Aeration generation system containing a self-excited oscillation turbulent shear device and its application method

Abstract

The present invention discloses an aeration generation system containing a self-excited oscillation turbulent shear device and an application method thereof. The aeration generation system includes a self-excited oscillation turbulent shear device, a water inlet unit and an air inlet unit connected upstream of the self-excited oscillation turbulent shear device, and an aeration tank connected downstream of the self-excited oscillation turbulent shear device. Through the coordinated regulation of the microchannel geometric parameters and fluid dynamics, the present invention realizes the precise control of the bubble size and distribution, and the particle size is relatively concentrated, avoiding the particle size dispersion caused by random fragmentation or insufficient turbulent shear in the traditional method. Only a low-pressure pump is required to drive the fluid, without high-pressure vessels, high-power ultrasound or electrode components, greatly reducing the energy consumption, and there is no risk of electrode passivation or membrane pollution, and it is suitable for fluids containing particulate matter or high turbidity. The proposed self-excited oscillation turbulent shear device has no microchannels and is also different from the existing nanobubble generators that must be equipped with release devices, and is not easy to block.

Description

Technical Field

[0001] The present invention relates to the technical field of aeration systems, and particularly to an aeration generation system containing a self-excited oscillation turbulent shear device and an application method thereof. Background Art

[0002] As the core means of efficient gas-liquid mass transfer reaction, the microporous aeration technology disperses pressurized gas into fine bubbles through the tiny pore structures immersed in the liquid phase (such as ceramic microporous disks, rubber diaphragms, sintered metal microporous disks, perforated steel pipes, etc.). The mainstream nano-bubble generation technologies mainly include the pressurized dissolution degassing method, the hydrodynamic cavitation method, the ultrasonic cavitation method, the membrane dispersion method, and the electrochemical gas evolution method. The above methods generally face bottlenecks such as high equipment complexity, high operating costs, weak anti-pollution ability, or insufficient large-scale production capacity. For example, the high energy consumption of the pressurization method and the ultrasonic method significantly increases the operating cost, and the material loss problems of the hydrodynamic cavitation method and the electrochemical method exacerbate the maintenance burden, while the membrane dispersion method has an increased downtime frequency due to the risk of membrane blockage, further restricting its applicability in industrial scenarios. Therefore, developing a nano-bubble generator with low energy consumption, high throughput, strong anti-pollution ability, and adaptable to complex working conditions has become the core challenge to break through the industrial application barriers.

[0003] Aiming at the problems existing in the existing nano-bubble generation technologies, such as complex equipment, high energy consumption, poor anti-pollution ability, limited fragmentation degree, and insufficient large-scale production capacity, the present invention proposes a nano-bubble generation device based on the self-excited oscillation turbulent shear method, which efficiently breaks gas into nano-scale bubbles through its own oscillation mixing and the high shear force and two-phase interface instability effect in the microfluidic channel. Summary of the Invention

[0004] The present invention provides an aeration generation system containing a self-excited oscillation turbulent shear device and an application method thereof, which are used to solve technical problems such as oscillation mixing during bubble generation, high shear force in the microfluidic channel, and instability of the two-phase interface.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] An aeration generation system containing a self-excited oscillation turbulent shear device includes a self-excited oscillation turbulent shear device, a water inlet unit and an air inlet unit connected upstream of the self-excited oscillation turbulent shear device, and an aeration tank connected downstream of the self-excited oscillation turbulent shear device;

[0007] The self-excited oscillation turbulent shear device includes an inlet section, a self-excited oscillation cavity section connected in series downstream of the inlet section, a turbulent shear cavity section connected in series downstream of the self-excited oscillation cavity section, a gradually expanding section connected in series below the turbulent shear cavity section, a bent channel section connected in series downstream of the gradually expanding section, an expansion cavity section connected in series downstream of the bent channel section, and a diversion outlet section connected in series downstream of the expansion cavity section;

[0008] The turbulent shear cavity section includes a turbulent shear cavity wall and turbulent shear blocks disposed inside the shear cavity wall, and the turbulent shear blocks are spaced apart to form a gradually expanding channel;

[0009] The bent channel section includes a bent channel pipe and baffle plates disposed inside the bent channel pipe; the baffle plates are alternately spaced on both sides and form a multi-stage S-shaped channel.

[0010] Further, the water inlet unit is connected by a water inlet pipe and a venturi tube; the air inlet unit is connected to a flow meter downstream of an air inlet pipe and then to the venturi tube of the water inlet unit, and the downstream of the venturi tube is connected to a centrifugal pump, and then is connected to a self-excited oscillation turbulent shear device through a pipeline.

[0011] Further, the water inlet pipe is connected to a water supply source, and the downstream of the self-excited oscillation turbulent shear device is connected to a regulating valve and is connected to the bottom of an aeration tank through a pipeline;

[0012] Or the water inlet pipe is connected to the bottom of the aeration tank, and the downstream of the self-excited oscillation turbulent shear device is connected to a regulating valve and is connected to the upper middle part of the aeration tank through a pipeline.

[0013] Further, the inlet section includes an inlet incoming flow section and an inlet outgoing flow section, and the inlet incoming flow section is connected to a centrifugal pump;

[0014] Both the inlet incoming flow section and the inlet outgoing flow section are linearly arranged, and the length of the inlet incoming flow section is 3 to 4 times its diameter or width; the diameter or width of the inlet outgoing flow section corresponds to that of the inlet incoming flow section.

