to 9%. If the gas-liquid ratio is too low, it will result in a low gas content and a small number of bubbles; if the gas-liquid ratio is too high, although the gas content is high, the bubble particle size will be too large. The operating temperature and acid and alkali resistance depend on the manufacturing material of the generator, which is generally aluminum alloy or stainless steel. Conventional products are suitable for environments with an operating temperature of 5 to 60°C and a pH value of 4 to 10.

[0059] In this embodiment, the air supply source for air inlet section 1 can be selected from various gases, such as air, oxygen, and carbon dioxide, depending on the application scenario. It is generally recommended to deploy a filter assembly at the air inlet end to remove particulate matter and impurities to prevent damage to the equipment. The water supply source for liquid inlet section 2 can be selected from tap water, river, lake, or reservoir water, reactor water, or other mobile liquid phases, depending on the application scenario. This liquid must be a Newtonian liquid, and the particle size of any suspended particulate matter must not exceed 3 mm.

[0060] In this embodiment, the air inlet section 1 is connected to the bubble generator 6 via a pipe 7, to which a gas flowmeter 3 is connected. The selection of the gas flowmeter 3 should be based on actual flow requirements, and its operating flow rate should be set between 1 / 4 and 3 / 4 of the meter's range. The liquid inlet section 2 is connected to the bubble generator 6 via a pipe 7, to which a pressure gauge 5 is connected. The inlet end of the liquid inlet section 2 is connected to an external liquid supply source or to the bottom outlet of the aeration tank 9.

[0061] In this embodiment, the bubble generator 6 includes a gas-liquid mixing unit A, a swirl shearing unit B, a turbulence enhancement unit C and an oscillation self-excitation unit D in sequence from upstream to downstream.

[0062] In this embodiment, the gas-liquid mixing unit A includes a liquid inlet section A1 corresponding to the inflow of liquid, an air inlet section A2 corresponding to the inflow of gas, a nozzle A3 connected to the downstream of the liquid inlet section A1, a narrow channel A4 arranged on the upper and lower sides of the nozzle A3 and the upper side is located downstream of the air inlet section A2, an air suction chamber A5 located downstream of the narrow channel A4, a gas-liquid mixing throat section A6 and a gas-liquid mixing expansion section A7 located downstream of the air suction chamber A5 in sequence.

[0063] In this embodiment, the total length of the gas-liquid mixing unit A is 1.0 to 1.4 times the outer diameter of the turbulence enhancement unit C; the diameter of the liquid inlet section A1 is 1 / 3 to 2 / 3 of the outer diameter of the turbulence enhancement unit C; the diameter of the air inlet section A2 is 1 / 2 to 2 / 3 of the diameter of the liquid inlet section A1; the nozzle A3 is arranged in an eight-shaped shape, with the large opening facing the liquid inlet section A1 and the small opening facing the suction chamber A5; the convergence angle of the nozzle A3 is 30 to 45°; the diameter of the narrow channel A4 is 1 / 4 to 1 / 2 of the diameter of the air inlet section A2, and the narrow channel A4 is arranged horizontally and is connected to the suction chamber A5.

[0064] In this embodiment, the air suction chamber A5 is in the shape of a tapered trumpet, the convergent side of the air suction chamber A5 forms an angle of 60° with the horizontal, and the length of the convergent section of the air suction chamber A5 is 0.3 to 0.5 times the outer diameter of the turbulence enhancement unit C; the outlet of the air suction chamber A5 is connected through the gas-liquid mixing throat section A6; the diameter of the gas-liquid mixing throat section A6 is 1 / 2 to 3 / 4 of the diameter of the liquid inlet section A1, and the length is 1.2 to 1.8 times the diameter of the liquid inlet section A1; the expansion angle of the gas-liquid mixing expansion section A7 is 30 to 55° with the horizontal, and the length is 1.5 to 1.8 times the length of the convergent section of the air suction chamber A5.

[0065] In this embodiment, the swirl shear unit B includes a rotary shear convergence section B1 correspondingly connected to the downstream of the gas-liquid mixing expansion section A7, a spiral crushing section B2 connected to the downstream of the rotary shear convergence section B1, a spiral guide column B3 arranged inside the spiral crushing section B2, a front guide wall B4 and a rear guide wall B5 respectively arranged in front and behind the spiral guide column B3, and a spiral guide vane B6 arranged on the spiral guide column B3.

