CN115253834B - High-flux passive type rotational flow reinforced micro-mixer - Google Patents

Abstract

A high-flux passive cyclone reinforced micromixer belongs to the technical field of micro-chemical industry. The high-flux passive cyclone reinforced micro-mixer comprises a bottom feed distributor, a middle feed distributor, a mixing cavity, a micro-channel flow dividing element and a mixing cavity upper cover plate. The micro mixer is characterized in that a plurality of flow dividing plates and a plurality of circular plates are stacked in a staggered manner to form a micro-channel flow dividing element, so that the material flows from inside to outside, the speed is gradually reduced, and good initial conditions are provided for the next laminar diffusion; the inner wall surface of the mixing cavity is of a ladder structure so as to avoid fluid attachment and improve the material mixing efficiency; a swirl element is additionally arranged at the discharge port to improve the disturbance of the converged fluid, so that the mixing effect is further enhanced; compared with a mixer in an outside-in flow mode, the invention is not limited by the size of the central tube, can be flexibly designed according to the flow, and has the characteristics of large flux, high efficiency and the like.

Description

A high-throughput passive cyclone-enhanced micromixer

Technical field

The invention belongs to the technical field of microchemical industry, and specifically relates to a high-throughput passive cyclone-enhanced micromixer.

Background technique

Micromixers rely on their unique advantages of efficient mass transfer, heat transfer and small liquid holding capacity to help increase product yields during chemical reactions, reduce the generation of by-products, reduce chemical reaction energy consumption, and make the chemical reaction process green and environmentally friendly. .

At present, micromixers include active micromixers and passive micromixers. Active micromixers mix fluids through external excitation; passive micromixers use various microchannel structures to increase the degree of chaotic flow of fluids and achieve rapid mixing. Purpose. Passive micromixers are widely used due to their simple structure, easy integration, and no need for external power sources. However, the micromixers currently on the market have the following problems:

(1) Conventional Y-type, T-type, snake-type and heart-type microchannel mixers have characteristic sizes between 10-1000 μm, have small flux and are difficult to disassemble and assemble.

(2) In the existing large-flux star-shaped micromixer, the material flows from outside to inside, which causes the material flow rate to increase and the diffusion mixing time to decrease. In addition, the outside-to-in flow mixer is limited by the size of the central tube. When the flow rate further increases, When the diameter of the feed position increases, the size of the central tube increases, but it is difficult to optimize the match between the flow distance from the feed to the central tube and the size of the central tube, which is not conducive to high-throughput quantification; and the outflow fluid has attachments to the surface of the central cone. wall problems, thereby reducing mixing efficiency.

Contents of the invention

In order to overcome the deficiencies in the prior art and improve the above problems, the present invention proposes a high-flux passive cyclone-enhanced micromixer, a high-flux passive cyclone-enhanced micromixer, including sequentially connected bottom feed distributions. device, a middle feed distributor, a mixing chamber, a microchannel splitting element and an upper cover plate of the mixing chamber. The bottom feed distributor includes a bottom feed cavity connected to the A feed pipe, and the middle feed distributor includes a bottom feed cavity connected to the A feed pipe. The middle feed cavity of the feed pipe and the outer periphery of the middle feed cavity on the middle feed distributor are provided with an A material hole that penetrates the middle feed distributor.

The mixing chamber adopts a structure with a plurality of mixing chamber material holes at the bottom and a gradually expanding mixing chamber along the outlet direction. The wall of the mixing chamber is a smooth wall or a stepped wall.

The microchannel flow splitting element is located in the mixing chamber. The microchannel flow splitting element includes a staggered stack of splitter plates and circular plates. The outer circumference of the splitter plate is provided with protrusions. The splitter plate and adjacent circular plates are formed from the inside to the outside. Gradually expanding microchannels are staggered between adjacent splitter plates; the microchannel splitter element composed of splitter plates and circular plates is provided with through-flow splitter element material holes at positions corresponding to the material holes in the mixing chamber.

The upper cover plate of the mixing chamber is connected to the outlet pipe.