[0015] Further, the inlet section includes an inlet incoming flow section, an inlet contraction pipe connected in sequence to the inlet incoming flow section, and an inlet outgoing flow section connected in sequence to the inlet contraction pipe;

[0016] Air guiding sections are arranged on both sides of the inlet contraction pipe, and the air guiding sections are directly connected to an air supply source;

[0017] Both the inlet incoming flow section, the inlet contraction pipe and the inlet outgoing flow section are linearly arranged;

[0018] The contraction angle of the inlet contraction pipe forms an angle of 25 - 40 degrees with the horizontal, the diameter or width of the contraction pipe section is 1 / 2 to 3 / 4 of the diameter of the inlet incoming flow section, and the length of the contraction pipe section is 0.8 to 1.5 times the diameter or width of the contraction pipe section;

[0019] The length of the inlet incoming flow section is 3 to 4 times its diameter or width; the diameter or width of the inlet outgoing flow section corresponds to that of the inlet incoming flow section.

[0020] Further, the self-excited oscillation cavity section includes an upper nozzle, a main self-excited oscillation cavity section connected in sequence to the upper nozzle, and a lower nozzle connected in sequence to the downstream of the main self-excited oscillation cavity section;

[0021] The upper nozzle is connected in series to the outlet of the inlet section, and the diameter or width of the upper nozzle is set corresponding to the diameter or width of the inlet outflow section; the diameter or width of the lower nozzle is 1.5 - 3 times that of the corresponding diameter or width of the upper nozzle.

[0022] The aspect ratio of the length to the diameter of the oscillation cavity in the main section of the self-excited oscillation cavity is between 2 and 5, and the length of the oscillation cavity is 5 - 7 times the diameter or width of the upper nozzle; the front wall of the oscillation cavity is vertically arranged, and the rear wall forms an angle of 60° with the horizontal.

[0023] Furthermore, the turbulent shear cavity wall is arranged corresponding to the lower nozzle; the turbulent shear block consists of an overflow channel formed by two rows of spaced trapezoidal baffles. Each row of trapezoidal baffles is spaced on the water cross-section and forms a gradually expanding channel with each other.

[0024] The length of the turbulent shear cavity section is 0.4 - 0.6 times the width. The bottom width of the trapezoidal baffle is 0.8 - 1.2 cm, the top width is 0.4 - 0.6 cm, and the trapezoidal height is 2.0 - 5.0 cm; the distance between the two rows of trapezoidal baffles is 2 - 3 cm.

[0025] Furthermore, the upstream opening diameter or width of the gradually expanding section is set to adapt to the outlet diameter or width of the turbulent shear cavity section. The expansion angle forms an angle of 10 - 15 degrees with the horizontal, and the length of the expansion section is 1 - 1.5 times the length of the lower nozzle.

[0026] The thickness of the baffle plate is at least 2 mm. The length of the baffle plate is 60 - 70% of the total cross-sectional width, and the baffle plate interval, that is, the channel width, is 3 - 7 mm; the outlet diameter or width of the curved channel pipe is 0.6 - 0.8 times the inlet diameter or width.

[0027] Furthermore, the expansion cavity section is an expansion cavity body with rounded corners. The expansion angle of the gradually expanding straight section forms an angle of 10 - 15 degrees with the horizontal. The length of the expansion section is 3 - 4 times the inlet diameter or width. The end point of the gradually expanding straight section is connected to an arc angle, and the arc R is equal to the inlet diameter or width. The left side of the arc is tangent to the straight line of the gradually expanding section, and the right side is tangent to the straight wall surface.

[0028] The diversion outlet section is arranged as a straight section, and its diameter or width is 1.1 - 1.2 times the inlet diameter or width of the expansion cavity section; the length of the diversion outlet section is 2 times its diameter or width.

[0029] Furthermore, for the application method of the aeration generation system of the self-excited oscillation turbulent shear device, the specific steps are as follows:

[0030] Step 1: Connect the water supply source through the water inlet pipe and connect the gas supply source through the air inlet pipe; both the water inlet pipe and the air inlet pipe are connected to a venturi tube and then connected to the self-excited oscillation turbulent shear device through a centrifugal pump and connected to a regulating valve through a pipeline, and connected to the bottom of the aeration tank through a pipeline downstream of the regulating valve; thus, an aeration generation system in a single overflow mode is formed.

[0031] Either the water inlet pipe is connected to the bottom of the aeration tank, and the air inlet pipe is connected to the air supply source; the water inlet pipe and the air inlet pipe are both connected to a venturi tube and then connected to a self-excited oscillation turbulent shear device through a centrifugal pump and connected to a regulating valve through a pipeline, and are connected to the upper middle part of the aeration tank through a pipeline downstream of the regulating valve; thus, an aeration generation system with a circulating flow pattern is formed.

[0032] Step Two: Water or other liquids undergo gas-liquid mixing in the venturi tube, and then flow through the centrifugal pump into the inlet incoming flow section and the inlet outgoing flow section and directly flow into the self-excited oscillation cavity section.

[0033] If in Step One, the air inlet pipe is directly connected to the inlet section, an inlet contraction pipe is provided in the inlet section and air guiding sections are provided on both sides of the inlet contraction pipe, and the air guiding sections are connected to the air inlet pipe; after entering the contraction part, gas-liquid mixing occurs due to negative pressure suction; among them, the gas-liquid ratio is 1% - 8%.

