Micro-channel structure for homogeneous mixing

Abstract

The utility model relates to the technical field of fluid mixing and reaction strengthening structures, and discloses a micro-channel structure for homogeneous mixing, which comprises a central micro-channel, the central micro-channel is spiral, the starting point of the central micro-channel is provided with a liquid outlet, the end point of the central micro-channel is provided with at least two liquid inlets, and the liquid inlets are communicated with the central micro-channel. A plurality of forward Tesla valve structures are communicated with the inner side and the outer side of the central micro-channel in a staggered manner, and the forward Tesla valve structures are arranged on the central micro-channel in a staggered manner, so that secondary flow named Dean vortex can be generated in the spiral central micro-channel; according to the fluid mixing device, fluid is mixed through the spiral flow channel, the mixing effect is achieved, the Tesla valve structure can divide the fluid into two strands and collide with each other, the mixing effect is achieved, meanwhile, the collision effect of the Tesla valve structure and the Dean vortex effect of the spiral flow channel are utilized, and the collision effect and the Dean vortex effect cooperate with each other, so that a flow field becomes more disordered, and the mutual contact and mixing probability of the fluid is increased.

Description

Technical Field

[0001] This invention relates to the field of fluid mixing and reaction enhancement structure technology, and in particular to a microchannel structure for homogeneous mixing. Background Technology

[0002] Microreactors are reaction devices characterized by their micrometer-scale feature size (typically ranging from 5 μm to 2 mm). Their core structure includes a precisely designed network of microfluidic channels, and they have become important reaction engineering systems in fields such as chemical synthesis, bioengineering, and pharmaceutical research. Compared to traditional macroscopic reaction equipment, these miniaturized devices, with their significantly improved specific surface area, low reagent consumption, and rapid reaction kinetics, have become a hot topic in interdisciplinary research and are gradually achieving industrial application.

[0003] However, the fluid within microchannels often exhibits a laminar flow state, which is detrimental to mixing and reaction processes. Therefore, microchannel structures need to be specially designed to enhance mixing and reaction effects. Currently, various passive microreactors have been developed both domestically and internationally to optimize the mixing process. For example, a secondary flow called a Dean vortex is generated in a spiral microchannel, which can enhance mixing. However, to achieve completely uniform mixing, a relatively long spiral channel is usually required, thus increasing space occupancy. The Tesla valve, as a classic two-dimensional planar flow structure, has the characteristics of unidirectional flow and enhanced mixing. Currently, there are also applications of Tesla valve structures in microchannel structures. For example, Chinese patent CN117123077A uses a Tesla valve structure and a bent channel for mixing. The mixing principle of both the bent channel and the Tesla valve is to cause the fluids to collide with each other. However, the bent channel generates significant kinetic energy loss at the corners, thus increasing energy consumption. Utility Model Content

[0004] To address the aforementioned technical problems, this invention provides a microchannel structure for homogeneous mixing, which enables more thorough liquid mixing and shortens the channel length, thereby reducing space occupancy.

[0005] This invention provides a microchannel structure for homogeneous mixing, including a central microchannel, which is spiral in shape. The central microchannel has an outlet at its starting point and an inlet at its ending point. There are at least two inlets. Multiple positive Tesla valve structures are interleaved and connected on the inner and outer sides of the central microchannel.

[0006] Optionally, the cross-sectional branch height of the Tesla valve structure is 1 to 10 times the diameter of the central microchannel.

[0007] Optionally, the angle θ between the inlet of the Tesla valve structure and the central microchannel is greater than 20° and less than 120°.

[0008] Optionally, the angle β between the outlet of the Tesla valve structure and the central microchannel is greater than 30° and less than 90°.

[0009] Optionally, the cross-section of the central microchannel can be circular, square, elliptical, or triangular.

[0010] Optionally, the cross-section of the central microchannel is circular, with a diameter of 0.001 mm to 10 mm.

[0011] Optionally, the two inlets can be arranged in a Y-shape, T-shape, or U-shape.

[0012] Optionally, the central microchannel is 7.34 meters long and has 13 Tesla valve structures.