In some specific embodiments, the micromixer further includes a swirl element. One end of the swirl element is connected to the microchannel diverter element, and the other end is connected to the upper cover. The swirl element uses a swirl bottom plate with multiple swirl flows. The structure of the blade.

In some specific embodiments, the number of steps on the stepped wall surface is 3-10, the height is 0.5-5mm, and the width is 0.1-5mm.

In some specific implementations, the number of the diverter plates is 10-500, the protrusions on the diverter plates are oval, circular or triangular, the number of protrusions is n, and the staggered angle between adjacent diverter plates is 180/n degrees; where n is an even number from 6 to 50.

In some specific embodiments, the thickness of the diverter plate is 10-1000 μm, and the height h of the top of the protrusion from the center of the material hole of the diverter element is 0.5 mm-20 mm; the thickness of the circular plate is 10-1000 μm. Diameter is 10-300mm.

In some embodiments, the maximum equivalent diameter of the splitter plate is no larger than the diameter of the circular plate.

In some specific embodiments, the equivalent diameter of the material hole of the diverter element is 0.5-20 mm.

In some specific embodiments, the swirl element includes at least three swirl blades, and the swirl blades are arc-shaped or linear.

In some specific embodiments, the thickness of the swirl blades is 0.3-5mm, the height is 2-50mm, and the diameter of the swirl bottom plate is not larger than the diameter of the circular plate.

In some specific embodiments, the material holes 4-1 of the mixing chamber are alternately connected to the middle feeding chamber 3-1 and the bottom feeding chamber 2-1. The material hole 4-1 of the mixing chamber is connected to the bottom feeding chamber 2-1 through the material hole A.

In some specific embodiments, the material hole of the diverting element is provided at a groove connecting two adjacent protrusions.

The beneficial effects of the present invention are as follows:

The micromixer is designed as a detachable structure, which is easy to process, repair and reuse, which reduces the processing difficulty and usage cost of the micromixer.

The micromixer stacks multiple splitter plates and multiple circular plates in a staggered sequence. The splitter plate is equipped with a convex structure. The splitter plate and the circular plates on both sides form an gradually expanding fluid microchannel, which divides the macroscopic fluid into It has a thin fluid layer with micron thickness. The tiny thin layer of fluid flows into the mixing chamber. After being superimposed layer by layer, the mutual diffusion time is shortened, which reduces the mixing time between materials and improves the mixing efficiency of the materials. The height of the protrusions on the manifold can be designed according to the fluid and flow requirements, and can be suitable for mixing fluids of different properties. The thickness and maximum diameter of the splitter plate and circular plate can be changed according to process conditions, which not only takes advantage of the uniform mixing advantages of micro-mixing technology, but also meets the needs of large flow rates in industrial applications.

When the flow rate of the micromixer increases, one advantage of the splitter plate is that the mixing efficiency of the micromixer of the present invention can be maintained high by adjusting the number of material holes and the distance to the boundary of the circular plate while the overall pressure drop remains unchanged. .

Designing the mixing chamber wall as a stepped wall can enable the fluid entering the mixing chamber to leave the wall in advance, avoiding uneven mixing of low-flow fluids caused by wall attachment problems, thereby increasing mixing efficiency.

Design at least three swirl elements with swirl blades to gather the fluid and create a swirl strengthening effect on the fluid, increase the degree of fluid turbulence, disturb the fluid, further enhance the mixing effect of the fluid at low Reynolds numbers, and improve the mixing efficiency.

This invention makes full use of the characteristics of high-efficiency mass transfer in microchannels and avoids the shortcomings of low flux of general micromixers and uneven mixing of conventional mixers. It uses multiple diverter plates and multiple circular plates to form a flux-adjustable mixer. High-throughput micromixer.

The fluid of the present invention flows from the inside to the outside. Compared with the outside-in mixer, the structural design is not limited by the size of the central tube. When the flow rate increases, the diameter of the feed position can be increased accordingly, and the microchannel splitting element can be adjusted by adjusting the microchannel splitting element. The diameter ensures an appropriate distance from the feed to the fluid flow in the mixing chamber, thereby achieving a reasonable design of microchannel shunt components under large flow rates.