[0034] Step Three: The gas-liquid mixture after mixing enters the self-excited oscillation cavity section, the cross-sectional area expands and the flow velocity drops suddenly, resulting in a local pressure rise, but due to inertia in the flow field, the high-speed jet separates from the cavity wall to form a strong shear layer and a recirculation vortex, a continuous low-pressure zone is generated in the vortex core area, and the pressure at the edge of the cavity rises, forming a dynamic pressure gradient.

[0035] Step Four: Under the action of fluid inertia, the gas-liquid mixture is coupled with the secondary acceleration process of the downstream outlet contraction section of the self-excited oscillation cavity section, triggering self-excited oscillation: the instability of the outlet jet causes the pressure wave to reflect upstream, interacting periodically with the vortex shedding in the cavity, and finally forming a stable pressure pulsation.

[0036] Step Five: The bubbles in the gas-liquid mixture are broken under the action of inertial force during the periodic compression-expansion pulsation process, initially breaking the large bubbles into micron-sized bubbles; entering the turbulent shear block, where the turbulent shear block is arranged in a double-row spaced parallel and each row is arranged in series, thus forming a multiple pressure sudden change of contraction-expansion, the fluid accelerates to a high flow velocity, tears the bubbles through viscous shear force, and the low-pressure area in the throat further induces cavitation to generate new bubbles; the sudden rise in pressure in the expansion section causes the bubbles to collapse, releasing microjets and shock waves to break the bubbles secondary; among them, the parallel design improves the treatment flow rate, and the series structure gradually refines the bubbles to sub-micron size through multiple cycles.

[0037] Step Six: Subsequently, through the gradually expanding section to generate secondary flow in the curved channel pipe, enhancing the turbulence intensity and interface disturbance, the flow channel wall shear directly strips the surface of the bubbles, and at the same time the bubbles experience repeated stretching-folding deformation in the S-shaped path, promoting the instability and rupture of the interface, and the bubbles are further sheared to the order of hundreds of nanometers at this stage.

[0038] Step 7: After entering the expansion cavity section, the gradually expanding structure reduces the flow rate and restores the pressure, inhibiting bubble coalescence; the change in pressure gradient causes the surface tension of the residual bubbles to be unbalanced, and some of the incompletely broken bubbles undergo secondary collapse due to pressure oscillation in the gradually expanding section and finally stabilize into nanoscale bubbles; finally, they flow out through the diversion port section; after controlling the flow rate through the regulating valve, they enter the aeration tank.

[0039] The beneficial effects of the present invention are as follows:

[0040] Through the setting of the self-excited oscillation turbulent shear device of the present invention, the gas-liquid mixing is facilitated through the inlet section and the air entrainment section. Through the setting of the self-excited oscillation cavity section, the bubbles rupture during the periodic compression-expansion pulsation process, and through the setting of the turbulent shear cavity section, the high-shear-rate turbulent flow field in the cavity stretches the bubbles into thin liquid films, and the Rayleigh-Taylor instability induces fragmentation, while the centrifugal force of the recirculation vortex further throws the bubbles towards the low-pressure area of the vortex core to intensify the splitting; on the basis of inducing cavitation, the cavitation bubbles experience a violent expansion-contraction cycle in the high-pressure area or the low-pressure area at the outlet of the cavity, and microjets and shock waves are generated instantaneously during the collapse, directly tearing adjacent bubbles.

[0041] Secondary flow is generated in the curved channel pipe to enhance the turbulence intensity and interface perturbation. The bubbles experience repeated stretching-folding deformation in the S-shaped path, promoting interface instability and fragmentation. At this stage, the bubbles are further sheared to the hundreds of nanometer level;

[0042] Through the coordinated regulation of the microchannel geometric parameters and fluid dynamics of the present invention, precise control of the bubble size and distribution and particle size concentration are achieved, avoiding the particle size dispersion caused by random fragmentation or insufficient turbulent shear in the traditional method. Only a low-pressure pump is required to drive the fluid, without the need for high-pressure containers, high-power ultrasounds or electrode assemblies, resulting in a significant reduction in energy consumption, and there is no risk of electrode passivation or membrane pollution, making it suitable for fluids containing particulate matter or high turbidity. The proposed self-excited oscillation turbulent shear device has no microchannels and is also different from the existing nanobubble generators that must be equipped with release devices, and is not easily blocked.

[0043] Other features and advantages of the present invention will be described in the subsequent specification, and will be partially obvious from the specification, or will be understood by implementing the present invention; the main purpose and other advantages of the present invention can be achieved and obtained through the solutions specifically pointed out in the specification. Description of the Drawings

[0044] Figure 1 is a schematic diagram of an aeration generation system containing a self-excited oscillation turbulent shear device Figure 1 ;

[0045] Figure 2 is a schematic diagram of an aeration generation system containing a self-excited oscillation turbulent shear device Figure 2 ;

[0046] Figure 3 is a three-dimensional schematic diagram of a self-excited oscillation turbulent shear device;

[0047] Figure 4 is a plan schematic diagram of a self-excited oscillation turbulent shear device;

[0048] Figure 5 is a schematic diagram of the connection structure of a gradually expanding section, a curved channel section, an expansion cavity section, and a diversion outlet section;

[0049] Figure 6 is a schematic diagram of the inlet section structure;

[0050] Figure 7 is a schematic diagram of the self-excited oscillation cavity section structure;

[0051] Figure 8 is a schematic diagram of the turbulent shear cavity section structure;

[0052] Figure 9 is a schematic diagram of the simulation of the eddy current turbulent shear process inside the device;

[0053] Figure 10 is a distribution diagram of bubble diameter and concentration.

