KR100880005B1 - Split and recombine micro-mixer with chaotic mixing - Google Patents

Abstract

An SAR micromixer having chaotic mixing is provided to allow the separation and the mixing to be carried out repeatedly, thereby improving the mixing efficiency of two fluids. An SAR micromixer having chaotic mixing comprises an input hole, a mixture channel part and an output hole to mix different fluids, wherein the mixture channel part comprises first and second channel plates(20a, 20b) which have a center penetration hole(21) and a channel penetration hole(22) formed radially; a first partition(30a) installed to be in contact with the first channel plate and having a penetration hole at the center; and a second partition(30b) installed to be in contact with the second channel plate and having an outer penetration hole(32) at the part in contact wit the outermost side of the second plate channel penetration hole.

Description

SARR micromixer with chaotic mixing {Split and Recombine Micro-mixer with Chaotic Mixing}

The present invention relates to a SAR micro mixer with chaotic mixing, and more particularly, to provide a mixer model integrating a SAR mixer and a chaotic mixer, which are passive mixers among the micromixers, into a stable mixer for a high speed of the SAR mixer. Cao capable of rapid mixing between two liquids such as chaotic mixing in the SAR model by forming projections in the channel through which the fluid flows to induce the mixing function and the chaotic flow of the chaotic mixer to increase the mixing efficiency. A SAR micromixer with tick mixing is provided.

Methods of mixing the fluid include turbulent mixing and mixing by diffusion. In the case of the turbulent mixing, by using a large Reynolds number to rotate the propeller in the fluid, or by introducing a moving auxiliary member such as magnetic beads (magnetic bead) into the fluid to induce turbulent flow (turbulent flow) through them Effective fluid mixing. However, in the case of the micro-micro system, the number of Reynolds is greatly reduced and turbulence is not formed in addition to the laminar flow, so a mixing method by diffusion is used.

In other words, different fluids having a Reynolds number of 1000 or less are mixed by diffusion, and it is possible to increase the contact area of different fluids in order to increase the diffusion effect in mixing a low Reynolds number fluid. The micromixer is a form in which a typical laminar flow exists, and such a micromixer is divided into an active type and a passive type according to a method of inducing mixing.

The active mixer is a form that helps the mixing of the fluid by receiving energy from the outside generally requires a complicated manufacturing process and has a special structure to deliver energy to the fluid. Typical active mixers include magnetic stir bars and acoustic cavitation cells.

On the contrary, the passive mixer improves the mixing characteristics by using the structural characteristics of the channel. The passive mixer has the characteristics that are easier to manufacture than the active type and can be applied to various channel structures. These passive mixers are divided into chaotic mixers that induce chaotic flow in the channel to increase mixing efficiency and split and recombine (SAR) mixers that improve efficiency by performing separation and mixing processes repeatedly.

The chaotic mixer is described in A.D. Since Stroock's thesis, many related studies have been conducted. The mixing rate was improved through patterning inside the channel for fluids with Reynolds numbers below 100. SAR mixers are generally known to achieve stable mixing even at high flow rates and are the most widely used in engineering.

As such, the chaotic mixer and the SAR mixer have been actively researched separately, but the development of a hybrid type combining the advantages of each is insufficient.

SAR micromixer with chaotic mixing of the present invention for solving the above problems,

In the micro mixer for mixing the different fluids consisting of the inlet for the fluid inlet and the mixing channel portion formed with a channel through which the inflowing fluid flows and the outlet for discharging the mixed fluid, the mixing channel portion, the central hole is formed in the center First and second channel plates having a flow path formed radially long about the center hole; A first plate installed in contact with the first channel plate and having a hole formed in the center thereof; A second plate installed in contact with the second channel plate and having an outer hole formed at a portion in contact with the outermost side of the second channel plate passage hole;

In addition, a plurality of diffusion protrusions are formed on one surface or both surfaces of the first and second partition plates in the lengthwise direction of the flow path holes at portions contacting the flow path holes formed in the first channel plate and the second channel plate.