[0066] In this embodiment, the shear convergence section B1 has a contraction angle of 30-45° relative to the horizontal, and its width at the contraction is 1 / 3-2 / 3 the outer diameter of the turbulence enhancement unit C. The length of the shear convergence section B1 is 0.75-1.0 times the width at the contraction. The spiral crushing section B2 is 1.2-1.5 times the outer diameter of the turbulence enhancement unit C and contains a full-length spiral guide column B3. The spiral guide column B3 is interspersed with 8-12 spiral guide vanes B6 at intervals, each with a 45° inclination angle and a wall thickness of 2-5 mm. Both the front and rear guide walls B4 and B5 are arc-shaped, with a diameter of 1 / 4-2 / 3 the width at the contraction.

[0067] In this embodiment, the turbulence enhancement unit C includes a concave baffle C1 arranged relative to the rear guide wall B5, a curved straight section C2 located on the outer periphery of the spiral crushing section B2, a converging section C3 arranged downstream of the curved straight section C2, a converging angle C4 arranged at the intersection of the converging section C3, and a turbulent outlet section C5 arranged downstream of the converging section C3.

[0068] In this embodiment, the length of the turbulence enhancement unit C is 1.5 to 2 times its outer diameter. The concave baffle C1 is an arc-shaped surface with a diameter 2 to 4 times the diameter of the spiral crushing section B2. The horizontal length between the center of the concave baffle C1 and the center of the rear drainage wall B5 is 1 / 5 to 1 / 3 the diameter of the spiral crushing section B2. The length of the curved straight section C2 is 1 to 1.5 times the outer diameter of the turbulence enhancement unit C, and the width of a single straight section is 0.2 to 0.4 times the outer diameter of the turbulence enhancement unit C. The converging section C3 has a convergence angle of 60 to 75 degrees from the horizontal and a width of 0.1 to 0.3 times the outer diameter of the turbulence enhancement unit C. The converging angle C4 is an arc angle with a diameter of 3 / 4 to 3 / 2 the width of the converging section C3. The diameter of the turbulence outlet section C5 is 0.4 to 0.7 times the diameter of the liquid inlet section A1.

[0069] In this embodiment, the oscillation self-excitation unit D includes an oscillation cavity D1 correspondingly connected to the downstream of the turbulent outlet section C5, an oscillation central flow channel D2 arranged at the center of the oscillation cavity D1, and an oscillation outlet D3 arranged downstream of the oscillation central flow channel D2.

[0070] In this embodiment, the diameter of the oscillation center flow channel D2 corresponds to the diameter of the turbulence outlet section C5, and the length is 1.0~1.2 times the outer diameter of the turbulence enhancement unit C; the diameter of the oscillation outlet D3 is the oscillation center flow channel D2; the oscillation cavity D1 is a trapezoidal cavity, the length ratio of its long bottom to its short bottom is between 1~3, the bottom length is 0.8~1.2 of the diameter of the oscillation center flow channel D2, the height of the oscillation cavity D1 is 3~5 times the diameter of the oscillation center flow channel D2, the front wall of the oscillation cavity D1 is vertical, and the rear wall is at an angle of 60° to the horizontal.

[0071] Combine Figures 1 to 11 As shown in FIG, the application method of the multi-stage coupled jet enhanced shear mixing aeration system is as follows:

[0072] Step 1: Connect the air supply source and liquid supply source through the air inlet section 1 and the liquid inlet section 2 respectively to introduce gas and liquid; the gas passes through the gas flow meter 3, and the liquid passes through the water pump 4 and the pressure gauge 5; the gas and liquid converge in the bubble generator 6.

[0073] Step 2: The liquid enters the nozzle A3 through the liquid inlet section A1 to form a jet, thereby generating negative pressure in the suction chamber A5; the gas enters through the air inlet section A2 and then accelerates at the narrow channel A4, passing through the suction chamber A5 to mix with the liquid in the jet to form a gas-liquid mixed flow.

[0074] The velocity of the gas-liquid mixed flow reaches its maximum at the gas-liquid mixing throat section A6, while the static pressure drops significantly, forming a local negative pressure zone; the pressure of this negative pressure zone is lower than the external atmospheric pressure or the set gas supply pressure, so that the gas is actively sucked into the high-speed liquid flow through the gas inlet; at this stage, the gas-liquid two-phase flow is mixed under the action of the turbulent vortex at the outlet of the gas-liquid mixing throat section A6, and the gas is initially dispersed into larger bubbles.