[0054] Reference numerals: 1 - self-excited oscillation turbulent shear device, 11 - inlet section, 111 - inlet incoming flow section, 112 - inlet contraction pipe, 113 - inlet outflow section, 12 - air-introducing section, 13 - self-excited oscillation cavity section, 131 - upper nozzle, 132 - main section of self-excited oscillation cavity, 133 - lower nozzle, 14 - turbulent shear cavity section, 141 - turbulent shear cavity wall, 142 - turbulent shear block, 15 - gradually expanding section, 16 - curved channel section, 161 - curved channel pipe, 162 - baffle plate, 17 - expansion cavity section, 18 - diversion outlet section, 2 - water inlet pipe, 3 - venturi tube, 4 - air inlet pipe, 5 - flowmeter, 6 - centrifugal pump, 7 - pressure gauge, 8 - pipeline, 9 - regulating valve, 10 - aeration tank. Detailed implementation manners

[0055] As Figures 1 to 8 shown, an aeration generation system containing a self-excited oscillation turbulent shear device includes a self-excited oscillation turbulent shear device 1, a water inlet unit and an air inlet unit connected upstream of the self-excited oscillation turbulent shear device 1, and an aeration tank 10 connected downstream of the self-excited oscillation turbulent shear device 1.

[0056] Among them, the water inlet unit is connected by a water inlet pipe 2 and a Venturi tube 3; the air inlet unit is connected downstream of an air inlet pipe 4 to a flow meter 5 and then to the Venturi tube 3 of the water inlet unit. The downstream of the Venturi tube 3 is connected to a centrifugal pump 6, and then connected to a self-excited oscillation turbulent shear device 1 through a pipeline 8. The water inlet pipe 2 is connected to a water supply source. The downstream of the self-excited oscillation turbulent shear device 1 is connected to a regulating valve 9 and connected to the bottom of an aeration tank 10 through a pipeline 8; or the water inlet pipe 2 is connected to the bottom of the aeration tank 10, and the downstream of the self-excited oscillation turbulent shear device 1 is connected to a regulating valve 9 and connected to the upper middle part of the aeration tank 10 through a pipeline 8.

[0057] In this embodiment, the water supply source of the water inlet pipe 2 can be tap water, river, lake or reservoir water, or water in a reactor or other flowing liquid phases, and it must be a Newtonian liquid, in which the particle size of suspended particulate matter does not exceed 2 mm. The Venturi tube 3 and the air induction section 12 are connected to a gas supply source. The gas supply sources of the two can be various gases such as air, oxygen, and carbon dioxide. Generally, a filter component should be arranged to remove particulate impurities in the inlet air to avoid damaging subsequent equipment. The flow meter 5 is selected according to the actual flow range requirements, and the working flow rate should be between 1 / 3 and 2 / 3 of the range.

[0058] In this embodiment, the gas-liquid ratio of the self-excited oscillation turbulent shear device 1 is 1% - 8%. If the gas-liquid ratio is too low, the gas content rate is low and the number of bubbles is small. If the gas-liquid ratio is too high, the gas content rate is high but the bubble diameter is too large. Nano-bubble generator. The gas-liquid mixture flows out from the pump outlet and enters the self-excited oscillation turbulent shear device 1, and self-excited oscillation turbulent shear occurs to achieve bubble fragmentation. The working flow rate of the self-excited oscillation turbulent shear device 1 depends on the matching pump, covering a wide flow range, from several liters per hour to hundreds of cubic meters per hour. Considering system foaming and pressure safety, the gauge pressure of the pressure gauge 7 of the self-excited oscillation turbulent shear device 1 is generally between 0.3 and 0.7 MPa. The self-excited oscillation turbulent shear device 1 can be connected to any liquid phase in the fields of chemical industry, environmental protection, new energy, agriculture, mining, etc., and is applicable to any scale in laboratories and engineering sites, but requires the working pressure and flow rate to be adapted.

[0059] In this embodiment, the working temperature and acid and alkali resistance of the self-excited oscillation turbulent shear device 1 depend on the material, generally made of nylon or stainless steel, with a working temperature of 4 - 70 °C and a pH of 3 - 9 applicable. The aeration tank 10 is a container for containing nano-bubble water, generally a lake, reservoir surface water body, bubble water tank or other forms of reactors.

[0060] In this embodiment, the self-excited oscillation turbulent shear device 1 includes an inlet section 11, a self-excited oscillation cavity section 13 connected downstream of the inlet section 11 in series, a turbulent shear cavity section 14 connected downstream of the self-excited oscillation cavity section 13 in series, a gradually expanding section 15 connected downstream of the turbulent shear cavity section 14 below, a curved channel section 16 connected downstream of the gradually expanding section 15 in series, an expansion cavity section 17 connected downstream of the curved channel section 16 in series, and a diversion outlet section 18 connected downstream of the expansion cavity section 17 in series; the turbulent shear cavity section 14 includes a turbulent shear cavity wall 141 and turbulent shear blocks 142 arranged inside the shear cavity wall, and the turbulent shear blocks 142 are arranged at intervals to form a gradually expanding channel; the curved channel section 16 includes a curved channel pipe 161 and a baffle 162 arranged inside the curved channel pipe 161; the baffle 162 is arranged at intervals alternately on both sides to form a multi-stage S-shaped channel.

