Micro-mixing unit, micro-mixer and micro-mixing device

Abstract

The invention belongs to the technical field of micro-mixers, and discloses a micro-mixing unit, a micro-mixer and a micro-mixing device. The micro-mixing unit is used for mixing two or more liquids and comprises a micro-mixing unit inlet section, an inlet arc transition section, a straight channel, an outlet arc transition section, a micro-mixing unit outlet section and a herringbone groove. The micro-mixing units are arranged in series to form the micro-mixer. The same micro-mixers are arranged in parallel to form the micro-mixing device meeting the high-flux requirement. The micro-mixer can effectively solve the problems that a conventional micro-mixer needs long time for achieving an expected mixing effect, the mixing efficiency is low, the reaction efficiency is low, and high-flux mixing and reaction cannot be realized; the method is suitable for the occasions of drug synthesis, clinical diagnosis and detection, controllable synthesis of nano materials, chemical synthesis, micro-plastic degradation, wastewater treatment, micro-electronic cooling and the like, and can realize high-throughput, high-speed and high-efficiency three-transmission one-reaction under a micro scale.

Description

Technical Field

[0001] The present invention belongs to the technical field of micro mixers and relates to a micro mixing unit, a micro mixer and a micro mixing device. Background Art

[0002] Homogeneous flow and mixing are hallmarks of chemical processes, widely encountered in processes such as process intensification, wastewater treatment, and pharmaceutical formulation. For some industrial processes involving reactions, particularly those involving rapid reactions, good mixing is a prerequisite, and mixing performance has a crucial impact on product yield and quality. Furthermore, scenarios such as highly exothermic or endothermic reactions and the synthesis of hazardous chemicals also place high demands on mixing performance. Micromixers utilize microchannels with characteristic dimensions ranging from micrometers to millimeters (1μm to 1mm) to manipulate fluid flow, mass transfer, heat transfer, and chemical reactions. With advantages such as short diffusion distances, high specific surface area, and precise flow control, they have the potential to meet the homogeneous flow and mixing requirements of production. However, the low Reynolds number (<100) within micromixers results in laminar flow and orderly, parallel streamlines, meaning that mass, momentum, and energy transfer in the flow are achieved through intermolecular transfer. This makes the transition from pre-mixed to fully mixed a slow and inefficient process. Therefore, achieving rapid and efficient mixing has become a key challenge for micromixers.

[0003] Since the mixing process within a micromixer primarily relies on molecular diffusion, the primary approach to increasing mixing rates is to further increase the contact area between fluids of varying concentrations and reduce the distance required for diffusion. A wide variety of micromixers have been developed. Depending on whether or not an external power source is present, micromixers can be categorized as active or passive. Active mixers enhance material transport by applying external energy fields, such as electric, magnetic, or acoustic fields. Passive mixers rely on specialized geometric structures to continuously alter the fluid's flow state, achieving efficient mixing by creating chaotic convection. While active micromixers can achieve faster and more uniform material distribution, their high energy consumption and integration difficulties significantly limit their practical application. Passive micromixers, on the other hand, require no additional energy and have a relatively simple structure, making them easier to integrate and scale up in parallel.

[0004] According to the basic principle of enhanced mixing, passive micromixers can be further divided into types such as splitting and recombination, contraction-expansion, curved channel induced secondary flow, and channel wall patterning. A micromixer with only one structural type can often only trigger one enhanced mixing mechanism, which only improves the mixing effect of the mixer to a certain extent, resulting in poor mixing effect of the micromixer and low reaction efficiency of the microreactor, which cannot meet the requirements of process intensification, wastewater treatment, and pharmaceutical preparation for mixing performance. Integrating different structures in a single mixing unit to achieve synergistic effects of different mixing enhancement strategies has greater mixing enhancement potential (Stroock AD, Dertinger SK, Ajdari A. Science, 2002, 295 (5555), 647-651; Liao Y, Mechulam Y, Lassalle-Kaiser B. Scientific Reports, 2021, 11 (1): 20119; Rhoades T, Kothapalli CR, Fodor P S. Micromachines, 2020, 11 (1): 61). Therefore, it is necessary to propose new micro-mixing units, micro-mixers and micro-mixing devices based on the above innovative ideas. Summary of the Invention

