A micro bubble generating device based on cylindrical turbulence shearing effect

Abstract

The invention discloses a micro-bubble generating device based on the cylindrical turbulent shearing effect, comprising a circulation pump, a bubble generating device and a pipeline, wherein a water storage system is sequentially connected with the circulation pump and the bubble generating device through the pipeline to form a loop; the bubble generating device comprises a front diffusion section, a rectifying section, a contraction section, a bubble generating section and a rear contraction section which are sequentially connected, a plurality of groups of thin tubes are symmetrically arranged in the bubble generating section, one end of the thin tubes is arranged inside the bubble generating section, and the other end extends to the outside of the bubble generating section, the pipe openings of each group of thin tubes arranged inside the bubble generating section are arranged relatively, and a bubble breaker is arranged at the end of the thin tube inside the bubble generating section, the invention utilizes the high-intensity turbulent pulsation and vortex shearing effect of the back wake area downstream of the cylindrical thin tube wake, and the bubbles are rapidly broken into a series of atomized broken bubbles after contacting with the water flow, so that micro-level or even nano-level micro-bubbles are efficiently, massively and safely generated.

Description

Technical Field

[0001] The invention belongs to the technical field of bubble generation, and in particular relates to a micro bubble generating device based on cylindrical turbulence shearing effect. Background Art

[0002] In recent years, serious water pollution has occurred in various regions of my country, and low dissolved oxygen in the water has led to the death of a large number of fish and aquatic animals. The state and local governments attach great importance to water issues. Local governments have raised the "five water governance" to the national strategic level. The protection and recycling of water resources is of great significance to promoting human health and environmental protection.

[0003] Microbubbles are characterized by small size, large specific surface area, high adsorption rate, long residence time in water, and physical and chemical properties that conventional sized bubbles do not have. Since such bubbles can fully dissolve in the liquid phase, they can effectively promote the interaction and mass transfer process between gas and liquid. Their application has attracted much attention and has a good application prospect in the fields of water conservancy, chemical industry, energy and environment.

[0004] In nature and various engineering applications, the key to solving problems is to generate microbubbles in large quantities and efficiently. High-intensity turbulence disturbance and shearing can fully break large bubbles to form numerous microbubbles. Compared with the traditional stirring tank to break large bubbles, the microbubble generation device using cylindrical turbulence shearing effect is simple, with low operation and maintenance costs, good economic benefits and a wide range of applications. At the moment of microbubble breaking, due to the drastic change of the disappearance of the gas-liquid interface, the high-concentration ions gathered on the interface will instantly release the stored chemical energy, which can stimulate the generation of a large number of hydroxyl free radicals. Hydroxyl free radicals have an ultra-high redox potential and can purify water quality. At the same time, a large number of microbubbles dissolved in water can significantly increase the dissolved oxygen content in rivers, lakes, reservoirs and oceans, promote the growth of aerobic organisms in water, accelerate the degradation of garbage deposited in water, and avoid the death of fish and aquatic animals due to too low dissolved oxygen. Summary of the invention

[0005] In view of the shortcomings and defects of the prior art, the present invention proposes a micro-bubble generating device based on the cylindrical turbulence shear effect, aiming to generate micro-bubbles efficiently, in large quantities and safely, and to improve the wastewater treatment, mineral flotation and aquaculture effects of micro-bubbles.