[0061] In this embodiment, the inlet section 11 includes an inlet incoming flow section 111 and an inlet outgoing flow section 113, and the inlet incoming flow section 111 is connected to the centrifugal pump 6; both the inlet incoming flow section 111 and the inlet outgoing flow section 113 are arranged in a straight line, and the length of the inlet incoming flow section 111 is 3 to 4 times its diameter or width; the diameter or width of the inlet outgoing flow section 113 corresponds to that of the inlet incoming flow section 111. The inlet section 11 includes an inlet incoming flow section 111, an inlet contraction pipe 112 connected in series to the inlet incoming flow section 111, and an inlet outgoing flow section 113 connected in series to the inlet contraction pipe 112.

[0062] In this embodiment, air-introducing sections 12 are arranged on both sides of the inlet contraction pipe 112, and the air-introducing sections 12 are directly connected to the air supply source; the inlet incoming flow section 111, the inlet contraction pipe 112, and the inlet outgoing flow section 113 are all arranged in a straight line; the contraction angle of the inlet contraction pipe 112 forms an angle of 25 - 40 degrees with the horizontal, the diameter or width of the contraction pipe section is 1 / 2 to 3 / 4 of the diameter of the inlet incoming flow section 111, and the length of the contraction pipe section is 0.8 to 1.5 times the diameter or width of the contraction pipe section; the length of the inlet incoming flow section 111 is 3 to 4 times its diameter or width; the diameter or width of the inlet outgoing flow section 113 corresponds to that of the inlet incoming flow section 111.

[0063] In this embodiment, the self-excited oscillation cavity section 13 includes an upper nozzle 131, a self-excited oscillation cavity main section 132 connected in series to the upper nozzle 131, and a lower nozzle 133 connected in series to the downstream of the self-excited oscillation cavity main section 132; the upper nozzle 131 is connected in series to the outlet of the inlet section 11, and the diameter or width of the upper nozzle 131 corresponds to the diameter or width of the inlet outgoing flow section 113; the diameter or width of the lower nozzle 133 is 1.5 - 3 times the corresponding diameter or width of the upper nozzle 131; the aspect ratio of the long diameter of the oscillation cavity of the self-excited oscillation cavity main section 132 is between 2 and 5, and the length of the oscillation cavity is 5 to 7 times the diameter or width of the upper nozzle 131; the front wall of the oscillation cavity is vertically arranged, and the rear wall forms an angle of 60° with the horizontal.

[0064] In this embodiment, the turbulent shear cavity wall 141 is arranged corresponding to the lower nozzle 133; the turbulent shear block 142 is a flow passage composed of two rows of spaced trapezoidal baffles. Each row of trapezoidal baffles is spaced on the water cross-section and forms a gradually expanding channel with each other; the length of the turbulent shear cavity section 14 is 0.4 - 0.6 times the width, the bottom width of the trapezoidal baffle is 0.8 - 1.2 cm, the top width is 0.4 - 0.6 cm, and the trapezoidal height is 2.0 - 5.0 cm; the distance between the two rows of trapezoidal baffles is 2 - 3 cm.

[0065] In this embodiment, the upstream opening diameter or width of the gradually expanding section 15 is set to adapt to the outlet diameter or width of the turbulent shear cavity section 14, the expansion angle is 10 - 15 degrees with the horizontal, and the length of the expansion section is 1 - 1.5 times the length of the lower nozzle 133; the thickness of the baffle plate 162 is at least 2 mm, the length of the baffle plate 162 is 60 - 70% of the total cross-sectional width, the interval of the baffle plate 162, that is, the channel width, is 3 - 7 mm; the outlet diameter or width of the bent channel pipe 161 is 0.6 - 0.8 times the inlet diameter or width.

[0066] In this embodiment, the expansion cavity section 17 is an expansion cavity with rounded corners. The expansion angle of the gradually expanding straight section is 10 - 15 degrees with the horizontal, the length of the expansion section is 3 - 4 times the inlet diameter or width, the end of the gradually expanding straight section is connected to an arc angle, the arc radius R is equal to the inlet diameter or width, the left side of the arc is tangent to the straight line of the gradually expanding section 15, and the right side is tangent to the straight wall surface; the flow guiding outlet section 18 is set as a straight section, and its diameter or width is 1.1 - 1.2 times the inlet diameter or width of the expansion cavity section 17; the length of the flow guiding outlet section 18 is 2 times its diameter or width.

[0067] Combined Figures 1 to 10 As shown, the application method of the aeration generating system containing the self-excited oscillation turbulent shear device is as follows:

[0068] Step 1: Connect the water supply source through the water inlet pipe 2 and connect the gas supply source through the air inlet pipe 4; both the water inlet pipe 2 and the air inlet pipe 4 are connected to the venturi tube 3 and then connected to the self-excited oscillation turbulent shear device 1 through the centrifugal pump 6 and connected to the regulating valve 9 through the pipeline 8, and connected to the bottom of the aeration tank 10 through the pipeline 8 downstream of the regulating valve 9; thus, an aeration generating system with a single flow-through mode is formed.