[0005] The purpose of this patent is to provide a micro-mixing unit, based on which a micro-mixer and a micro-mixing device are constructed to solve the problems existing in the above-mentioned prior art. This micro-mixer can effectively overcome the problems of conventional micro-mixers, such as the long time required to achieve the desired mixing effect, low mixing efficiency, low reaction efficiency, and the inability to achieve high-throughput mixing and reaction. It is suitable for drug synthesis, clinical diagnosis and detection, controlled synthesis of nanomaterials, chemical synthesis, microplastic degradation, wastewater treatment, microelectronics cooling and other occasions, and can achieve high-throughput, high-speed and high-efficiency three-transmission and one-reaction at a microscale.

[0006] The technical solution of the present invention:

[0007] A micro-mixing unit, a micro-mixer and a micro-mixing device, comprising:

[0008] The micro-mixing unit is used for mixing two or more liquids, including a micro-mixing unit inlet section, an inlet arc transition section, a straight channel, an outlet arc transition section, a micro-mixing unit outlet section and a herringbone groove; from left to right, they are the micro-mixing unit inlet section, the inlet arc transition section, the straight channel, the outlet arc transition section and the micro-mixing unit outlet section, and the herringbone groove is arranged on the upper wall or the lower wall of the micro-mixing unit; wherein, the micro-mixing unit inlet section is a short straight rectangular tube; the inlet arc transition section is composed of a fan-shaped arc surface, and the fan-shaped arc surface is divided into a large fan surface and a small fan surface by the micro-mixing unit inlet section, The corresponding parts are the large sector of the inlet arc transition section and the small sector of the inlet arc transition section; the cross section of the straight channel is rectangular; the outlet arc transition section is composed of a sector-shaped arc surface, which is divided into a large sector and a small sector by the outlet section of the micro-mixing unit, corresponding to the large sector of the outlet arc transition section and the small sector of the outlet arc transition section; the inlet arc transition section, the straight channel and the outlet arc transition section constitute the fluid flow channel of the micro-mixing unit; the outlet section of the micro-mixing unit is a short straight rectangular tube; the herringbone groove is a rectangular groove in the shape of a herringbone, with one side being the long side and the other side being the short side; the length L of the micro-mixing unit is unit is the distance between the inlet section and the outlet section of the micro-mixing unit, and the width w of the micro-mixing unit E is the width of the straight channel;

[0009] Preferably, the rectangular cross-sections of the micro-mixing unit inlet section and the micro-mixing unit outlet section have the same size;

[0010] Preferably, the centers of the inlet arc transition section and the outlet arc transition section are both on the center lines of the micro-mixing unit inlet section and the micro-mixing unit outlet section; the angle α between the large sector of the inlet arc transition section and the large sector of the outlet arc transition section is 90°, and the angle β between the small sector of the inlet arc transition section and the small sector of the outlet arc transition section is 5° to 85°; the radii of the large sector of the inlet arc transition section and the small sector of the outlet arc transition section are equal;

[0011] Preferably, the center line of the inlet section and the outlet section of the micro-mixing unit is used as the reference line, and the left and right positions of the reference line are swapped to form a new mixing unit; the mixing capacity of the micro-mixing unit before and after the swap is unchanged;

[0012] Preferably, the width w of the straight channel E The ratio of the radius r of the inlet arc transition section (or the radius of the outlet arc transition section) is (1.087-1.996):1;

[0013] Preferably, the long side of the herringbone groove is located on the same side as the large sector of the inlet arc transition section and the large sector of the outlet arc transition section, and the short side of the herringbone groove is located on the same side as the small sector of the inlet arc transition section and the small sector of the outlet arc transition section;

