Multi-cavity parallel micro-cyclone micro-nano bubble generating device and micro-nano bubble generating method

Abstract

This invention discloses a multi-cavity parallel micro-swirling micro / nano bubble generator and a method for generating micro / nano bubbles. The generator includes a generator shell with two opposing ends. One end of the generator shell has a liquid inlet, and the other end has several parallel Venturi cavities arranged to refine the bubbles under cavitation. This invention organically synergizes multi-cavity parallel swirling shearing with parallel Venturi cavitation, utilizing the high-speed swirling field formed by multiple swirling chambers to initially shear the gas into micro / nano-scale bubbles. These bubbles are then uniformly mixed through a gas-liquid mixing chamber and fed into the parallel Venturi cavities for secondary cavitation refinement. This ensures the initial generation of fine bubbles while continuously reducing bubble size and increasing the proportion of nano-bubbles through secondary cavitation. Furthermore, the multi-cavity parallel design facilitates increased processing capacity and reduced flow resistance, as well as compact device design and low-cost manufacturing.

Description

Technical Field

[0001] This invention relates to the field of micro-nano bubble generation and enhanced mass transfer technology, specifically to a multi-cavity parallel micro-swirling micro-nano bubble generator and a method for generating micro-nano bubbles. Background Technology

[0002] Micro- and nanobubbles typically refer to bubbles with diameters ranging from 1 nm to 100 μm. Compared to conventional bubbles, they possess advantages such as large specific surface area, strong interfacial activity, long residence time in liquids, and high mass transfer efficiency, attracting widespread attention in fields such as water treatment, environmental engineering, aquaculture, chemical reaction enhancement, and agricultural irrigation. Especially in the enhancement of gas-liquid mass transfer processes, how to efficiently and stably generate high-concentration nanobubbles has become a key technical challenge in current research and engineering applications.

[0003] Existing methods for preparing micro and nanobubbles mainly include dissolved gas release, microporous aeration, and bubble generation methods based on hydrodynamics. Among these, dissolved gas release involves dissolving gas in a liquid under high pressure and then releasing it under reduced pressure to form microbubbles. While this method is mature, it generally suffers from complex equipment, high energy consumption, and a low proportion of nanobubbles generated. Microporous aeration disperses gas into fine bubbles using microporous materials, but this method is prone to clogging, and the bubble size is limited by the pore size, making it difficult to stably obtain nanoscale bubbles.

[0004] In recent years, bubble generation methods based on fluid dynamics effects have gradually become a research hotspot due to their lack of the need for complex external physical fields, relatively simple structures, and ease of engineering scale-up. Among them, swirling shearing and Venturi cavitation are two typical technical approaches.

[0005] The micro / nanobubble generating device and method described in announcement number CN110479127B employs a combination of jet and swirling flow techniques. The fluid first forms a jet through a jet tube, then collides with the gas in the front throat tube to generate shear and form micron-sized bubbles. The bubbles then pass through guide vanes to form a tangential swirling flow and enter the cyclone compression tube for secondary cutting. Finally, the bubbles undergo a third refinement through the rear throat tube and diffuser tube. This design embodies the idea of ​​combining multi-stage processing and multiple mechanisms. However, the swirling section uses a spiral groove structure, which makes the manufacturing process more complex.

[0006] The multi-stage swirling microbubble releaser and dissolved gas release system, with announcement number CN109502780B, adopts a unique structure of multiple swirling chambers nested sequentially from the inside out. The multiple swirling chambers are connected from the outside to the inside, and the inner width decreases from the outside to the inside. During the rotation and transportation of dissolved gas water in the swirling chambers, the pressure energy decreases and is converted into kinetic energy, releasing more gas. This nested structure is in stark contrast to the parallel multi-chamber design adopted in this invention.