Description of drawings

Figure 1 is the internal structure diagram of a high-throughput passive cyclone-enhanced micromixer.

FIG. 2 is a top view of the middle feed distributor in FIG. 1 .

Figure 3 is a three-dimensional structural view of the microchannel flow splitting element in Figure 1.

FIG. 4 is a top view of the swirl element in FIG. 1 .

Figure 5 is a mixing effect diagram of the micromixer.

Among them, a is the main view full-section mixed rendering, and b is the exit cross-section mixed rendering.

Figure 6 is a diagram of the mixing effect of the micromixer in the literature.

Among them, a is the main view full-section mixed rendering, and b is the exit cross-section mixed rendering.

Figure 7 is a mixing effect diagram of a micromixer equipped with a swirl element.

Among them, a is the main view full-section mixed rendering, and b is the exit cross-section mixed rendering.

In the picture: 1. A feed pipe, 2. Bottom feed distributor, 2-1, bottom feed chamber, 3. Middle feed distributor, 3-1, middle feed chamber, 3-2, A material Hole, 3-3, middle feed distributor bolt hole, 4, mixing chamber, 4-1, mixing chamber material hole, 4-2, mixing chamber inner wall, 4-3, mixing chamber, 5, micro channel Diversion element, 5-1, circular plate, 5-2, diverter plate, 5-3, material hole of the diverter element, 5-4, protrusion, 5-5, positioning hole of the diverter element, 6, fixing bolt, 7. Upper cover, 8. Outlet pipe, 9. Diversion positioning pin, 10. Swirl component, 10-1, Swirl blade, 10-2, Swirl bottom plate, 10-3, Swirl component positioning hole, 11. Sealing Rings 1, 12, sealing rings 2, 13, B feed pipe, 14, sealing rings 3, 15, fixing nut.

Detailed ways

The specific embodiments of the present invention will be described below with reference to the accompanying drawings.

Figure 1 shows a high-flux passive cyclone-enhanced micromixer. In the figure, this micromixer includes an A feed pipe 1, a bottom feed distributor 2, a middle feed distributor 3, and a mixing chamber. 4. Microchannel splitting element 5, upper cover plate 7, outlet pipe 8, swirl element 10, B feed pipe 13.

The bottom feed distributor 2 includes a bottom feed cavity 2-1 connected to the A feed pipe 1, and the middle feed distributor 3 includes a middle feed cavity 3-1 connected to the B feed pipe 13. The middle feed distributor 3 The outer periphery of the upper middle feed chamber 3-1 is provided with an A material hole 3-2 that penetrates the middle feed distributor (as shown in Figure 2).

The bottom of the mixing chamber 4 is provided with a mixing chamber material hole 4-1. The mixing chamber material hole 4-1 is evenly distributed on the same circumference as the A material hole 3-2. The mixing chamber 4 is provided with a ladder structure made of The inlet is a mixing chamber 4-3 that gradually expands toward the outlet. The material holes 4-1 of the mixing chamber are alternately connected to the middle feeding chamber 3-1 and the bottom feeding chamber 2-1. The material hole 4-1 of the mixing chamber is connected to the bottom feeding chamber 2-1 through the material hole A.

The microchannel flow splitting element 5 is placed in the mixing chamber 4-3. The microchannel flow splitting element 5 includes circular plates 5-1 and splitter plates 5-2 stacked alternately in sequence. The outer periphery of the splitter plate 5-2 is alternately provided with protrusions 5. -4. The splitter plate 5-2 and the adjacent circular plate 5-1 form an outwardly expanding micro-channel, and the adjacent splitter plates 5-2 are staggered (as shown in Figure 3).

The microchannel diverter element 5 is provided with a diverter element material hole 5-3 at a position corresponding to the mixing cavity material hole, and a diverter element positioning hole 5-5 is provided in the middle of the microchannel diverter element 5.

The swirl element 10 adopts a structure in which a plurality of evenly distributed swirl blades 10-1 are arranged on the swirl bottom plate 10-2. The swirl bottom plate 10-2 of the swirl element 10 is connected to one end of the microchannel diverter element 5, and the outer edge side It is connected to the mixing chamber 4-3, and the middle part is connected to the outlet pipe 8 (as shown in Figure 4).