[0014] Preferably, the angle between the long side of the herringbone groove and the centerline of the micro-mixing unit inlet section and the micro-mixing unit outlet section, and the angle between the short side of the herringbone groove and the centerline of the micro-mixing unit inlet section and the micro-mixing unit outlet section, are equal and within the range of 30° to 80°; the depth d of the herringbone groove refers to the depth of the groove arranged on the upper wall or the lower wall, the depth h of the micro-mixing unit refers to the distance between the upper wall and the lower wall, and the ratio of the depth d of the herringbone groove to the depth h of the micro-mixing unit is 0.1 to 2; the width a of the herringbone groove refers to the width of the groove in the direction of the centerline of the micro-mixing unit inlet section and the micro-mixing unit outlet section, and the spacing b of the herringbone groove refers to the width between adjacent grooves in the direction of the centerline of the micro-mixing unit inlet section and the micro-mixing unit outlet section, and the ratio of the width a of the herringbone groove to the spacing b of the herringbone groove is 1 to 15;

[0015] Preferably, the herringbone groove is arranged on the upper wall surface of the micro-mixing unit flow channel and also on the lower wall surface of the micro-mixing unit flow channel;

[0016] Preferably, the micro-mixing units are arranged and combined to form four micro-mixing units with different spatial arrangements, namely, micro-mixing unit A, micro-mixing unit B, micro-mixing unit C, and micro-mixing unit D, according to the positions of the large sector of the inlet circular arc transition section, the small sector of the inlet circular arc transition section, the large sector of the outlet circular arc transition section, and the small sector of the outlet circular arc transition section, as well as the arrangement positions of the herringbone grooves on the upper wall surface and the lower wall surface.

[0017] The present invention provides a micromixer for mixing two or more liquids, and the micromixer is formed by arranging the above four micromixing units with different spatial structures in series;

[0018] Preferably, any one micro-mixing unit is arranged in series to form a micro-mixer, which can be called a micro-mixer of a single mixing unit;

[0019] Preferably, two kinds of micro-mixing units are selected and the mixing units appear alternately (for example, ABAB type, AABB type or AAABBB type, etc.) to form a micro-mixer, which can be called a micro-mixer with alternating mixing units;

[0020] The present invention provides a micro-mixing device for mixing two or more liquids. By arranging the same micro-mixers in parallel, a micro-mixing device that meets high throughput requirements is formed.

[0021] Preferably, the fluid input and output channels of the micro-mixing device are both designed as dendritic fractal channels.

[0022] Beneficial effects of the present invention:

[0023] (1) The micro-mixing unit includes a sudden expansion section (at the inlet section of the micro-mixing unit) and a sudden contraction section (at the outlet section of the micro-mixing unit). Compared with the general contraction-expansion structure, the sudden expansion-contraction structure can, on the one hand, generate a larger reverse pressure gradient and reduce the proportion of the contraction part of the channel, thereby reducing the flow pressure drop of the channel; on the other hand, the upper and lower wall areas of the micro-mixing unit are large, which can increase the exposure of the catalyst in the scenario where the catalyst needs to be arranged on the upper and lower walls of the microchannel, and can increase the heat transfer area in the scenario where heat needs to be transferred through the wall.

[0024] (2) The micro-mixing unit includes an inlet arc transition section and an outlet arc transition section. The arc transition is used to avoid the occurrence of dead zones and to make the flow between the inlet and outlet of the micro-mixing unit and the straight channel smoother.

[0025] (3) The large and small sectors of the arc transition section at the inlet of the micro-mixing unit are asymmetrically arranged on both sides of the center line of the inlet and outlet sections of the micro-mixing unit, which can form horizontal vortices; the herringbone grooves arranged on the upper or lower wall can form vertical vortices within the channel cross section. The synergistic effect of the two can further enhance the mixing effect.

[0026] (4) The micromixer is composed of micromixing units connected in series, with a simple arrangement. The micromixing units have diverse structures and consistent mixing effects. Through different series combinations, micromixers with different mixing performances can be formed, which are suitable for different application scenarios.