[0007] The announcement number CN218249541U describes a vortex-driven micro / nano bubble generator and a high-density circulating aquaculture pure oxygen dissolving device. It adopts a conical gas chamber and swirling air inlet structure, which increases the dissolved oxygen in the liquid through multiple high-speed gas-liquid shearing processes, and the bubble / water volume ratio can reach about 50%.

[0008] The announcement number CN112408584B discloses a swirling micro / nano bubble generator and its generation method. It adopts a static multi-stage blade cascade with a hollow blade structure in the last stage. The blade cascade is used to convert the water flow from a straight flow to a swirling flow. By changing the installation angle of the multi-stage blade cascade, the head provided by the water pump is efficiently converted into a high-speed circumferential water flow velocity in a short flow. Micro / nano bubbles are generated by the shearing of the gas by the rotating water flow.

[0009] In summary, while existing technologies have made significant progress in the generation of micro and nano bubbles, they still have the following shortcomings: (1) Devices that rely solely on swirling shear can generate small bubbles, but the bubble size distribution is relatively wide, and the shearing capacity of a single swirling chamber is limited when processing large flow rates. For example, although patent CN112408584B adopts a multi-stage blade structure, it is still a single flow channel design, and the processing capacity is limited by the size of a single chamber.

[0010] (2) Devices that rely solely on Venturi cavitation often have low nanobubble yields due to the limited intensity of single-stage cavitation. While multi-stage cascaded cavitation structures can enhance the effect to some extent, they have high flow resistance and high energy consumption.

[0011] (3) In partially combined devices, different functional units are often arranged in series, resulting in greater flow resistance.

[0012] (4) The highly integrated multi-module device integrates multiple crushing mechanisms, but the system is complex and contains multiple independent functional units, which is not conducive to the compactness and low-cost manufacturing of the device.

[0013] Currently, there is a lack of a compact device that can achieve efficient initial breakup through multi-channel parallel connection, continuously refine bubbles through subsequent multi-stage cavitation, and simultaneously maintain low flow resistance and good functional unit matching. Therefore, this invention proposes a multi-cavity parallel micro-swirling micro / nano bubble generator and a method for generating micro / nano bubbles. Summary of the Invention

[0014] The purpose of this invention is to provide a multi-cavity parallel micro-swirling micro-nano bubble generator and a method for generating micro-nano bubbles in order to solve the above-mentioned problems and overcome the defects of the prior art, as detailed below.

[0015] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a multi-cavity parallel micro-swirling micro-nano bubble generator, comprising a generator housing having two opposing ends, one end of the generator housing being provided with a liquid phase inlet, and the other end of the generator housing being provided with a plurality of parallel Venturi cavities for refining bubbles under cavitation. The generator housing has adjacent liquid distribution chambers and gas-liquid mixing chambers inside. The liquid distribution chamber has several parallel swirling chambers. The liquid inlet is connected to the liquid distribution chamber. The swirling chamber includes a main chamber with two opposite ends. One end of the main chamber has an air inlet end, and the other end of the main chamber has a first contraction section and an expansion nozzle in sequence. Each of the aforementioned swirling chambers is provided with a liquid phase swirling inlet and is connected to the liquid distribution chamber through the liquid phase swirling inlet. After the liquid enters the swirling chamber through the liquid phase swirling inlet, a high-speed swirling field is formed in the swirling chamber. The gas phase is sheared and broken in the swirling chamber and then enters the gas-liquid mixing chamber through the jet, and the gas and liquid are fully mixed under the action of turbulence. The gas-liquid mixing chamber is connected to the Venturi cavity, and the Venturi cavity is used to refine the gas-liquid mixture flowing through the gas-liquid mixing chamber under cavitation. The Venturi cavity has a second contraction section at the end facing the gas-liquid mixing chamber and an expansion section along the direction away from the gas-liquid mixing chamber. In some embodiments of the first aspect, the generator housing is provided with a gas phase inlet, which is connected to each swirling chamber via a gas branch pipe.