The diffusion protrusions formed on the first and second plates are obtuse vertices at the inflow portion of the fluid and the fluid discharge portion is at the bottom, so that both inclined surfaces protrude from the obtuse vertices. The protruding height of the diffusion protrusions formed on the first plate and the second plate may be 15 to 60 μm.

The first channel plate and the second channel plate, which are respectively attached to both surfaces of the first plate, may be formed to be twisted at regular angles on the same axis, and the channel holes formed in the first channel plate and the second channel plate may have eight channels. And, it can be arranged so as to have an equiangular center around the center hole.

As described in detail above, the SAR micro mixer with chaotic mixing of the present invention,

The diffusion protrusion of the chaotic mixer is formed on the channel of the SAR mixer which can provide various channel structures. As the fluid flows through the chaotic flow, the separation and mixing are repeated, thereby improving the mixing efficiency of the two fluids.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

1 is an overall perspective view of a micromixer according to a preferred embodiment of the present invention, Figure 2a is a separate perspective view showing a channel and a diaphragm in the mixing channel portion according to the present invention, Figure 2b is a channel composed of Figure 2a And a cross-sectional view showing a state in which a plurality of diaphragms are stacked.

SAR micro mixer 10 with chaotic mixing according to the present invention is mounted to the body having a mixing channel portion 13 and one side end of the body as shown in Figure 1 for introducing two different fluids into the body It consists of two inlets 11 and the outlet 12 is mounted to the other end of the body for discharging the fluid passing through the mixing channel portion.

As shown in FIG. 2A, the mixed channel part 13 is a thin plate composed of a first channel plate 20a, a first plate 30a, a second channel plate 20b, and a second plate 30b. Stacking configuration to form a channel through which the fluid is moved.

The first channel plate 20a and the second channel plate 20b have a central through hole 21 formed at the center thereof, and a flow through hole 22 is formed radially with respect to the central through hole. To flow from outside to center or from center to outside. As illustrated, the flow path through holes 22 may be formed in eight, or may be formed in various numbers such as four or twelve.

The first plate 30a has a through hole 31 formed in the center thereof. The through hole is formed to have the same size as the center through hole 21 formed in the first and second channel plates 20a and 20b. To be moved to the rear channel plate. In addition, the second plate 30b is formed with an outer through hole 32 in a portion in contact with the outermost side of the flow passage hole 22 formed in the first (20a) and the two channel plate (20b), so that the fluid in front of the rear plate (30b) Allow it to flow.

Referring to a portion of the mixing channel portion 13 configured as described above, as shown in FIG. 2B, the two fluids introduced into the outer through hole 32 of the second plate 30b are respectively the first channel plate. It flows to the center through-hole 21 along the flow path 22 of 20a, and passes through the through-hole 31 of the 1st partition plate 30a to the center through-hole 21 of the 2nd channel plate 20b. In the second channel plate flows outward from the central hole 21 along the flow path hole 22, and is moved from the center to the outside while moving to the other channel plate through the outer hole 32 of the second plate (30b). The process of being separated and then merged again from the outside to the center is repeated.

3A is a perspective view illustrating a plate and a channel plate having diffusion protrusions according to another embodiment of the present invention, and FIG. 3B is a cross-sectional view illustrating a state in which a plate and a channel plate formed of FIG. 3A are stacked. It is sectional drawing which shows the state in which the plate | board with the diffusion protrusion formed on both surfaces was laminated | stacked.

As shown in the drawing, a diffusion protrusion 33 is formed at a portion of the first plate 30a and the second plate 30b in contact with the passage hole 22. The diffusion protrusion 33 is a plurality of protruding in the longitudinal direction of the passage hole 22 so that the fluid flowing has a chaotic flow. The diffusion protrusions 33 may be formed on both sides of the diaphragms 30a and 30b as shown in FIG. 3c so that the diffusion protrusions may protrude on both sides of the channel formed by the diaphragms and the channel plates 20a and 20b.