[0027] (5) The micro-mixing device is composed of the same micro-mixers connected in parallel. Drawing on the transmission mechanism of plant roots in natural systems, the input and output channels of the fluid are designed as dendritic fractal channels. This device can make the fluid enter each micro-mixer more evenly and has the characteristics of simple amplification. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 1 is a front view and a top view of a micro-hybrid unit (micro-hybrid unit A);

[0029] Figure 2 is a three-dimensional diagram of the micro-hybrid unit A;

[0030] Figure 3 is a three-dimensional diagram of the micro-hybrid unit B;

[0031] Figure 4 is a three-dimensional diagram of the micro-hybrid unit C;

[0032] Figure 5 is a three-dimensional diagram of the micro-hybrid unit D;

[0033] Figure 6A micromixer with alternating mixing units (AACC type) formed by alternating micromixing units A and C arranged in series.

[0034] Figure 7 is a schematic diagram of a micro-mixing device formed by micro-mixers arranged in parallel;

[0035] In the figure: 1 micro-mixing unit, 2 micro-mixing unit inlet section, 3 inlet arc transition section, large sector of inlet arc transition section 301, small sector of inlet arc transition section 302, 4 straight channel, 5 outlet arc transition section, large sector of outlet arc transition section 501, small sector of outlet arc transition section 502, 6 micro-mixing unit outlet section, 7 herringbone groove, 701 long side, 702 short side, 8 upper wall, 9 lower wall, 10 micro-mixing unit A, 11 micro-mixing unit B, 12 micro-mixing unit C, 13 micro-mixing unit D. DETAILED DESCRIPTION

[0036] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and technical solutions.

[0037] See also Figures 1 to 7 , the present invention provides the following solutions:

[0038] A micro-mixing unit, the micro-mixing unit 1 includes a micro-mixing unit inlet section 2, an inlet arc transition section 3, a straight channel 4, an outlet arc transition section 5, a micro-mixing unit outlet section 6 and a herringbone groove 7; from left to right are the micro-mixing unit inlet section 2, the inlet arc transition section 3, the straight channel 4, the outlet arc transition section 5 and the micro-mixing unit outlet section 6, the herringbone groove 7 is distributed on the lower wall surface 9 of the micro-mixing unit; the micro-mixing unit inlet section 2 is a short straight rectangular tube; the inlet arc transition section 3 is composed of a sector-shaped arc surface, which is divided into two sectors, large and small, by the micro-mixing unit inlet section, including the inlet arc transition section The large sector 301 and the small sector 302 of the inlet circular arc transition section; the cross-section of the straight channel 4 is rectangular; the outlet circular arc transition section 5 is composed of a sector-shaped circular arc surface, and the sector-shaped circular arc surface is divided into two large and small sectors by the micro-mixing unit outlet section, including a large sector 501 of the outlet circular arc transition section and a small sector 502 of the outlet circular arc transition section; the inlet circular arc transition section 3, the straight channel 4 and the outlet circular arc transition section 5 constitute the fluid flow channel of the micro-mixing unit; the mixing unit outlet section 5 is a short straight rectangular tube; the herringbone groove 7 is a rectangular groove in a herringbone shape, with one side being a long side 701 and the other side being a short side 702;

[0039] Furthermore, the rectangular cross-sections of the micro-mixing unit inlet section 2 and the micro-mixing unit outlet section 6 have a width of 50 μm and a height of 70 μm;

[0040] Furthermore, the centers of the inlet arc transition section 3 and the outlet arc transition section 5 are both on the center lines of the micro-mixing unit inlet section 2 and the micro-mixing unit outlet section 6; the angle α of the large sectors 301 and 501 of the inlet arc transition section 3 and the outlet arc transition section 5 is 90°, and the angle β of the small sectors 302 and 502 is 25.4°; the large sector radius and the small sector radius of the inlet arc transition section and the outlet arc transition section are equal;

[0041] Furthermore, the width w of the straight channel 4 E The ratio of the radius r of the sector of the inlet arc transition section 3 (or the radius r of the sector of the outlet arc transition section 5) is 1.429:1;

[0042] Furthermore, the long side of the herringbone groove is on the same side as the large sector of the inlet arc transition section and the outlet arc transition section, and the short side of the herringbone groove is on the same side as the small sector of the inlet arc transition section and the outlet arc transition section;