[0069] Or the water inlet pipe 2 is connected to the bottom of the aeration tank 10, and the air inlet pipe 4 is connected to the gas supply source; both the water inlet pipe 2 and the air inlet pipe 4 are connected to the venturi tube 3 and then connected to the self-excited oscillation turbulent shear device 1 through the centrifugal pump 6 and connected to the regulating valve 9 through the pipeline 8, and connected to the upper middle part of the aeration tank 10 through the pipeline 8 downstream of the regulating valve 9; thus, an aeration generating system with a circulating flow mode is formed.

[0070] Step 2: Water or other liquid undergoes gas-liquid mixing in the venturi tube 3, and then flows through the centrifugal pump 6 into the inlet oncoming flow section 111 and the inlet outflow section 113, and directly flows into the self-excited oscillation cavity section 13.

[0071] If in Step 1, the intake pipe 4 is directly connected to the inlet section 11, an inlet contraction pipe 112 is provided in the inlet section 11, and air-introducing sections 12 are provided on both sides of the inlet contraction pipe 112. The air-introducing sections 12 are connected to the intake pipe 4; after entering the contraction part, gas-liquid mixing occurs due to negative-pressure suction.

[0072] Step 3: The gas-liquid mixture after mixing enters the self-excited oscillation cavity section 13. The cross-sectional area expands and the flow velocity drops suddenly, resulting in a local pressure rise. However, due to inertia in the flow field, the high-speed jet separates from the cavity wall to form a strong shear layer and a recirculation vortex. A continuous low-pressure zone is generated in the vortex core area, while the pressure rises at the edge of the cavity, forming a dynamic pressure gradient.

[0073] Step 4: Under the action of fluid inertia, the gas-liquid mixture is coupled with the secondary acceleration process of the downstream outlet contraction section of the self-excited oscillation cavity section 13, triggering self-excited oscillation: the instability of the outlet jet causes the pressure wave to reflect upstream, interacting periodically with the vortex shedding in the cavity, and finally forming a stable pressure pulsation.

[0074] Step 5: The bubbles in the gas-liquid mixture are broken under the action of inertial force during the periodic compression-expansion pulsation process, initially breaking the large bubbles into micron-sized bubbles; entering the turbulent shear block 142, where the turbulent shear block 142 is arranged in a double-row spaced parallel and in series in each row, thus forming a multiple pressure sudden change of contraction-expansion. The fluid accelerates to a high flow velocity, and the bubbles are torn by the viscous shear force. The low-pressure area in the throat further induces cavitation to generate new bubbles; the sudden rise in pressure in the expansion section causes the bubbles to collapse, releasing microjets and shock waves to break the bubbles secondary; among them, the parallel design improves the treatment flow rate, and the series structure gradually refines the bubbles to the submicron level through multiple cycles.

[0075] Step 6: Subsequently, after passing through the gradually expanding section 15, a secondary flow is generated in the curved channel pipe 161, enhancing the turbulence intensity and interface disturbance. The shear on the flow channel wall directly strips the surface of the bubbles. At the same time, the bubbles experience repeated stretching-folding deformation in the S-shaped path, promoting interface instability and rupture. At this stage, the bubbles are further sheared to the hundreds of nanometer level;

[0076] Step 7: After entering the expansion cavity section 17, the gradually expanding structure reduces the flow velocity and restores the pressure, suppressing bubble coalescence; the change in the pressure gradient causes the surface tension of the remaining bubbles to be unbalanced. Some of the bubbles that are not completely broken undergo secondary collapse due to pressure oscillation in the gradually expanding section 15, and finally stabilize as nanometer-sized bubbles; finally, they flow out through the diversion orifice section; after controlling the flow velocity corresponding to the regulating valve 9, they enter the aeration tank 10.

[0077] In this embodiment, a stainless steel self-excited oscillating turbulent shearing device 1 is used, the inlet is a 1-inch pipe, and a certain brand of centrifugal pump 6 is used to drive a 2m 3 / h water flow, gas-liquid ratio of 5%, after the equipment runs for 10 minutes, water samples are collected, and the prepared bubbles are tested for bubble size, concentration and potential using a nanoparticle tracking analyzer. Figure 10 As shown, the median diameter of the bubbles is 90.2nm, the concentration is 2.6×108 / mL, and the Zeta potential is around -10mV pure water background. The bubbles generated have high specific surface area, long residence time, interfacial activation effect and cavitation synergy characteristics.

[0078] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that a technician familiar with the technical field can think of within the technical scope disclosed in the present invention should be covered within the protection scope of the present invention.

Claims

1. An aeration generation system containing a self-excited oscillation turbulent shear device, characterized in that, It includes a self-excited oscillation turbulent shear device (1), a water inlet unit and an air inlet unit connected upstream of the self-excited oscillation turbulent shear device (1), and an aeration tank (10) connected downstream of the self-excited oscillation turbulent shear device (1); The self-excited oscillation turbulent shear device (1) includes an inlet section (11), a self-excited oscillation cavity section (13) connected downstream of the inlet section (11) in sequence, a turbulent shear cavity section (14) connected downstream of the self-excited oscillation cavity section (13) in sequence, a gradually expanding section (15) connected downstream of the turbulent shear cavity section (14) below, a bent channel section (16) connected downstream of the gradually expanding section (15) in sequence, an expansion cavity section (17) connected downstream of the bent channel section (16) in sequence, and a diversion outlet section (18) connected downstream of the expansion cavity section (17) in sequence; The turbulent shear cavity section (14) includes a turbulent shear cavity wall (141) and turbulent shear blocks (142) arranged inside the shear cavity wall. The turbulent shear blocks (142) are arranged at intervals to form a gradually expanding channel; The bent channel section (16) includes a bent channel pipe (161) and a baffle (162) arranged inside the bent channel pipe (161); the baffle (162) is arranged at intervals alternately on both sides and forms a multi-stage S-shaped channel.