[0006] In order to solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A micro bubble generating device based on the cylindrical turbulence shearing effect comprises a circulation pump, a bubble generating device and a pipeline, wherein a water storage system is sequentially connected with the circulation pump and the bubble generating device through the pipeline to form a loop; the bubble generating device comprises a front diffusion section, a rectifying section, a contraction section, a bubble generating section and a rear contraction section which are sequentially connected, the bubble generating section is symmetrically provided with a plurality of groups of thin tubes, one end of the thin tubes is placed inside the bubble generating section, and the other end extends to the outside of the bubble generating section, the tube openings of each group of thin tubes placed inside the bubble generating section are arranged oppositely, and a bubble breaker is provided at the end of the thin tube inside the bubble generating section, and a valve is provided on the thin tube outside the bubble generating section; a rectifier is provided in the rectifying section;

[0008] Furthermore, the capillary tube is a cylindrical copper tube;

[0009] Furthermore, the bubble breaker is distributed in a horizontal and vertical array of transverse plates to form parallel channels in the horizontal direction, and the cross-sectional area of ​​each channel is the same; the length of the bubble breaker is 1 / 2 of the length of the capillary inserted into the bubble generating section;

[0010] Furthermore, the rectifier is composed of a plurality of small pipes of equal cross-section arranged in parallel, and the small pipes are fixed by a damping net. The cross-sectional shape of the small pipes can be square, circular or hexagonal, and the rectifier can improve the uniformity of the water flow velocity distribution in the bubble generating section;

[0011] Furthermore, the bubble generating device may also be equipped with a dissolved oxygen detector for monitoring bubble parameters in the water storage system;

[0012] Furthermore, the bubble generating device may also be equipped with a stirrer to better disperse the generated microbubbles in the water environment;

[0013] Furthermore, a flow meter is provided in the pipeline for real-time monitoring of the flow rate of the liquid in the pipeline.

[0014] Beneficial effects of the present invention:

[0015] 1. The rectifier in the rectifier section of the present invention can make the water flow velocity in the bubble generating section uniformly distributed;

[0016] 2. The present invention accelerates the water flow uniformly, reduces flow noise and saves energy consumption by designing the contraction section;

[0017] 3. The bubble generating section of the present invention allows gas to enter the system and interact with water flow through two inserted straight tubes. A bubble breaker is arranged at the tube mouth to reduce the initial size of the bubbles and realize the first stage of breaking. The device is simple, easy to process and has obvious effect. Under the high-intensity turbulent disturbance and shearing action of the cylindrical wake, the bubbles are broken in the second stage to produce the required micron-level or even nano-level bubbles. When the bubbles enter the water storage system, an agitator is arranged to better disperse the bubbles in the ambient water.

[0018] 4. The present invention and the practical device make full use of the high-intensity tail flow generated when the liquid passes through the cylinder, and the bubble generation efficiency is high, pollution-free, and energy-saving; in addition, the flow meter, valve, and circulation pump are all mature products, the entire device is simple in design, easy to install, and has low operating and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall device structure of the present invention;

[0020] Figure 2 It is a structural schematic diagram of the bubble generating device of the present invention;

[0021] Figure 3 It is a schematic diagram of the bubble generating section of the present invention;

[0022] Figure 4 is a schematic cross-sectional view of a bubble breaker of the present invention;

[0023] Figure 5 is a cross-sectional schematic diagram of a rectifier of the present invention;

[0024] Figure 6 It is a transparent organic glass schematic diagram of the bubble generating section of the present invention;

[0025] Figure 7 7(a) is a bubble collection result diagram under low water flow rate conditions, and 7(b) is a bubble collection result diagram under high water flow rate conditions;

[0026] Figure 8 is an evolution diagram of bubble equivalent diameter and detachment period with water flow velocity according to an embodiment of the present invention;