[0075] Step 3: When the gas-liquid mixed flow passes through the gas-liquid mixing expansion section A7, the flow channel gradually widens, the liquid flow rate decreases, and a velocity gradient is generated to further disperse the bubbles, and then it is continuously accelerated through the spiral shear convergence section B1; enters the spiral crushing section B2, and passes through the spiral guide vane B6 of the spiral guide column B3 in the spiral crushing section B2; in the spiral crushing section B2, the gas-liquid mixed flow produces a violent, high angular velocity rotational motion, forming a strong vortex; in this high-speed rotating flow field, a huge velocity gradient is generated inside the fluid, thereby exerting a strong shear force on the bubbles; this shear force can effectively overcome the surface tension of the bubbles, and continuously tear and break the large bubbles formed by the mixture into smaller microbubbles; at the same time, the centrifugal force of the vortex will cause the bubbles with lower density to tend to gather in the low-pressure area at the center of the vortex, further enhancing the interaction and mass transfer efficiency between the gas and liquid phases; among them, the setting of the front guide wall B4 and the rear guide wall B5 quickly diverts the gas-liquid mixed flow to prevent the bubbles from staying here and thus merging.

[0076] Step 4: After the gas-liquid mixed flow flows out of the spiral crushing section B2, it will first hit the concave baffle C1, flow along the inner wall of the baffle and be rapidly diverted, and then pass through the curved straight section C2 and then merge through the merging section C3; when the high-speed gas-liquid mixed flow travels in the long straight channel with continuous bends, its flow direction is forced to undergo multiple sharp changes; the curved path induces violent turbulence, strong secondary flow and continuously fluctuating pressure field in the fluid; the strong shear force and centrifugal force exerted on the fluid at each corner is like continuous mechanical kneading, which effectively pre-treats the formed micron-sized bubbles, further refines and homogenizes them.

[0077] Step 5: The gas-liquid mixed flow efficiently merges at the confluence angle C4 at the turbulent outlet and is then injected into the oscillation cavity D1. The inherent acoustic resonance frequency of the oscillation cavity D1 matches the vortex shedding frequency or pressure pulsation frequency generated by the upstream fluid. When the two frequencies are coupled, the kinetic energy of the fluid itself will stimulate the cavity to produce strong acoustic resonance, forming a stable, high-intensity standing wave energy field in the cavity. Microbubbles entering this energy field will be subjected to the rapidly alternating positive and negative sound pressures, forcing them to undergo high-frequency and violent contraction and expansion. This high-intensity acoustic oscillation can effectively overcome the surface tension of the bubbles, and through surface instability or local inertial cavitation effects, the micron-sized bubbles are efficiently broken and atomized into smaller nano-sized bubbles, ultimately completing an efficient nano-scaling process. The gas-liquid mixed flow flows out through the oscillation center flow channel D2 and the oscillation outlet D3. The outflowing gas-liquid mixed flow passes through the pipeline 7 and is aerated in the aeration tank 9 by the corresponding control flow rate through the regulating valve 8.

[0078] In this embodiment, a certain brand of centrifugal pump is used to drive a 1.5m 3 / h of water flow, so that it flows through the stainless steel bubble generator 6. Under the condition of setting the gas-liquid ratio to 4%, the water sample was collected after the system was run for 15 minutes. The bubble size and concentration of the sample were tested using a nanoparticle tracking analyzer, such as Figure 11 As shown in the figure, the median diameter of the bubbles was measured to be 102.7 nm, and the total number of bubbles was 2.4×10 8 More than 1000 ml / mL.

[0079] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that a person skilled in the art can conceive within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention.