4A is a plan view showing a portion of a substrate on which a diffusion protrusion is formed according to the present invention, and FIG. 4B is an enlarged plan view of the diffusion protrusion. As shown in the drawing, the diffusion protrusion 33 is formed at a portion of the channel plate 20a and 20b that is in contact with the flow passage hole 22, and the fluid inflow portion is an obtuse vertex and the fluid discharge portion is at the bottom side. The oblique vertex is formed in a shape of “s” protruding from both inclined surfaces. In addition, the base L1 and L2 separated by an inner line connecting the obtuse vertex and the bottom may be formed to be 6: 4 so that the length of the inclined surface may be differently formed.

The diffusion protrusion 33 entangles the fluids by moving the laminar flow in the channel to the inclined diffusion protrusion 33 so that the traveling speed is different. In this process, the lengths of the inclined surfaces on both sides of the diffusion protrusion 33 are increased. Alternatively, the entanglement process can be asymmetrical, resulting in more complex entanglement than symmetry, which can increase the contact area. In addition, the diffusion protrusion 33 is preferably formed to a height of 15 ~ 60㎛ the protrusion height into the channel. When it is formed in the 15㎛ or less, the provision of chaotic flow is inadequate, when formed in 60㎛ or more is preferably formed in the above range by inhibiting the fluid flow.

5 is a schematic view showing a state in which the first channel plate and the second channel plate are twisted, and as shown, the first channel plate 20a and the first channel plate 20a which are installed in contact with one surface and the other surface of the first plate 30a. The two channel plate 20b is formed to be twisted at a predetermined angle on the same axis so that the flow path holes 22 formed in each channel plate are shifted from each other so that the fluid is diaphragm 30a, 30b and the channel plate 20a, 20b. In the moving path that is separated to the outside while passing through and then merged inward to move along the axis at a predetermined angle to each other to improve the mixing efficiency. At this time, the twisted angle is 45 degrees when the eight passage holes are formed as shown, so the angle between the passage hole is 45 °, it is possible to be twisted 22.5 ° so that the passage hole of the other channel plate between the two passage holes. In addition, when using the channel plate formed with four passage holes, the torsion angle can be formed to 45 °.

Hereinafter, the fluid flow of the SAR micromixer having chaotic mixing according to the present invention will be described in detail through the following examples.

The micromixer of the present invention combines a chaotic mixer and a SAR mixer to increase the efficiency of mixing by adding chaotic flow to the mixed fluid while repeatedly performing separation and mixing of the fluid. In order to carry out this study, we used a commercial program, CFD-ACE +.

Numerical analysis was performed on the model of the paper published in Science to quantify the mixing efficiency according to the mixer length, and the effect of the ridge height for chaotic mixing was analyzed by the numerical analysis on the same model.

The SAR model was analyzed by numerical analysis in the same way, and the effect was analyzed by designing the ridge in the channel through which the fluid moves to enable chaotic mixing.

In the problem of mixing between different liquids, if the difference in viscosity and density between two liquids is small and the difference in physical properties does not significantly affect the flow field, the physical properties of the two liquids can be assumed as one representative value. In such cases, the flow field can be analyzed and additional transport equations can be defined to solve the solution and address the mixing problem. However, if the flow field is affected by the difference in physical properties between the two liquids, the physical properties of each liquid and the change in physical properties of the two liquids should be considered. CFD-CAE used in this experiment did not support the density calculation model according to the degree of mixing between two liquids in the case of liquid mixing, so the density was defined using the user subroutine. In the case of viscosity, Mix Polynomial in T ( The Liq) model was used to define the viscosity of the mixture according to the mass fraction of the chemical species.

In addition, the diffusion coefficient is assumed to be a constant, Table 1 shows the liquid used in the numerical analysis and its physical properties.

After the numerical analysis by the above method, the mixing efficiency was calculated using Equation 2 to quantify the degree of mixing between the two liquids.

Example 1  - Chaotic Mixing  Translate

The model of FIG. 6 was used to calculate the mixing efficiency of the channel with the diffusion protrusions. The model shows the chaotic mixing effect through experiments and shows the result of mixing when the fluid passes about 3cm in length.

In Example 1, the channel width, ridge width, angle, and height of the model were the same, and the analysis was performed by limiting the channel length to 6 mm only in consideration of the analysis environment.