[0016] In some embodiments of the first aspect, the second contraction section of the Venturi cavity and the first contraction section of the vortex chamber are both arc-shaped and of the same size.

[0017] In some embodiments of the first aspect, the Venturi cavities are provided with four or more, the expansion angle of the expansion section is 6° to 15°, and the ratio of the diameter of the smallest end to the diameter of the largest end of the expansion section is 0.2 to 0.4.

[0018] In some embodiments of the first aspect, the ratio of the minimum cross-sectional diameter of the first contraction section of the swirling chamber to the diameter of the main chamber is 0.2 to 0.5, and the expansion angle of the expansion nozzle is 35° to 55°.

[0019] In some embodiments of the first aspect, the liquid distribution chamber is provided with a diversion cone for uniformly distributing the liquid entering therein to each swirling chamber.

[0020] In some embodiments of the first aspect, the aspect ratio of the cross-section of the liquid phase swirl inlet is 0.1 to 0.5.

[0021] Secondly, the present invention also provides a method for generating multi-cavity parallel micro-swirling micro-nano bubbles, comprising the following steps: S1. Pressurized liquid enters the liquid distribution chamber, is evenly distributed by the flow divider cone, and then enters each parallel swirling chamber through the liquid phase swirling inlet, forming a high-speed swirling field in the swirling chamber. S2. The gas is diverted through the gas phase inlet to each gas branch pipe and then introduced into the swirling chamber, where a stable group of rotating bubbles can be formed in the high-speed swirling field. S3. The rotating bubble group flows through the first contraction section and the expansion nozzle under the liquid drive in the swirling chamber. After being accelerated in the first contraction section, it enters the expansion nozzle and is broken into micro-nano bubbles under the action of swirling shear and is injected into the gas-liquid mixing chamber. S4. After the micro-nano bubbles and liquid are mixed in the gas-liquid mixing chamber, they enter the parallel Venturi cavities and flow through the second contraction section and expansion section of each Venturi cavity in sequence. Under the action of cavitation, the bubbles are further refined, thereby releasing high-concentration nano bubbles.

[0022] In some embodiments of the second aspect, in step S1, the injection pressure of the liquid entering the liquid distribution chamber is not less than 0.2 MPa, and the gas pressure is at least 0.1 MPa higher than the liquid pressure.

[0023] The beneficial effects are: 1. This invention utilizes a high-speed swirling flow field formed by multiple swirling chambers to initially shear gas into micro- and nano-sized bubbles through the organic synergy of multi-cavity parallel swirling shearing and parallel Venturi cavitation. The gas is then uniformly mixed through a gas-liquid mixing chamber and fed into parallel Venturi chambers for secondary cavitation refinement. This ensures the initial generation of fine bubbles and continuously reduces bubble size and increases the proportion of nano-bubbles through secondary cavitation. At the same time, the multi-cavity parallel design is conducive to the amplification of processing capacity and the reduction of flow resistance, as well as the compactness and low-cost manufacturing of the device. This invention can solve the problems of low nano-bubble concentration, complex structure, or high energy consumption in existing technologies.

[0024] 2. The parallel swirling chambers have strong primary bubble-forming ability. Multiple swirling chambers are connected in parallel, and each swirling chamber forms an independent high-speed swirling field, which causes the gas to form a group of rotating bubbles in the center of each chamber and be sheared at high speed locally. This can generate a large number of primary micro-nano bubbles in a relatively short flow path.

[0025] 3. The parallel Venturi chambers have a clear secondary refinement effect. After the primary micro-nano bubbles generated in the swirling section enter the parallel Venturi chambers, they are further refined under the action of low-pressure cavitation in the throat, pressure recovery in the expansion section, cavitation bubble collapse and turbulent shearing, which is conducive to increasing the proportion of nano bubbles and bubble concentration.