2. The aeration generation system containing a self-excited oscillation turbulent shear device according to claim 1, characterized in that, The water inlet unit is connected by a water inlet pipe (2) and a venturi tube (3); the air inlet unit is connected downstream of an air inlet pipe (4) to a flow meter (5) and then to the venturi tube (3) of the water inlet unit. The downstream of the venturi tube (3) is connected to a centrifugal pump (6), and then is connected to the self-excited oscillation turbulent shear device (1) through a pipeline (8).

3. The aeration generation system containing a self-excited oscillation turbulent shear device according to claim 2, characterized in that, The water inlet pipe (2) is connected to a water supply source. The downstream of the self-excited oscillation turbulent shear device (1) is connected to a regulating valve (9) and is connected to the bottom of the aeration tank (10) through a pipeline (8); Or the water inlet pipe (2) is connected to the bottom of the aeration tank (10), the downstream of the self-excited oscillation turbulent shear device (1) is connected to a regulating valve (9) and is connected to the upper middle part of the aeration tank (10) through a pipeline (8).

4. The aeration generation system containing a self-excited oscillation turbulent shear device as described in claim 3, characterized in that The inlet section (11) includes an inlet incoming flow section (111) and an inlet outgoing flow section (113), and the inlet incoming flow section (111) is connected to the centrifugal pump (6); Both the inlet incoming flow section (111) and the inlet outgoing flow section (113) are arranged in a straight line. The length of the inlet incoming flow section (111) is 3 to 4 times its diameter or width; the diameter or width of the inlet outgoing flow section (113) corresponds to that of the inlet incoming flow section (111).

5. The aeration generation system containing a self-excited oscillation turbulent shear device according to claim 3, characterized in that, The inlet section (11) includes an inlet incoming flow section (111), an inlet contraction pipe (112) connected in sequence to the inlet incoming flow section (111), and an inlet outgoing flow section (113) connected in sequence to the inlet contraction pipe (112); Air guiding sections (12) are arranged on both sides of the inlet contraction pipe (112), and the air guiding sections (12) are directly connected to an air supply source; The inlet incoming flow section (111), the inlet contraction pipe (112) and the inlet outgoing flow section (113) are all arranged in a straight line; The contraction angle of the inlet contraction pipe (112) forms an angle of 25 - 40 degrees with the horizontal. The diameter or width of the contraction pipe section is 1 / 2 to 3 / 4 of the diameter of the inlet incoming flow section (111), and the length of the contraction pipe section is 0.8 to 1.5 times the diameter or width of the contraction pipe section; The length of the inlet incoming flow section (111) is 3 to 4 times its diameter or width; the diameter or width of the inlet outflow section (113) is set corresponding to the inlet incoming flow section (111).

6. The aeration generation system containing a self-excited oscillation turbulent shear device according to claim 4 or 5, characterized in that, The self-excited oscillation cavity section (13) includes an upper nozzle (131), a self-excited oscillation cavity main section (132) connected in sequence to the upper nozzle (131), and a lower nozzle (133) connected in sequence downstream of the self-excited oscillation cavity main section (132); The upper nozzle (131) is connected in sequence to the outlet of the inlet section (11), and the diameter or width of the upper nozzle (131) is set corresponding to the diameter or width of the inlet outflow section (113); the diameter or width of the lower nozzle (133) is 1.5 - 3 times the corresponding diameter or width of the upper nozzle (131); The aspect ratio of the long diameter of the oscillation cavity of the self-excited oscillation cavity main section (132) is between 2 and 5, and the length of the oscillation cavity is 5 to 7 times the diameter or width of the upper nozzle (131); the front wall of the oscillation cavity is vertically arranged, and the rear wall forms an angle of 60° with the horizontal.

7. The aeration generation system containing a self-excited oscillation turbulent shear device according to claim 6, characterized in that, The turbulent shear cavity wall (141) is set corresponding to the lower nozzle (133); the turbulent shear block (142) is a flow-through channel composed of two rows of spaced trapezoidal baffles. Each row of trapezoidal baffles is spaced on the water cross-section and forms a gradually expanding channel with each other; The length of the turbulent shear cavity section (14) is 0.4 to 0.6 times the width. The bottom width of the trapezoidal baffle is 0.8 to 1.2 cm, the top width is 0.4 to 0.6 cm, and the trapezoidal height is 2.0 to 5.0 cm; the distance between the two rows of trapezoidal baffles is 2 to 3 cm.

8. The aeration generation system containing a self-excited oscillation turbulent shear device as claimed in claim 7, characterized in that, The upstream opening diameter or width of the gradually expanding section (15) is set to adapt to the outlet diameter or width of the turbulent shear cavity section (14). The expansion angle forms an angle of 10 - 15 degrees with the horizontal, and the length of the expansion section is 1 to 1.5 times the length of the lower nozzle (133); The thickness of the baffle plate (162) is at least 2 mm. The length of the baffle plate (162) is 60 - 70% of the total cross-sectional width. The interval of the baffle plate (162), that is, the channel width, is 3 - 7 mm; the outlet diameter or width of the curved channel pipe (161) is 0.6 - 0.8 times the inlet diameter or width.