[0027] In the figure, 1. circulation pump, 2. front diffusion section, 3. rectification section, 4. contraction section, 5. valve A, 6. vent, 7. capillary tube, 8. bubble generating section, 9. rear contraction section, 10. flow meter, 11. valve B, 12. pipeline, 13. valve C, 14. microbubble, 15. dissolved oxygen monitor, 16. agitator, 17. bubble breaker, 18. rectifier, 19. damping net. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0029] like Figure 1 As shown in FIG. 1 , a micro-bubble generating device based on the cylindrical turbulent shearing effect is provided with valves C13 and B11 at the water inlet and outlet where the pipeline is connected to the water storage system. The water flow velocity in the main pipeline can be controlled by adjusting the opening of the pipeline valve; Figure 2 As shown, the bubble generating device includes a front diffuser 2, a rectifying section 3, a contraction section 4, a bubble generating section 8 and a rear contraction section 9 which are connected in sequence by flanges. The front diffuser 2 is a gradual flow channel, and the water inlet pipeline and the rectifying section 3 are connected by flanges to achieve a smooth transition between the pipeline and the rectifying section 3. When the liquid passes through the front diffuser 2 and enters the rectifying section 3, the velocity distribution on the axial cross section is uneven, such as Figure 5 A rectifier 18 is provided in the rectifying section 3. The rectifier 18 is composed of many small pipes with square, circular or hexagonal cross-sections arranged in parallel, and the small pipes are fixed by a damping net 19, which divides the large-scale vortex that may exist in the original large flow channel into small-scale vortices. The small-scale vortex has a faster decay rate, which will accelerate the decay of the vortex in the water flow, which is very beneficial to the stability of the downstream water flow and the reduction of turbulence, thereby playing a role in attenuating the vortex and reducing the turbulence; the other end of the rectifying section 3 is connected to the contraction section 4, which is a gradual flow channel that can evenly accelerate the water flow, reduce flow noise and save energy consumption; the other end of the contraction section 4 is connected to the bubble generating section 8 through a flange, such as Figure 3 As shown, a plurality of groups of thin tubes 7 are arranged on the outer wall of the bubble generating section 8 and inserted into the bubble generating section 8. One end of the thin tube 7 is placed inside the bubble generating section 8, and the other end extends to the outside of the bubble generating section 8 to form a vent 6. The tube openings of each group of thin tubes 7 placed inside the bubble generating section 8 are arranged opposite to each other, and a bubble breaker 17 is provided at the end of the thin tube 7 inside the bubble generating section 8. Figure 4 As shown, the bubble breaker 17 is distributed in a horizontal and vertical array of horizontal plates, forming parallel channels in the horizontal direction, and the cross-sectional area of ​​each channel is the same; and the length of the bubble breaker 17 is 1 / 2 of the length of the capillary inserted into the bubble generating section 8; a valve 5 is provided on the capillary 7 located outside the bubble generating section 8, and in this embodiment, the capillary 7 is a cylindrical copper tube. A dissolved oxygen detector 15 and a stirrer 16 can also be provided in the water storage system.

[0030] In order to explain the technical solution of the present invention more clearly, the following is further explained in conjunction with the working process of the present invention:

[0031] In the course of work,

[0032] Open valve C13 and valve B11. When the liquid fills the entire circulation loop, start the circulation pump 1. Driven by the circulation pump 1, the liquid in the loop starts to move and will return to the water storage system through the front diffusion section 2, the rectification section 3, the contraction section 4, the bubble generation section 8 and the rear contraction section 9 in sequence.

[0033] At this time, valve A5 on the capillary tube 7 is opened, and gas is introduced into the capillary tube 7 through the vent 6. The gas enters the bubble generating section 8 after passing through the bubble breaker 17 in the capillary tube 7, and bubbles with a smaller initial size are obtained, thus achieving the first stage of breaking. When the bubbles flow along the liquid flow in the pipeline, when the liquid in the capillary tube 7 passes through the cylindrical blunt body, a Karman vortex street phenomenon is formed in the wake of the cylinder. Under the condition of high water flow velocity, due to the strong shearing effect between the water flow and the vent pipe orifice, and the high-intensity turbulent pulsation and vortex shearing effect in the wake area on the back side of the downstream of the vent pipe, the bubbles are quickly broken into a series of atomized broken bubbles after contacting the water flow. At this time, the bubble size reaches the micron level or even the nano level, and the bubbles are broken in the second stage to produce the required micron level or even nano level bubbles. When the bubbles enter the water storage system, the bubbles can be better dispersed in the ambient water by setting an agitator.