[0013] The technical solution provided by this utility model has the following advantages compared with the prior art:

[0014] This invention provides a microchannel structure for homogeneous mixing. By staggering forward Tesla valve structures on a central spiral microchannel, the spiral microchannel generates a secondary flow called a Dean vortex, producing a mixing effect. The Tesla valve structures divide the fluid into two streams that collide, further enhancing the mixing effect. The collision effect of the Tesla valves and the Dean vortex effect of the spiral channel work synergistically to create a more chaotic flow field, increasing the probability of fluid contact and mixing, thus further enhancing the mixing effect. The spiral central microchannel has a smooth curve, preventing sudden kinetic energy loss and increased energy consumption. Due to the superior mixing effect of this microchannel structure for homogeneous mixing, compared to ordinary spiral channels, the channel length can be shortened, thereby reducing space occupancy. Attached Figure Description

[0015] Figure 1 A schematic diagram of a microchannel structure for homogeneous mixing provided in an embodiment of this utility model;

[0016] Figure 2 A partial structural schematic diagram of a microchannel structure for homogeneous mixing provided in an embodiment of this utility model;

[0017] Figure 3 A schematic diagram of a Dean vortex in a typical spiral channel;

[0018] Figure 4 Hybrid simulation diagram of the central microchannel-Tesla valve structure provided for embodiments of this utility model;

[0019] Figure 5Concentration distribution diagrams at the outlet of the central microchannel-Tesla valve structure and the ordinary spiral channel in the hybrid simulation provided for embodiments of this utility model.

[0020] Explanation of reference numerals in the attached figures:

[0021] 1. Liquid inlet; 2. Liquid outlet; 3. Tesla valve structure; 4. Central microchannel. Detailed Implementation

[0022] The following describes a specific embodiment of the present invention in detail with reference to the accompanying drawings. However, it should be understood that the scope of protection of the present invention is not limited to the specific embodiment.

[0023] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the technical solution of this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0024] Currently, various passive microreactors have been developed both domestically and internationally to optimize the mixing process. For example, a secondary flow called Dean's vortex is generated in a spiral microchannel, which can enhance mixing. However, to achieve completely uniform mixing, a long spiral channel is usually required, which increases the space occupancy rate. The Tesla valve, as a classic two-dimensional planar flow structure, has the characteristics of unidirectional flow and enhanced mixing. Currently, there are also Tesla valve structures introduced into microchannel structures. For example, Chinese patent with publication number CN117123077A uses a Tesla valve structure and a bent channel for mixing. The mixing principle of both the bent channel and the Tesla valve is to make the fluids collide with each other. However, the bent channel will generate a large kinetic energy loss at the corner, thus increasing energy consumption.

[0025] Therefore, this utility model provides a microchannel structure for homogeneous mixing, which enables more thorough mixing of liquids and shortens the channel length, thereby reducing space occupancy.

[0026] At least one embodiment of this utility model provides a microchannel structure for homogeneous mixing, including a central microchannel, which is spiral in shape. The central microchannel has an outlet at its starting point and an inlet at its ending point. There are at least two inlets. Multiple positive Tesla valve structures are alternately connected on the inner and outer sides of the central microchannel.

[0027] In the microchannel structure for homogeneous mixing provided in the above-described embodiment of the present invention, positive Tesla valve structures are arranged alternately on the central microchannel, which is set in a spiral shape. The spiral central microchannel can generate a secondary flow called Dean's vortex inside, producing a mixing effect. The Tesla valve structure can divide the fluid into two streams and make them collide with each other, thereby producing a mixing effect.

[0028] The present invention will be described below through several specific embodiments. To keep the following description of the embodiments of the present invention clear and concise, detailed descriptions of known functions and components may be omitted. When any component of an embodiment of the present invention appears in more than one drawing, the component may be represented by the same reference numerals in each drawing.