9. The aeration generation system containing a self-excited oscillation turbulent shear device according to claim 8, wherein The expansion cavity section (17) is an expansion cavity with rounded corners. The expansion angle of the gradually expanding straight section forms an angle of 10 - 15 degrees with the horizontal. The length of the expansion section is 3 to 4 times the inlet diameter or width. The end of the gradually expanding straight section is connected to an arc angle, and the arc R is equal to the inlet diameter or width. The left side of the arc is tangent to the straight line of the gradually expanding section (15), and the right side is tangent to the straight wall surface; The diversion outlet section (18) is set as a straight section, and its diameter or width is 1.1 - 1.2 times the inlet diameter or width of the expansion cavity section (17); the length of the diversion outlet section (18) is 2 times its diameter or width.

10. A method for applying an aeration generation system containing a self-excited oscillation turbulent shear device as described in claim 9, characterized in that, The specific steps are as follows: Step 1: Connect the water supply source through the water inlet pipe (2) and connect the gas supply source through the gas inlet pipe (4); both the water inlet pipe (2) and the gas inlet pipe (4) are connected to the venturi tube (3), then connected to the self-excited oscillation turbulent shear device (1) through a centrifugal pump (6) and connected to a regulating valve (9) through a pipeline (8), and connected to the bottom of the aeration tank (10) through the pipeline (8) downstream of the regulating valve (9); thus forming an aeration generation system in a single flow mode. Or the water inlet pipe (2) is connected to the bottom of the aeration tank (10), and the gas inlet pipe (4) is connected to the gas supply source; both the water inlet pipe (2) and the gas inlet pipe (4) are connected to the venturi tube (3), then connected to the self-excited oscillation turbulent shear device (1) through a centrifugal pump (6) and connected to a regulating valve (9) through a pipeline (8), and connected to the upper middle part of the aeration tank (10) through the pipeline (8) downstream of the regulating valve (9); thus forming an aeration generation system in a circulating flow mode. Step 2: Gas-liquid mixing occurs in the venturi tube (3) for water or other liquids, and then flows through the centrifugal pump (6) into the inlet incoming flow section (111) and the inlet outflow section (113) and directly flows into the self-excited oscillation cavity section (13); among them, the gas-liquid ratio is 1% - 8%. If in Step 1, the gas inlet pipe (4) is directly connected to the inlet section (11), an inlet contraction pipe (112) is provided in the inlet section (11), and air-introducing sections (12) are provided on both sides of the inlet contraction pipe (112), and the air-introducing sections (12) are connected to the gas inlet pipe (4); after entering the contraction part, gas-liquid mixing occurs due to negative pressure suction. Step 3: The gas-liquid mixture after mixing enters the self-excited oscillation cavity section (13), the cross-sectional area expands and the flow velocity drops suddenly, resulting in a local pressure rise, but due to inertia of the flow field, the high-speed jet separates from the cavity wall to form a strong shear layer and a recirculation vortex, a continuous low-pressure zone is generated in the vortex core area, while the pressure at the edge of the cavity rises, forming a dynamic pressure gradient. Step 4: Under the action of fluid inertia, the gas-liquid mixture is coupled with the secondary acceleration process of the downstream outlet contraction section of the self-excited oscillation cavity section (13) to trigger self-excited oscillation: the instability of the outlet jet causes the pressure wave to reflect upstream, interact with the periodic shedding of vortices in the cavity, and finally form a stable pressure pulsation. Step 5: The bubbles in the gas-liquid mixture are broken under the action of inertial force during the periodic compression-expansion pulsation process, initially breaking the large bubbles into micron-sized bubbles; entering the turbulent shear block (142), where the turbulent shear block (142) is arranged in a double-row interval in parallel and each row is arranged in series, thus forming a multiple pressure sudden change of contraction-expansion, the fluid accelerates to a high flow velocity, tears the bubbles through viscous shear force, and the low-pressure area in the throat further induces cavitation to generate new bubbles; the sudden rise in pressure in the expansion section causes the bubbles to collapse, releasing microjets and shock waves to break the bubbles secondary; among them, the parallel design improves the treatment flow rate, and the series structure gradually refines the bubbles to sub-micron size through multiple cycles. Step 6: Subsequently, secondary flow is generated in the gradually expanding section (15) and into the curved channel tube (161), enhancing the turbulence intensity and interface perturbation. The shear force on the channel wall directly strips the surface of the bubbles. At the same time, the bubbles experience repeated stretching and folding deformation in the S-shaped path, promoting interface instability and rupture. At this stage, the bubbles are further sheared to the nanometer scale of hundreds of nanometers. Step 7: After entering the expansion cavity section (17), the gradually expanding structure reduces the flow velocity and restores the pressure, suppressing bubble coalescence. The change in the pressure gradient causes the surface tension of the remaining bubbles to be unbalanced. Some of the bubbles that are not completely broken undergo secondary collapse due to pressure oscillation in the gradually expanding section (15) and finally stabilize into nanoscale bubbles. Finally, they flow out through the diversion port section and enter the aeration tank (10) after the flow velocity is correspondingly controlled by the regulating valve (9).

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