[0043] Furthermore, the angles between the long side 701 and the short side 702 of the herringbone groove 7 and the center lines of the micro-mixing unit inlet section 2 and the micro-mixing unit outlet section 6 are both 45°, the ratio of the depth d of the herringbone groove 7 to the depth h of the micro-mixing unit 1 is 0.5, and the ratio of the width a of the herringbone groove 7 to the spacing b of the herringbone groove 7 is 2.7;

[0044] Furthermore, the herringbone groove 7 is arranged on the upper wall surface 8 of the micro-mixing unit flow channel (see Figure 4 and Figure 5 ), can also be arranged on the lower wall surface 9 of the micro-mixing unit flow channel (see Figure 2 and Figure 3 );

[0045] Furthermore, the micro-mixing unit can be formed into a micro-mixing unit A10 (see Figure 2 ), micro-hybrid unit B11 (see Figure 3 ), micro-mixing unit C12 (see Figure 4 ) and micro-hybrid unit D13 (see Figure 5 );

[0046] A micromixer is formed by arranging a micromixing unit A10 and a micromixing unit C12 in series;

[0047] Furthermore, the micro-mixing unit A10 and the micro-mixing unit C12 are selected, and the mixing units appear alternately in pairs to form an AACC type micro-mixer (see Figure 6 );

[0048] A micro-mixing device is formed by arranging CCAA type micro-mixers in parallel to meet the high-throughput requirements (see Figure 7 );

[0049] Furthermore, the fluid input and output channels of the micro-mixing device are both designed as dendritic fractal channels.

[0050] Working Principle: Two liquids pass through a dendritic fractal channel and, after multiple diversions, enter a micromixer comprised of multiple micromixing units. The liquids to be mixed enter the micromixing unit 1 through the micromixing unit inlet section 2. The mixed liquid flows within the inlet arc transition section 3. The use of an arc transition effectively avoids the occurrence of flow dead zones, making the flow between the micromixing unit inlet section 2 and the straight channel 4 smoother. The mixed liquid flowing through the straight channel 4 enters the outlet arc transition section 5 and ultimately leaves the micromixing unit 1 through the micromixing unit outlet section 6. The outlet arc transition section 5 also has an arc transition structure, which can avoid the existence of flow dead zones. Because a sudden expansion structure is formed between the micro-mixing unit inlet section 2 and the subsequent inlet arc transition section 3 and straight channel 4, and a sudden contraction structure is formed between the outlet arc transition section 3 and straight channel 5 and the micro-mixing unit outlet section 6, a larger reverse pressure gradient can be generated and the proportion of the channel contraction portion can be reduced to reduce the flow pressure drop in the channel; it can also ensure that the area of the upper wall 8 and lower wall 9 of the micro-mixing unit 1 is larger, increasing the exposure of the catalyst or increasing the heat transfer area. The herringbone grooves 7 arranged on the upper wall 8 or lower wall 9 can form vertical vortices within the channel cross section; the large fan 301 and small fan 302 of the inlet arc transition section of the micro-mixing unit 1 are asymmetrically arranged on both sides of the center line of the micro-mixing unit inlet section 2 and the micro-mixing unit outlet section 6, which can form horizontal vortices; the synergistic effect of the two can improve the mixing effect.

[0051] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A micro-mixing unit, characterized in that: The micro-mixing unit is used for mixing two or more liquids, and includes a micro-mixing unit inlet section, an inlet arc transition section, a straight channel, an outlet arc transition section, a micro-mixing unit outlet section and a herringbone groove; from left to right, they are the micro-mixing unit inlet section, the inlet arc transition section, the straight channel, the outlet arc transition section and the micro-mixing unit outlet section, and the herringbone groove is arranged on the upper wall or the lower wall of the micro-mixing unit; wherein, the micro-mixing unit inlet section is a short straight rectangular tube; the inlet arc transition section is composed of a sector-shaped arc surface, and the sector-shaped arc surface is divided into a large sector by the micro-mixing unit inlet section. and small fan-shaped surfaces, corresponding to the large fan-shaped surface of the inlet circular arc transition section and the small fan-shaped surface of the inlet circular arc transition section; the cross-section of the straight channel is rectangular; the outlet circular arc transition section is composed of a fan-shaped arc surface, and the fan-shaped arc surface is divided into a large fan-shaped surface and a small fan-shaped surface by the micro-mixing unit outlet section, corresponding to the large fan-shaped surface of the outlet circular arc transition section and the small fan-shaped surface of the outlet circular arc transition section; the inlet circular arc transition section, the straight channel and the outlet circular arc transition section constitute the fluid flow channel of the micro-mixing unit; the outlet section of the micro-mixing unit is a short straight rectangular tube; the herringbone groove is a rectangular groove in a herringbone shape, with one side being the long side and the other side being the short side.