[0029] refer to Figure 1 , Figure 1 A schematic diagram of a microchannel structure for homogeneous mixing provided in this embodiment of the present invention is shown below. Figure 1 As shown, this embodiment of the invention provides a microchannel structure for homogeneous mixing, including a central microchannel 4. The central microchannel 4 is spiral-shaped. The spiral design can extend the flow path of the fluid within the microchannel, increase the mixing time and contact area, thereby improving the mixing efficiency. The spiral structure can generate centrifugal force, promoting laminar mixing of different fluids and reducing mixing dead zones. The spiral design achieves a longer flow path within a limited space, making it suitable for miniaturized devices. The starting point of the central microchannel 4 has a liquid outlet 2 for discharging the mixed fluid, which can optimize the fluid outflow velocity and avoid backflow or blockage. The end point of the flow channel 4 has at least two inlets 1 for introducing the fluid to be mixed. This multi-inlet design allows for the simultaneous injection of multiple component fluids, improving mixing efficiency. Multiple forward-facing Tesla valve structures 3 are interconnected on the inner and outer sides of the central microchannel 4. These Tesla valve structures 3 have unidirectional flow characteristics, effectively preventing fluid backflow and ensuring unidirectional flow within the microchannel. The interconnected Tesla valve structures generate eddies and turbulence as fluid passes through, breaking the laminar flow state and promoting the mixing of different fluids. The compact design of the Tesla valve structures 3 makes them suitable for integration within the microchannel without adding extra volume. Microchannel structures typically use biocompatible materials (such as PDMS) or chemically resistant materials (such as glass and silicon) to meet the needs of different applications. Microfabrication technologies such as photolithography, soft photolithography, and 3D printing can be used to ensure the high precision and consistency of the microchannels.

[0030] This invention provides a microchannel structure for homogeneous mixing. By staggering forward Tesla valve structures on a central spiral microchannel, the spiral microchannel generates a secondary flow called a Dean vortex, producing a mixing effect. The Tesla valve structures divide the fluid into two streams that collide, further enhancing the mixing effect. The collision effect of the Tesla valves and the Dean vortex effect of the spiral channel work synergistically to create a more chaotic flow field, increasing the probability of fluid contact and mixing, thus further enhancing the mixing effect. The spiral central microchannel has a smooth curve, preventing sudden kinetic energy loss and increased energy consumption. Due to the superior mixing effect of this microchannel structure for homogeneous mixing, compared to ordinary spiral channels, the channel length can be shortened, thereby reducing space occupancy.

[0031] Optionally, the cross-sectional branch height of the Tesla valve structure 3 is 1 to 10 times the diameter of the central microchannel 4. The cross-sectional branch height of the Tesla valve structure 3 refers to the vertical height of the branch channel in the Tesla valve structure, which is related to the diameter of the central microchannel 4. The diameter of the central microchannel 4 is the reference size in the design and affects the overall flow characteristics. When the cross-sectional branch height of the Tesla valve structure 3 is 1 times the diameter of the central microchannel 4, the branch height is the same as the diameter of the central microchannel, the structure is compact, suitable for space-constrained applications, the resistance of the fluid passing through the branch is small, suitable for mixing low-viscosity fluids, the fluid is mainly laminar, the mixing effect is weak, the pressure loss is small, suitable for low-power applications. When the cross-sectional branch height of the Tesla valve structure 3 is 10 times the diameter of the central microchannel 4, the larger branch height can generate stronger eddies and turbulence, significantly improving the mixing efficiency, suitable for high-viscosity fluids or applications requiring strong mixing, generating strong turbulence and eddies, significantly enhancing the mixing effect, the pressure loss is large, and the pumping power needs to be considered.

[0032] When the cross-sectional branch height of Tesla valve structure 3 is low, the mixing time is long, which is suitable for applications with low requirements for mixing speed. The mixing uniformity is low, which is suitable for preliminary mixing. When the cross-sectional branch height of Tesla valve structure 3 is high, the mixing time is significantly shortened, which is suitable for rapid mixing requirements. The mixing uniformity is high, which is suitable for fine mixing.

[0033] refer to Figure 2 , Figure 2 A partial structural diagram of a microchannel structure for homogeneous mixing is provided for an embodiment of this utility model, as shown below. Figure 2 As shown, the angle θ between the inlet of the Tesla valve structure 3 and the central microchannel 4 is greater than 20° and less than 120°. In addition to the flow diversion, the resistance of the fluid flowing in the forward direction is much smaller than the resistance of the reverse flow.

[0034] Specifically, the angle β between the outlet of the Tesla valve structure 3 and the central microchannel 4 is greater than 30° and less than 90°. This angle provides momentum perpendicular to the main flow direction to the fluid in the branch of the Tesla valve structure 3.