The upper cover plate 7 is placed above the mixing chamber 4, and the top is connected to the outlet pipe 8. The swirl element 10 is provided in the inner cavity of the upper cover plate 7 that communicates with the mixing chamber 4-3.

The swirl element 10 , the microchannel diverter element 5 , and the mixing chamber 4 are positioned through diverter positioning pins 9 .

The bottom feed distributor 2 and the middle feed distributor 3 are sealed by a sealing ring 14, the middle feed distributor 3 and the mixing chamber 4 are sealed by a sealing ring 12, and the mixing chamber 4 and the upper cover plate 7 are sealed by a sealing ring 11 .

The bottom feed distributor 2, the middle feed distributor 3, the mixing chamber 4 and the upper cover plate 7 are connected and fixed by fixing bolts 6 and fixing nuts 15.

The mixing process of materials in this high-throughput passive cyclone-enhanced micromixer: Taking the mixing process of material A and material B as an example, material A enters the bottom feed chamber 2 from the A feed pipe 1, and then from the bottom feed chamber 2 It flows through the material hole 3-2 of A and enters the material hole 4-1 of the partial mixing chamber; the material B enters the middle feeding chamber 3-1 from the B feeding pipe 13, and then enters the mixing chamber through the middle feeding chamber 3-1. hole 4-1; material A and material B in the material hole 4-1 of the mixing cavity enter the material hole 5-3 of the diversion element of the microchannel diversion element 5, and flow out from the microchannel respectively, forming a fluid thin film with a thickness of microns. layer and enters the mixing chamber 4-3 for mixing; the mixed materials flow into the cyclone element 10 for intensive mixing, and finally flow out from the outlet pipe 8.

Example 1

Compare the present invention with the micromixer reported in the literature (Y. Men, V. Hessel, etc. Trans IChemE, Part A, Chem EngRes Des, 2007,85(A5):605-611.), in order to ensure the comparison conditions In order to ensure the consistency, this embodiment uses the same layer number of microchannel shunt elements without swirl elements.

Structural parameters: The micromixers of the present invention and those reported in the literature are both equipped with 65 circular plates and 65 diverter plates. The thickness is 0.1mm, the diameter of the circular plates is 22mm, and the equivalent diameter of the material hole of the diverter element is 1.5mm. . The number of steps in the mixing chamber of the present invention is 5. Each step is 1 mm high and 0.5 mm wide. The centers of the material holes of the diverter element are evenly distributed on the circumference with a diameter of 10 mm. Comparative literature The conical bottom of the micromixer has a diameter of 4.8mm and a height of 15mm.

Simulation parameters: Using Fluent software, using component transport as the model, the diffusion coefficient of the substance is 2.3e-9m ² /s, and the flow rate is 430L/h. Until the calculated outlet parameters are stable and the residuals converge, then use the following formula Calculate the micromixer outlet mixing efficiency η:

As shown in Figure 5, the mixing efficiency of the present invention without swirl elements is 92%. As shown in Figure 6, the mixing efficiency of the comparative literature under this working condition is 80%. It can be seen that under the same structural parameter conditions, the efficiency of the micromixer of the present invention is better than that of the literature micromixer. Reason analysis: There is a conical structure in the middle of the micromixer in the literature, which causes the low-speed fluid to adhere to the wall, making the fluid mixing effect poor at the center of the outlet section, resulting in low overall efficiency; the micromixer of the present invention flows from the inside to the outside, and the speed gradually increases. The reduction facilitates the mixing of the two fluids in the mixing chamber, and a stepped wall is provided in the mixing chamber to avoid the phenomenon of fluid adhesion, making the efficiency higher.

Example 2

In order to prove the strengthening effect of the swirl element on the present invention, the mixing effect of the micromixer of the present invention with and without the swirl element was compared. Structural parameters of this embodiment: the radius of curvature r of the swirl blades is 11 mm, the thickness t is 0.5 mm, and the height is 4 mm. There are a total of 6 evenly distributed swirl blades. Other structural parameters are the same as those of the present invention in Embodiment 1. .