Claims

1. A multi-stage coupled jet enhanced shear mixing aeration system, characterized in that: It comprises an air inlet section, a liquid inlet section, a bubble generator connected to the common downstream of the air inlet section and the liquid inlet section, a regulating valve and an aeration tank connected in sequence to the downstream of the bubble generator; The bubble generator comprises a gas-liquid mixing unit, a swirl shear unit, a turbulence enhancement unit and an oscillation self-excitation unit in sequence from upstream to downstream; The gas-liquid mixing unit comprises a liquid inlet section corresponding to the inflow of liquid, an air inlet section corresponding to the inflow of gas, a nozzle sequentially connected to the downstream of the liquid inlet section, a narrow channel provided on the upper and lower sides of the nozzle with the upper side located downstream of the air inlet section, an air suction chamber located downstream of the narrow channel, a gas-liquid mixing throat section and a gas-liquid mixing expansion section sequentially located downstream of the air suction chamber; The swirl shear unit comprises a swirl shear convergence section connected to the downstream of the gas-liquid mixing expansion section, a spiral crushing section connected to the downstream of the swirl shear convergence section, a spiral guide column arranged inside the spiral crushing section, a front guide wall and a rear guide wall respectively arranged before and after the spiral guide column, and a spiral guide vane arranged on the spiral guide column; The turbulence enhancement unit comprises a concave baffle disposed relative to the rear guide wall, a curved straight section located on the periphery of the spiral crushing section, a converging section disposed downstream of the curved straight section, a converging angle disposed at the intersection of the converging section, and a turbulence outlet section disposed downstream of the converging section; The oscillation self-excitation unit includes an oscillation cavity correspondingly connected to the downstream of the turbulent outlet section, an oscillation central flow channel arranged at the center of the oscillation cavity, and an oscillation outlet arranged downstream of the oscillation central flow channel.

2. A multi-stage coupled jet enhanced shear mixing aeration system according to claim 1, characterized in that: The total length of the gas-liquid mixing unit is 1.0 to 1.4 times the outer diameter of the turbulence enhancement unit; the diameter of the liquid inlet section is 1 / 3 to 2 / 3 of the outer diameter of the turbulence enhancement unit; the diameter of the gas inlet section is 1 / 2 to 2 / 3 of the diameter of the liquid inlet section; The nozzle is arranged in an eight-shaped shape, with the large opening facing the liquid inlet section and the small opening facing the suction cavity; the convergence angle of the nozzle is 30-45 degrees; The diameter of the narrow passage is 1 / 4 to 1 / 2 of the diameter of the air inlet section, and the narrow passage is arranged horizontally and is connected to the air suction cavity.

3. A multi-stage coupled jet enhanced shear mixing aeration system according to claim 2, characterized in that: The suction cavity is in a tapered trumpet shape, with the converging side of the suction cavity forming an angle of 60° with the horizontal. The length of the converging section of the suction cavity is 0.3 to 0.5 times the outer diameter of the turbulence enhancement unit. The outlet of the suction cavity is connected to the gas-liquid mixing throat section. The diameter of the gas-liquid mixing throat section is 1 / 2 to 3 / 4 of the diameter of the liquid inlet section, and the length is 1.2 to 1.8 times the diameter of the liquid inlet section; The expansion angle of the gas-liquid mixing expansion section is 30 to 55 degrees from the horizontal, and the length is 1.5 to 1.8 times the length of the convergent section of the suction cavity.

4. A multi-stage coupled jet enhanced shear mixing aeration system according to claim 3, characterized in that: The contraction angle of the rotary shear convergence section is 30-45 degrees to the horizontal, the width at the contraction port is 1 / 3-2 / 3 of the outer diameter of the turbulence enhancement unit, and the length of the rotary shear convergence section is 0.75-1.0 times the width at the contraction port.

5. The multi-stage coupled jet enhanced shear mixing aeration system according to claim 4, characterized in that: The length of the spiral crushing section is 1.2 to 1.5 times the outer diameter of the turbulence enhancement unit, and a full-length spiral guide column is provided inside. The spiral guide column is equipped with 8 to 12 spiral guide vanes at intervals. The inclination angle of the spiral guide vanes is 45° and the wall thickness is 2 to 5 mm. The front guide wall and the rear guide wall are both configured as arc surfaces, and the diameter of the arc is 1 / 4 to 2 / 3 of the width of the contraction opening.

6. The multi-stage coupled jet enhanced shear mixing aeration system according to claim 5, characterized in that: The length of the turbulence enhancement unit is 1.5 to 2 times the outer diameter of the turbulence enhancement unit; The concave baffle is an arc-shaped surface with a diameter of 2 to 4 times the diameter of the spiral crushing section. The horizontal length between the center of the concave baffle and the center of the rear drainage wall is 1 / 5 to 1 / 3 times the diameter of the spiral crushing section. The length of the curved straight section is 1 to 1.5 times the outer diameter of the turbulence enhancement unit, and the width of a single straight section is 0.2 to 0.4 times the outer diameter of the turbulence enhancement unit.

7. The multi-stage coupled jet enhanced shear mixing aeration system according to claim 6, characterized in that: The convergence angle of the confluence section is 60~75° to the horizontal, and the width is 0.1~0.3 times the outer diameter of the turbulence enhancement unit; the confluence angle is an arc angle, and the arc diameter is 3 / 4~3 / 2 of the confluence section width; the diameter of the turbulence outlet section is 0.4~0.7 times the diameter of the liquid inlet section.