[0035] Optionally, the cross-section of the central microchannel 4 includes one of the following: circular, square, elliptical, or triangular. Different cross-sectional shapes have a significant impact on the fluid dynamics characteristics, manufacturing process, and application scenarios of the microchannel structure. Each shape has different fluid dynamics characteristics, manufacturing process, and application scenarios. Circular shapes are suitable for low power consumption and uniform flow, square and triangular shapes are suitable for strong mixing, and elliptical shapes are in between. Through numerical simulation and experimental verification, the cross-sectional shape can be optimized to meet the needs of different application scenarios. Future development directions include composite cross-sections and adaptive design.

[0036] Circular cross-sections offer the best flow uniformity, with a relatively even velocity distribution within the channel. They also exhibit lower pressure loss, making them suitable for low-power applications. Circular cross-sections are relatively easy to manufacture, making them suitable for various microfabrication techniques (such as photolithography and 3D printing). Square cross-sections tend to generate vortices at the corners, enhancing mixing, but they also have higher pressure loss, making them suitable for applications requiring intense mixing. Square cross-sections are relatively complex to manufacture and require high-precision machining techniques. Elliptical cross-sections fall between circular and square cross-sections, offering some flow uniformity and mixing, with moderate pressure loss, making them suitable for medium-level mixing needs. Elliptical cross-sections are moderately difficult to manufacture and require specific machining techniques. Triangular cross-sections generate strong vortices at the corners, significantly enhancing mixing, but they also have higher pressure loss, making them suitable for applications requiring intense mixing. Triangular cross-sections are complex to manufacture and require high-precision machining techniques.

[0037] The cross-sectional feature size of the central microchannel 4 is 0.001mm to 10mm. The cross-section of the central microchannel 4 is circular, and the diameter of the cross-section is 0.001mm to 10mm. This range covers the scale from micrometer to millimeter and is suitable for a variety of microchannel and microfluidic applications.

[0038] Micrometer-scale cross-sections (0.001mm–0.1mm): In micrometer-scale channels, fluid flow is typically laminar, with mixing primarily relying on diffusion. Micrometer-scale channels have an extremely high surface-to-volume ratio, which is beneficial for heat exchange and chemical reactions. Photolithography is commonly used to fabricate micrometer-scale channels, offering high precision and consistency. Soft photolithography uses elastic materials such as PDMS, making it suitable for biomedical applications. Submillimeter-scale cross-sections (0.1mm–1mm): In submillimeter-scale channels, fluid may exhibit a transitional flow pattern, with mixing effects between laminar and turbulent flow. 3D printing is suitable for medium-scale heat exchange and chemical reactions, and is ideal for rapid prototyping and small-batch production. Precision machining utilizes precision machining technologies such as CNC machine tools. Millimeter-scale cross-sections (1mm–10mm): In millimeter-scale channels, fluid easily forms turbulence, significantly enhancing mixing effects. This is suitable for large-scale heat exchange and chemical reactions. Injection molding is suitable for mass production due to its lower cost. Machining uses traditional machining techniques, making it suitable for high-volume production. Later, computational fluid dynamics (CFD) simulations can be used to optimize channel size and shape, balance mixing efficiency and pressure loss, and verify design parameters by experimentally testing the mixing effect and pressure loss under different sizes.

[0039] Refer again Figure 1 The two liquid inlets 1 are connected in one of three shapes: Y-shaped, T-shaped, or U-shaped. These different connection shapes have an important impact on the fluid mixing effect, flow characteristics, and application scenarios.

[0040] Y-shaped connections can uniformly distribute fluids, making them suitable for mixing processes requiring uniform distribution. At the Y-shaped connection, the fluid convergence generates some turbulence, aiding in initial mixing. This makes them suitable for applications requiring uniform distribution, such as cell culture and drug screening, and for the uniform mixing of low-viscosity reactants. T-shaped connections allow fluids to converge perpendicularly, generating strong turbulence and eddies, significantly enhancing the mixing effect. However, T-shaped connections have a larger pressure loss, making them suitable for applications requiring intense mixing, rapid mixing of high-viscosity reactants, and sample pretreatment requiring efficient mixing. U-shaped connections cause fluid backflow, increasing mixing time and contact area, thus improving mixing efficiency. U-shaped connections have moderate pressure loss, making them suitable for medium-level mixing needs, applications requiring medium shear forces, and the mixing of medium-viscosity reactants. Computational fluid dynamics (CFD) simulations can be used to optimize connection shapes, balancing mixing efficiency and pressure loss. Experimental testing of the mixing effect and pressure loss under different connection shapes can validate the design parameters.