[0026] 4. Both the swirl chamber and the venturi chamber are arranged in parallel. Compared with the multi-stage series structure, this can reduce the overall flow resistance and allow for modular expansion of processing capacity by increasing or decreasing the number of parallel units.

[0027] 5. The gas-liquid mixing chamber is located between the swirling chamber and the venturi cavity, which can buffer, mix and homogenize multiple micro-nano bubble jets, providing a more uniform inlet two-phase flow for the venturi cavity and improving the stability of venturi cavitation refinement.

[0028] 6. By adjusting the liquid inlet pressure, gas supply pressure, gas flow rate, number of swirling chambers, number of Venturi chambers, and Venturi throat size, the swirling shear intensity and cavitation intensity can be controlled, thereby meeting the requirements of different application scenarios for micro-nano bubble particle size and concentration. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is the front view of the present invention; Figure 2 This is the present invention. Figure 1 AA cross-section view; Figure 3 This is the present invention. Figure 1 A three-dimensional partial cross-sectional view; Figure 4 This is a first schematic diagram of the vortex chamber structure of the present invention; Figure 5 This is a second schematic diagram of the vortex chamber structure of the present invention; Figure 6 This is a schematic diagram of the Venturi cavity of the present invention.

[0031] The reference numerals in the attached drawings are explained as follows: 100, generator housing; 110, liquid inlet; 120, liquid distribution chamber; 130, swirling chamber; 131, air inlet end; 132, first contraction section; 133, expansion nozzle; 134, main chamber; 140, gas-liquid mixing chamber; 150, venturi cavity; 151, second contraction section; 152, expansion section; 160, liquid swirling inlet; 170, gas inlet; 180, gas branch pipe; 190, flow divider cone. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0033] It should be noted that when an element is said to be "fixed" to another element, it can be directly on the other element or there may be an intervening element. When an element is said to be "connected" to another element, it can be directly connected to the other element or there may be an intervening element. Conversely, when an element is said to be "directly" on another element, there is no intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0034] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the template description is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0037] It should be emphasized that this application is based on extensive and in-depth research that found existing micro-nano bubble generators have technical problems such as low nanobubble yield, wide bubble size distribution, large flow resistance of multi-level series structure, and poor matching of different functional units.

[0038] The technical concept of this application is to achieve efficient generation of micro- and nano-bubbles by organically combining parallel multi-cavity swirling shearing and crushing with parallel Venturi cavitation refinement, thereby significantly increasing the concentration of nano-bubbles, reducing flow resistance and energy consumption, and improving gas-liquid mass transfer efficiency.

[0039] Example 1: See Figures 1-6 As shown, the present invention provides a multi-cavity parallel micro-swirling micro-nano bubble generator, including a generator housing 100, which has two opposite ends. One end of the generator housing 100 is provided with a liquid phase inlet 110, and the other end of the generator housing 100 is provided with a plurality of parallel Venturi cavities 150 for refining bubbles under cavitation. The generator housing 100 has adjacent liquid distribution chambers 120 and gas-liquid mixing chambers 140 inside, with the liquid inlet 110 communicating with the liquid distribution chamber 120. Exemplarily, the gas-liquid mixing chamber 140 is a frustum-shaped cavity used to receive micro-nano bubble jets from various swirling chambers 130. The gas-liquid two-phase jets generated by different swirling chambers 130 collide and mix with each other in the gas-liquid mixing chamber 140, achieving thorough and uniform mixing of gas and liquid under turbulent action, providing a stable inlet flow field for subsequent Venturi cavitation treatment.

[0040] The liquid distribution chamber 120 is provided with several parallel swirling chambers 130. Each swirling chamber 130 is provided with a liquid phase swirling inlet 160 and is connected to the liquid distribution chamber 120 through the liquid phase swirling inlet 160. After the liquid enters the swirling chamber 130 through the liquid phase swirling inlet 160, a high-speed swirling field is formed in the swirling chamber 130. The gas phase is sheared and broken in the swirling chamber 130 and then enters the gas-liquid mixing chamber 140 through the jet, and the gas and liquid are fully mixed under the action of turbulence. The gas-liquid mixing chamber 140 is connected to the venturi cavity 150, which is used to refine the bubbles of the gas-liquid mixture flowing through the gas-liquid mixing chamber 140 under cavitation.