[0034] In this embodiment, the bubble generating section 8 is made of transparent organic glass on all four sides, as shown in the schematic diagram of its structure. Figure 6 The parameters used are: water flow velocity range of 0.21m / s and 4.04m / s, ventilation flow rate of 1200mL / h, and the collected results of the embodiment are as follows Figure 7 As shown in the figure, (a) is under low water flow velocity conditions, and (b) is under high water flow velocity conditions. It can be seen that when the water flow velocity is high, the large bubbles are fully broken and present atomized form. As the water flow velocity increases, the turbulence intensity and velocity gradient in the cylindrical wake area increase, and the bubbles gradually migrate downward in the axial direction. The large bubbles break in the large-scale flow structure and strong shear flow to form multiple small bubbles. The bubble size and growth period decrease, and finally form micron-sized small bubbles in the atomized state. Its evolution process is shown in the figure. Figure 8 As shown in the figure, the microbubbles are small in size, and the contact area between the gas and liquid phases per unit volume of liquid is large. The gas can be fully dissolved in the liquid medium, which can effectively promote the transfer of energy and momentum, and its application has attracted much attention.

[0035] The above embodiments are only used to illustrate the design ideas and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The protection scope of the present invention is not limited to the above embodiments. Therefore, any equivalent changes or modifications made based on the principles and design ideas disclosed by the present invention are within the protection scope of the present invention.

Claims

1. A micro bubble generating device based on cylindrical turbulence shearing effect, It is characterized in that The invention comprises a circulation pump (1), a bubble generating device and a pipeline, wherein the water storage system is sequentially connected to the circulation pump (1) and the bubble generating device through the pipeline to form a loop; the bubble generating device comprises a front diffusion section (2), a rectifying section (3), a contraction section (4), a bubble generating section (8) and a rear contraction section (9) which are sequentially connected; the bubble generating section (8) is symmetrically provided with a plurality of groups of thin tubes (7), one end of the thin tubes (7) is placed inside the bubble generating section (8), and the other end extends to the outside of the bubble generating section (8); the pipe openings of each group of thin tubes placed inside the bubble generating section (8) are arranged opposite to each other, and a gas bubble is provided at the end of the thin tubes (7) inside the bubble generating section (8); A bubble breaker (17) is provided, wherein the bubble breaker (17) realizes first-stage shattering; under the high-intensity turbulent disturbance and shearing action of the cylindrical wake, the bubbles are shattered in the second stage; a valve (5) is provided on the capillary tube (7) located outside the bubble generating section (8); a rectifier (18) is provided in the rectifier section (3); the bubble breaker (17) is distributed in a transverse and longitudinal array of transverse plates to form parallel channels in the horizontal direction, and the cross-sectional area of ​​each channel is the same; the length of the bubble breaker (17) is 1 / 2 of the length of the capillary tube inserted into the bubble generating section (8); and the bubble generating device is also equipped with a stirrer (16).

2. A micro-bubble generating device based on cylindrical turbulence shearing effect according to claim 1, It is characterized in that The capillary tube is a cylindrical copper tube.

3. A micro-bubble generating device based on cylindrical turbulence shearing effect according to claim 1, It is characterized in that The rectifier (18) is composed of a plurality of small pipes with equal cross-sections arranged in parallel, and the small pipes are fixed by damping nets (19).

4. A micro-bubble generating device based on cylindrical turbulence shearing effect according to claim 3, It is characterized in that The cross-sectional shape of the small pipe can be square, circular or hexagonal.

5. A micro-bubble generating device based on cylindrical turbulence shearing effect according to claim 1, It is characterized in that The bubble generating device may also be equipped with a dissolved oxygen detector (15).

6. A micro-bubble generating device based on cylindrical turbulence shearing effect according to claim 1, It is characterized in that A flow meter (10) is also provided in the pipeline.

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