[0041] Specifically, in this embodiment, the length of the central microchannel 4 is 7.34 meters, and the number of Tesla valve structures 3 is 13. Specific Implementation Example 1

[0043] like Figure 1As shown, the microchannel structure for homogeneous mixing provided in this embodiment has two Y-shaped inlets 1, one outlet 2, a Tesla valve structure 3, and a central microchannel 4 with a square cross-section of 10 mm in diameter. The central microchannel 4, which is spiral in shape, contains 13 Tesla valve structures 3. The branch height of the Tesla valve structure 3 is 6 times the diameter of the microchannel. Figure 3 This is a schematic diagram of a Dean vortex in a typical spiral channel. Figure 4 This is a mixing simulation diagram of the central microchannel-Tesla valve structure provided in an embodiment of the present invention. Two liquids flow in from two inlets, one with a concentration of 1 (white in the diagram) and the other with a concentration of 0 (black in the diagram). After mixing, the concentration at the outlet is approximately 0.5 (gray). Figure 5 The concentration distribution diagrams at the outlet of the central microchannel-Tesla valve structure and the ordinary spiral channel in the hybrid simulation provided by this embodiment of the invention are shown. Figure 4 and Figure 5 The concentration values ​​in the figure are normalized concentration values. The closer the concentrations are to each other, the better the mixing effect. In the figure, this is represented by the flatter the lines, the better the mixing effect. It can be seen from the figure that the central microchannel-Tesla valve structure has a better mixing effect than the ordinary spiral channel. Specific Implementation Example 2

[0045] Example 2 has a structure that is basically the same as that of Example 1, except that the cross-section of the central microchannel 4 is a circle with a diameter of 0.005 mm. Specific Implementation Example 3

[0047] Example 3 is basically the same as Example 1 in structure, except that the height of the cross-sectional branch of the Tesla valve structure 3 is 1 times the cross-sectional characteristic dimension of the central microchannel 4. Specific Implementation Example 4

[0049] Example 4 has a structure that is basically the same as that of Example 1, except that there are 4 liquid inlets 1 and a U-shape is formed between adjacent liquid inlets 1.

[0050] The above-described embodiments are merely a few specific examples of this utility model. However, the embodiments of this utility model are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of this utility model.

Claims

1. A microchannel structure for homogeneous mixing, characterized in that, It includes a central microchannel (4), which is spiral in shape. The central microchannel (4) has an outlet (2) at its starting point and an inlet (1) at its ending point. There are at least two inlets (1). Multiple positive Tesla valve structures (3) are interleaved on the inner and outer sides of the central microchannel (4).

2. The microchannel structure for homogeneous mixing as described in claim 1, characterized in that, The cross-sectional branch height of the Tesla valve structure (3) is 1 to 10 times the diameter of the central microchannel (4).

3. The microchannel structure for homogeneous mixing as described in claim 1, characterized in that, The angle θ between the inlet of the Tesla valve structure (3) and the central microchannel (4) is greater than 20° and less than 120°.

4. The microchannel structure for homogeneous mixing as described in claim 1, characterized in that, The angle β between the outlet of the Tesla valve structure (3) and the central microchannel (4) is greater than 30° and less than 90°.

5. The microchannel structure for homogeneous mixing as described in any one of claims 1 to 4, characterized in that, The cross-section of the central microchannel (4) is one of a circle, a square, an ellipse or a triangle.

6. The microchannel structure for homogeneous mixing as described in claim 5, characterized in that, The central microchannel (4) has a circular cross-section with a diameter of 0.001 mm to 10 mm.

7. The microchannel structure for homogeneous mixing as described in claim 1, characterized in that, The two liquid inlets (1) are arranged in a Y-shape, T-shape, or U-shape.

8. The microchannel structure for homogeneous mixing as described in claim 1, characterized in that, The length of the central microchannel (4) is 7.34 meters, and the number of Tesla valve structures (3) is 13.

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