[0041] In these embodiments, such as Figure 2 and Figure 3 As shown, a flow-diverting cone 190 with a conical outline is provided in the center of the liquid distribution chamber 120. The cone angle is 20° to 45°. It is used to evenly distribute the liquid entering it to each vortex chamber 130. For example, the cone angle of the flow-diverting cone 190 can also be 25°, 30°, 35°, or 40°. The cone apex of the flow-diverting cone 190 faces the liquid inlet 110.

[0042] In some embodiments, the number of swirling chambers 130 is six, arranged in a circular array around the central axis of the flow divider cone 190. Each swirling chamber 130 has a cylindrical cavity structure, and the aspect ratio of the liquid phase swirling inlet 160 is 0.1–0.5, specifically 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, or 0.45, to ensure that the liquid enters the swirling chamber 130 at high speed in the tangential direction, thereby forming a stable high-speed swirling field. Furthermore, the number of swirling chambers 130 is not limited to six; it can also be one, two, three, four, or five. When there is only one swirling chamber 130, the overall structure is simple and compact, suitable for low-flow-rate processing conditions. When there are two, three, four, five, or more swirling chambers, they can be arranged in parallel. Those skilled in the art can select the number of swirling chambers according to actual process requirements.

[0043] In some embodiments, the swirling chamber 130 includes a main chamber 134 with two opposing ends. One end of the main chamber 134 is provided with an air inlet 131, and the other end of the main chamber 134 is provided with a first contraction section 132 and an expansion nozzle 133 in sequence. The generator housing 100 is provided with a gas phase inlet 170, which is connected to the air inlet 131 of each swirling chamber 130 through a gas branch pipe 180. Exemplarily, the air inlet 131 is located at the center of the end of the swirling chamber 130. The swirling chamber 130 is connected to the gas phase inlet 170 in sequence through the air inlet 131 and the gas branch pipe 180. Specifically, after the gas enters the gas branch pipe 180 through the gas phase inlet 170, it is distributed to the air inlet 131 of each swirling chamber 130. When gas enters the swirling chamber 130 from the inlet 131, it is drawn into the center of the swirling field by the high-speed rotating liquid, forming a stable group of rotating bubbles.

[0044] Based on the aforementioned embodiments, the ratio of the minimum cross-sectional diameter of the first contraction section 132 of the swirling chamber 130 to the diameter of the main chamber 134 is 0.2 to 0.5, specifically, it can be 0.25, 0.30, 0.35, 0.40, or 0.45. The expansion angle of the expansion nozzle 133 is 35° to 55°, specifically 40°, 45°, or 50°. Under the action of the high-speed swirling flow field, the rotating bubble group is carried by the liquid and accelerated in the first contraction section 132 before entering the expansion nozzle 133. During this process, the rotating bubble group is subjected to the strong swirling shearing action of the high-speed swirling flow field formed by the liquid phase swirling inlet 160 and the sudden pressure change of the first contraction section 132 and the expansion nozzle 133, breaking into micron-sized or even nano-sized fine bubbles, which are ejected from the expansion nozzle 133 in the form of a high-speed jet.