8. The multi-stage coupled jet enhanced shear mixing aeration system according to claim 7, characterized in that: The diameter of the oscillation center flow channel corresponds to the diameter of the turbulence outlet section, and its length is 1.0~1.2 times the outer diameter of the turbulence enhancement unit; the oscillation outlet diameter is the oscillation center flow channel; The oscillation cavity is a trapezoidal cavity with a length ratio of the long bottom to the short bottom between 1 and 3, the bottom length is 0.8 to 1.2 times the diameter of the oscillation center flow channel, the oscillation cavity height is 3 to 5 times the diameter of the oscillation center flow channel, the front wall of the oscillation cavity is vertical, and the rear wall is at an angle of 60° to the horizontal.

9. The multi-stage coupled jet enhanced shear mixing aeration system according to claim 8, characterized in that: The air inlet section and the bubble generator are connected via a pipeline, and a gas flow meter is connected to the pipeline; The liquid inlet section is connected to the bubble generator through a pipeline, and a pressure gauge is connected to the pipeline; the inlet end of the liquid inlet section is connected to an external liquid supply source or to the water outlet at the bottom of the aeration tank.

10. An application method of the multi-stage coupled jet enhanced shear mixing aeration system according to claim 9, characterized in that: The specific steps are as follows: Step 1: Connect the gas supply source and liquid supply source through the gas inlet section and liquid inlet section respectively to introduce gas and liquid; the gas passes through the gas flow meter, and the liquid passes through the water pump and pressure gauge; the gas and liquid merge in the bubble generator; Step 2: The liquid enters the nozzle through the liquid inlet section to form a jet, thereby generating negative pressure in the suction cavity; The gas enters through the air inlet section and then accelerates at the narrow channel. It passes through the suction chamber and mixes with the jet liquid to form a gas-liquid mixed flow. The velocity of the gas-liquid mixed flow reaches its maximum at the gas-liquid mixing throat section, while the static pressure drops significantly, forming a local negative pressure zone. The pressure in this negative pressure zone is lower than the external atmospheric pressure or the set gas supply pressure, actively drawing gas into the high-speed liquid flow through the gas inlet. At this stage, the gas-liquid two-phase flow is mixed under the action of the turbulent vortex at the outlet of the gas-liquid mixing throat section, and the gas is initially dispersed into larger bubbles. The vortex is a very powerful force that is used to pull the liquid out of the air and into the vortex, and then the liquid is pulled out of the vortex, and the air is pulled out of the vortex, and the vortex ... Step 4: After the gas-liquid mixed flow flows out of the spiral crushing section, it first hits the concave baffle, flows along the inner wall of the baffle and is rapidly divided, and then passes through the curved straight section and then merges at the converging section. When the high-speed gas-liquid mixed flow travels in the long straight channel with continuous bends, its flow direction is forced to undergo multiple sharp changes. The curved path induces violent turbulence, strong secondary flow and a continuously fluctuating pressure field in the fluid. The strong shear force and centrifugal force exerted on the fluid at each corner acts like continuous mechanical kneading, effectively pre-treating the formed micron-sized bubbles, further refining and homogenizing them. Step 5. The gas-liquid mixed flow efficiently merges at the confluence angle at the turbulent outlet and is then injected into the oscillation cavity. The inherent acoustic resonance frequency of the oscillation cavity matches the vortex shedding frequency or pressure pulsation frequency generated by the upstream fluid. When the two frequencies are coupled, the kinetic energy of the fluid itself will stimulate the cavity to produce strong acoustic resonance, forming a stable, high-intensity standing wave energy field in the cavity. The microbubbles entering this energy field will be subjected to the rapidly alternating positive and negative sound pressures, and will be forced to undergo high-frequency violent contraction and expansion. This high-intensity acoustic oscillation can effectively overcome the surface tension of the bubbles, and through surface instability or local inertial cavitation effects, the micron-sized bubbles are efficiently broken and atomized into smaller nano-sized bubbles, ultimately completing an efficient nano-scaling process. The gas-liquid mixed flow flows out through the oscillation center flow channel and the oscillation outlet. The outflowing gas-liquid mixed flow passes through the pipeline and is aerated in the aeration tank by controlling the flow rate through the regulating valve.

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