The simulation parameters are the same as those in Example 1. As shown in Figure 7, the mixing efficiency of the micromixer (including the swirl element) of the present invention is 97%, which is higher than the efficiency of the micromixer without the addition of the swirl element, which is 92%. The results show that the swirl element strengthens the fluid mixing process and improves efficiency.

The above are only some implementation examples of the present invention, and do not impose any formal restrictions on the present invention. Any skilled person familiar with this field can make use of the structures and technologies disclosed above without departing from the scope of the technical solution of the present invention. The content has been modified to become an equivalent implementation case with equivalent changes.

For example, the present invention does not limit the number of feeding units. The number of feeding units can be increased or reduced according to the actual required number of mixed materials. In this case, the material holes of the feeding units only need to be allocated accordingly.

Without departing from the content of the solution of the present invention, those of ordinary skill in the field may make any simple modifications, equivalent changes and modifications to the above embodiments based on the technology of the present invention without making other creative efforts. Modifications are within the scope of the technical solution of the invention.

Claims (5)

1. The utility model provides a little blender is reinforceed to passive whirl of high flux, includes bottom feeding distributor, middle part feeding distributor, mixing chamber body, microchannel reposition of redundant personnel component and the mixing chamber upper cover plate that connects gradually, its characterized in that: the bottom feeding distributor comprises a bottom feeding cavity communicated with the feeding pipe A, the middle feeding distributor comprises a middle feeding cavity communicated with the feeding pipe B, and the periphery of the middle feeding cavity is provided with a material hole A penetrating through the middle feeding distributor;

the bottom of the mixing cavity is provided with a plurality of mixing cavity material holes, and a gradually-expanding mixing cavity structure is arranged along the outlet direction, and the wall surface of the mixing cavity is a stepped wall surface;

the micro-channel flow dividing element is arranged in the mixing cavity and comprises flow dividing plates and circular plates which are sequentially stacked in a staggered mode, bulges are arranged on the periphery of the flow dividing plates, micro-channels which are gradually expanded from inside to outside are formed by the flow dividing plates and adjacent circular plates, and the adjacent flow dividing plates are arranged in a staggered mode; the micro-channel flow dividing element consisting of the flow dividing plate and the circular plate is provided with a through flow dividing element material hole at a position corresponding to the material hole of the mixing cavity; the upper cover plate of the mixing cavity is communicated with the outlet pipe;

the micro mixer further comprises a rotational flow element, one end of the rotational flow element is connected with the micro channel flow dividing element, the other end of the rotational flow element is connected with the upper cover plate, and the rotational flow element adopts a structure that a plurality of rotational flow blades are arranged on a rotational flow bottom plate;

the number of steps of the step wall surface is 3-10, the height is 0.5-5mm, and the width is 0.1-5mm;

the number of the flow dividing plates is 10-500, the protrusions on the flow dividing plates are elliptical, circular or triangular, the number of the protrusions is n, and the staggered angle between the adjacent flow dividing plates is 180/n degrees; wherein n is an even number from 6 to 50;

the thickness of the flow dividing plate is 10-1000 mu m, and the height h between the top end of the bulge and the center of the material hole of the flow dividing element is 5-20 mm; the thickness of the circular plate is 10-1000 mu m, and the diameter is 10-300mm.

2. A high throughput passive cyclone-intensified micromixer according to claim 1, wherein: the maximum equivalent diameter of the splitter plate is no greater than the diameter of the circular plate.

3. A high throughput passive cyclone-intensified micromixer according to claim 1, wherein: the equivalent diameter of the material hole of the flow dividing element is 0.5-20mm.

4. A high throughput passive cyclone-intensified micromixer according to claim 1, wherein: the swirl element comprises at least 3 swirl blades which are arc-shaped or straight-line-shaped.

5. A high throughput passive cyclone-intensified micromixer according to claim 4, wherein: the thickness of the cyclone blade is 0.3-5mm, the height is 2-50mm, and the diameter of the cyclone bottom plate is not larger than that of the circular plate.