[0045] In some embodiments, such as Figure 2 , Figure 3 and Figure 6 As shown, the Venturi cavity 150 has a second contraction section 151 at one end facing the gas-liquid mixing chamber 140 and an expansion section 152 formed in the direction away from the gas-liquid mixing chamber 140. The second contraction section 151 of the Venturi cavity 150 and the first contraction section 132 of the vortex chamber 130 are both arc-shaped and have the same size. There are four or more Venturi cavities 150. The expansion angle of the expansion section 152 is 6° to 15°, and the ratio of the diameter of the smallest end to the diameter of the largest end of the expansion section 152 is 0.2 to 0.4. Each Venturi cavity 150 has the same structural parameters. For example, there are 13 Venturi cavities 150. The expansion angles of the expansion sections 152 are 7°, 8°, 9°, 10°, 11°, 12°, 13°, and 14°. The ratio of the minimum diameter to the maximum diameter of the expansion section 152 is 0.25, 0.30, and 0.35, respectively. The specific working process of the Venturi cavities 150 is as follows: after the gas-liquid mixture enters the parallel Venturi cavities 150, the flow velocity increases and the pressure decreases when it flows through the second contraction section 151 of each Venturi cavity 150. The pressure reaches the minimum near the minimum diameter, inducing cavitation. Subsequently, in the expansion section 152, the pressure recovers, the cavitation bubbles collapse, and strong microjets and shock waves are generated to break and refine the bubbles a second time, further reducing the bubble size and significantly increasing the concentration of nanobubbles. The high-concentration nanobubble liquid after being treated by the parallel Venturi cavities 150 is discharged from the opening of the expansion section 152.

[0046] Example 2: This example proposes a method for generating multi-cavity parallel micro-swirling micro-nano bubbles, including the following steps: Step 1: The injection pressure of the liquid entering the liquid distribution chamber 120 shall not be less than 0.2 MPa, and the gas pressure shall be at least 0.1 MPa higher than the liquid pressure. Specifically, the liquid pump is turned on, allowing pressurized purified water to enter the liquid distribution chamber 120 at a pressure of 0.5 MPa. After being evenly distributed by the diversion cone 190 with a cone angle of 30°, the purified water enters six parallel swirling chambers 130 through the liquid phase swirling inlet 160, forming a high-speed swirling field within the swirling chambers 130. Since the cross-sectional width-to-height ratio of the liquid phase swirling inlet 160 is 0.3, the swirling intensity can be adjusted by the liquid pressure.

[0047] Step 2: Turn on the gas source and adjust the gas pressure to 0.65MPa (0.15MPa higher than the liquid pressure). Divert the gas through the gas inlet 170 to each gas branch pipe 180 and introduce it into the swirling chamber. A stable group of rotating bubbles can be formed in the high-speed swirling field.

[0048] Step 3: Driven by the liquid within the swirling chamber 130, the rotating bubble swarm flows through the first contraction section 132 and the expansion nozzle 133. After accelerating in the first contraction section 132, it enters the expansion nozzle 133. Upon reaching the throat, the flow velocity reaches its maximum and the pressure drops to its minimum. After entering the expansion nozzle 133, the pressure rises sharply, and the rotating bubble swarm breaks down into micro- and nano-bubbles, i.e., micron- and nano-sized bubbles, under the combined action of strong swirling shearing and cavitation effects. The gas-liquid two-phase jet containing micro- and nano-bubbles is ejected at high speed from the expansion nozzle 133 and enters the gas-liquid mixing chamber 140.

[0049] Step 4: Micro-nano bubble jets from six swirling chambers 130 collide and mix with each other in the gas-liquid mixing chamber 140, achieving thorough and uniform mixing of gas and liquid under turbulence. The uniformly mixed gas-liquid two-phase flow then enters the parallel-arranged Venturi cavities 150, sequentially flowing through the second contraction section 151 and expansion section 152 of each Venturi cavity 150. In the second contraction section 151, the gas-liquid mixture experiences increased velocity and decreased pressure, reaching its lowest pressure near the throat, inducing cavitation and generating a large number of cavitation bubbles. Subsequently, the pressure recovers in the expansion section 152, causing the cavitation bubbles to collapse, generating strong micro-jet streams and shock waves. This process further breaks up and refines the bubbles, reducing their size. Finally, a high-concentration nanobubble liquid is obtained from the outlet of the expansion section 152.