2. The micro-mixing unit, micro-mixer and micro-mixing device according to claim 1, characterized in that: The rectangular cross-sections of the micro-mixing unit inlet section and the micro-mixing unit outlet section have the same size.

3. The micro-mixing unit, micro-mixer and micro-mixing device according to claim 1, characterized in that: The centers of the inlet arc transition section and the outlet arc transition section are both on the center lines of the micro-mixing unit inlet section and the micro-mixing unit outlet section; the angle α between the large sector of the inlet arc transition section and the large sector of the outlet arc transition section is 90°, and the angle β between the small sector of the inlet arc transition section and the small sector of the outlet arc transition section is 5° to 85°; the radii of the large sector of the inlet arc transition section and the small sector of the outlet arc transition section are equal; Taking the center line of the micro-mixing unit inlet section and the micro-mixing unit outlet section as the reference line, the left and right positions of the reference line are swapped to form a new mixing unit.

4. The micro-mixing unit, micro-mixer and micro-mixing device according to claim 1, characterized in that: Width of straight channel w E The ratio of the radius r of the sector of the arc transition section at the entrance is (1.087~1.996):

1.

5. The micro-mixing unit, micro-mixer and micro-mixing device according to claim 1, characterized in that: The long side of the herringbone groove is located on the same side as the large sector surface of the inlet arc transition section and the large sector surface of the outlet arc transition section, and the short side of the herringbone groove is located on the same side as the small sector surface of the inlet arc transition section and the small sector surface of the outlet arc transition section; The angles between the long side of the herringbone groove and the center lines of the micro-mixing unit inlet section and the micro-mixing unit outlet section, as well as the angles between the short side of the herringbone groove and the center lines of the micro-mixing unit inlet section and the micro-mixing unit outlet section, are equal and within the range of 30° to 80°; the ratio of the depth d of the herringbone groove to the depth h of the micro-mixing unit is 0.1 to 2; and the ratio of the width a of the herringbone groove to the spacing b of the herringbone groove is 1 to 15; The herringbone grooves are arranged on the upper wall surface of the micro-mixing unit circulation channel and also on the lower wall surface of the micro-mixing unit circulation channel.

6. The micro-mixing unit, micro-mixer and micro-mixing device according to claim 1, characterized in that: The micro-mixing units are arranged and combined to form four micro-mixing units with different spatial arrangements, namely, micro-mixing unit A, micro-mixing unit B, micro-mixing unit C, and micro-mixing unit D, based on the positions of the large sector of the inlet circular arc transition section, the small sector of the inlet circular arc transition section, the large sector of the outlet circular arc transition section, and the small sector of the outlet circular arc transition section, as well as the arrangement positions of the herringbone grooves on the upper and lower walls.

7. A micro mixer, characterized in that: The micromixer is used for mixing two or more liquids, and is formed by arranging the four micromixing units of the spatial arrangement structure according to claim 6 in series.

8. The micro mixer according to claim 7, characterized in that The four micro-mixing units in a spatial arrangement structure are arranged in series to form a micro-mixer, which is a micro-mixer of a single mixing unit.

9. The micro mixer according to claim 7, characterized in that The four spatially arranged micro-mixing units are any two micro-mixing units arranged in series to form a micro-mixer. The micro-mixing units appear alternately, forming a micro-mixer of alternating mixing units.

10. A micro-mixing device, characterized in that: A micro-mixing device for mixing two or more liquids is formed by arranging the micro-mixers described in any one of claims 7 to 9 in parallel to meet high-throughput requirements; the input and output channels of the fluid in the micro-mixing device are both designed as dendritic fractal channels.

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