[0050] Testing revealed that over 85% of the bubbles generated by the method in this embodiment were nanobubbles with a diameter of less than 1 μm, and the dissolved oxygen concentration was increased by more than 40% compared to conventional aeration methods. The testing parameters and results are shown in Tables 1 and 2.

[0051]

[0052]

[0053] Example 3: This example is basically the same as Example 2, except that the operating parameters are adjusted to control the bubble size and concentration.

[0054] Specifically: the liquid pressure is adjusted to 0.8 MPa, the gas pressure is adjusted to 1.0 MPa (the gas pressure is 0.2 MPa higher than the liquid pressure), the number of vortex chambers 130 is reduced to 4, and the number of parallel Venturi chambers 150 is reduced to 9.

[0055] Due to the increased liquid pressure, the swirling intensity within the swirling chamber 130 increases, resulting in stronger shearing forces on the rotating bubble cluster and finer bubbles generated after initial breakup. Simultaneously, a greater number of swirling chambers 130 and venturi cavities 150 are connected in parallel. While maintaining a constant total flow rate, the flow velocity in a single swirling chamber 130 or venturi cavity 150 decreases relatively, but the overall processing capacity increases. Furthermore, the multiple jets generated by the various swirling chambers 130 or venturi cavities 150 collide with each other within the gas-liquid mixing chamber 140, further enhancing the mixing and breakup effects.

[0056] Testing revealed that over 60% of the bubbles generated by the method in this embodiment were nanobubbles with a diameter less than 500 nm, and the overall gas mass transfer coefficient was improved by approximately 10% compared to Example 2. This method is suitable for applications requiring extremely high mass transfer efficiency, such as chemical intensification reactions and the treatment of high-concentration organic wastewater. The testing parameters and results are shown in Tables 3 and 4.

[0057]

[0058]

[0059] Comparative Example 1: Conventional Micropore Aeration Method To illustrate the technical effectiveness of the device of the present invention, a conventional microporous aeration method was used as a comparative example. In Comparative Example 1, a microporous aeration head with a pore size of 10 μm was used, and aeration treatment was carried out under the same water volume, the same operating time, and a similar air intake. The test results of Comparative Example 1 are shown in Table 5.

[0060]

[0061]

[0062] As shown in Table 6, compared with conventional microporous aeration methods, Examples 2 and 3 of this invention can significantly reduce bubble particle size, increase the proportion of bubbles smaller than 1 μm, and significantly improve the concentration of micro / nano bubbles and dissolved oxygen. This is because this invention does not simply rely on microporous dispersion or single-stage cavitation. Instead, it first uses multiple parallel swirling chambers 130 to form a high-speed swirling shear, achieving primary gas fragmentation. Then, after being uniformly distributed through the gas-liquid mixing chamber 140, the gas enters the parallel Venturi chambers 150, where secondary refinement is achieved through low-pressure cavitation in the throat of the second contraction section 151 and the collapse of cavitation bubbles in the expansion section 152 of the Venturi chamber 150. Therefore, this invention can improve the efficiency of nanobubble generation while maintaining low flow resistance and good processing capacity.

[0063] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A multi-cavity parallel micro-swirling micro-nano bubble generator, characterized in that: It includes a generator housing with two opposing ends. One end of the generator housing is provided with a liquid phase inlet, and the other end of the generator housing is provided with a plurality of parallel Venturi cavities for refining bubbles under cavitation. The generator housing has adjacent liquid distribution chambers and gas-liquid mixing chambers inside. The liquid phase inlet is connected to the liquid distribution chamber. The liquid distribution chamber has several parallel swirling chambers. The swirling chamber includes a main chamber. The main chamber has two opposite ends. One end of the main chamber is provided with an air inlet. The other end of the main chamber is provided with a first contraction section and an expansion nozzle in sequence. Each of the aforementioned swirling chambers is provided with a liquid phase swirling inlet and is connected to the liquid distribution chamber through the liquid phase swirling inlet. After the liquid enters the swirling chamber through the liquid phase swirling inlet, a high-speed swirling field is formed in the swirling chamber. The gas phase is sheared and broken in the swirling chamber and then enters the gas-liquid mixing chamber through the jet, and the gas and liquid are fully mixed under the action of turbulence. The gas-liquid mixing chamber is connected to the Venturi cavity, and the Venturi cavity is used to refine the gas-liquid mixture flowing through the gas-liquid mixing chamber under cavitation. The Venturi cavity has a second contraction section at one end facing the gas-liquid mixing cavity and an expansion section in the direction away from the gas-liquid mixing cavity.

2. The multi-cavity parallel micro-swirling micro-nano bubble generator according to claim 1, characterized in that: The generator housing is provided with a gas phase inlet, which is connected to each swirling chamber through a gas branch pipe.

3. The multi-cavity parallel micro-swirling micro-nano bubble generator according to claim 1, characterized in that: The second contraction section of the Venturi cavity and the first contraction section of the vortex chamber are both arc-shaped and have the same size.

4. The multi-cavity parallel micro-swirling micro-nano bubble generator according to claim 1, characterized in that: The Venturi cavity is provided with four or more, the expansion angle of the expansion section is 6° to 15°, and the ratio of the diameter of the smallest end to the diameter of the largest end of the expansion section is 0.2 to 0.

4.

5. The multi-cavity parallel micro-swirling micro-nano bubble generator according to claim 1, characterized in that: The ratio of the minimum cross-sectional diameter of the first contraction section of the swirling chamber to the diameter of the main chamber is 0.2 to 0.5, and the expansion angle of the expansion nozzle is 35° to 55°.

6. The multi-cavity parallel micro-swirling micro-nano bubble generator according to claim 1, characterized in that: The liquid distribution chamber is equipped with a flow-diverting cone for uniformly distributing the liquid entering it to each vortex chamber.

7. The multi-cavity parallel micro-swirling micro-nano bubble generator according to claim 1, characterized in that: The aspect ratio of the cross-section of the liquid phase vortex inlet is 0.1 to 0.

5.

8. A method for generating multi-cavity parallel micro-swirling micro-nano bubbles, comprising a multi-cavity parallel micro-swirling micro-nano bubble generator having a generator housing, a liquid distribution chamber, a swirling chamber, a gas-liquid mixing chamber, and a Venturi chamber, characterized in that: Includes the following steps: S1. Pressurized liquid enters the liquid distribution chamber, is evenly distributed by the flow divider cone, and then enters each parallel swirling chamber through the liquid phase swirling inlet, forming a high-speed swirling field in the swirling chamber. S2. The gas is diverted through the gas phase inlet to each gas branch pipe and then introduced into the swirling chamber, where a stable group of rotating bubbles can be formed in the high-speed swirling field. S3. The rotating bubble group flows through the first contraction section and the expansion nozzle under the liquid drive in the swirling chamber. After being accelerated in the first contraction section, it enters the expansion nozzle and is broken into micro-nano bubbles under the action of swirling shear and is injected into the gas-liquid mixing chamber. S4. After the micro-nano bubbles and liquid are mixed in the gas-liquid mixing chamber, they enter the parallel Venturi cavities and flow through the second contraction section and expansion section of each Venturi cavity in sequence. Under the action of cavitation, the bubbles are further refined, thereby releasing high-concentration nano bubbles.

9. The method for generating multi-cavity parallel micro-swirling micro-nano bubbles according to claim 8, characterized in that: In step S1, the injection pressure of the liquid entering the liquid distribution chamber is not less than 0.2 MPa, and the gas pressure is at least 0.1 MPa higher than the liquid pressure.

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