FIG. 7 is a graph showing the mixing efficiency at the exit when 12 diffusion protrusions pass as one set of 12 diffusion protrusions in FIG. 6. In addition, the mixing efficiency when increasing the height of the diffusion projections from 15㎛ to 60㎛ is also shown in FIG. For the effect of the height of the diffusion projections, only 12 ridges were included in the analysis to calculate the mixing efficiency at the outlet.

As shown in FIG. 7, the mixing efficiency increased proportionally as the length of the channel increased, but when the length of the channel increased from 1.5 mm to 3 mm, the mixing efficiency increased about 2 times as the channel length increased, but the length of the channel increased. Increasing the mixing efficiency decreased.

This phenomenon also appeared when the height of the diffusion protrusions increased, and the increase of the mixing efficiency decreased significantly when the height of the diffusion protrusions was 45 ㎛ or more.

Example 2  - SAR  Translate

As shown in FIG. 8, a mixture of two fluids is performed while repeatedly performing separation and coupling with each other. FIG. 8 is a model with diffused projections and the SAR analysis was performed on a 1/8 model like FIG. 9 without diffused projections. 9 shows the color mixing of the two fluids.

Example 3  - Diffused projections  Formed SAR  Translate

Chaotic mixing was induced by adding a diffuser to the channel of the SAR model of Example 2. FIG. 10 shows the analysis results according to the number of overlapping mixers in comparison with the SAR model of Example 2, and FIG. 11 graphically shows the mixing efficiency at the exit of each layer.

As shown in FIG. 10, it can be seen that the mixing efficiency of about 6 to 10% is improved according to the number of overlapping layers. As a result of the analysis up to the fourth layer, the mixing efficiency of 89.9% was finally obtained, and this result is about 6.7% improvement compared to 83.2% of the SAR model 2 without chaotic mixing.

In addition, the above-mentioned example is only an example to demonstrate this invention. Therefore, it is obvious that the ordinary skilled in the art to which the present invention pertains uses the partial change with reference to the detailed description.

1 is an overall perspective view of a micromixer according to a preferred embodiment of the present invention.

Figure 2a is an exploded perspective view showing the channel and the diaphragm in the mixing channel portion in accordance with the present invention.

2B is a cross-sectional view showing a state in which a plurality of channels and diaphragms formed in FIG. 2A are stacked;

Figure 3a is a perspective view showing a plate and a channel plate is formed with a diffusion protrusion according to another embodiment of the present invention.

3B is a cross-sectional view illustrating a state in which a diaphragm and a channel plate of FIG. 3A are stacked.

Figure 3c is a cross-sectional view showing a state in which the diaphragm is formed with diffusion projections on both sides.

Figure 4a is a plan view showing a portion of a substrate on which a diffusion protrusion according to the present invention is formed.

Figure 4b is a plan view showing an enlarged diffusion projection.

5 is a schematic view showing a state in which the first channel plate and the second channel plate are twisted and installed.

6 is a schematic view showing a model in which diffusion protrusions are formed.

7 is a graph showing the mixing efficiency according to the channel length and the height of the diffusion projection.

8 is a schematic diagram of a SAR mixer with chaotic mixing.

9 is a mixing process diagram showing the results of mixing ratio calculation using a SAR mixer.

10 is a comparative view comparing the mixing results of Example 2 and Example 3 by layer.

11 is a graph showing the mixing efficiency of Example 2 and Example 3.

<Explanation of symbols for the main parts of the drawings>

10: micromixer 11: inlet

12 outlet 13 mixed channel portion

20a, 20b: first and second channel plate 21: center hole

22: Euro through 30a, 30b: First and second plate

31: through air 32: through air

33: diffusion protrusion

Claims (7)

In the micromixer 10 for mixing different fluids consisting of an inlet 11 for introducing a fluid and a mixing channel portion 13 having a channel through which the inflowed fluid flows, and an outlet 12 for discharging the mixed fluid. , The mixing channel unit 13, A first (20a) and a second channel plate (20b) having a central through hole (21) formed in the center and having a passage hole (22) extending radially about the central through hole; A first plate 30a installed in contact with the first channel plate 20a and having a hole formed in the center thereof; A second partition plate 30b installed in contact with the second channel plate 20b and having an outer hole 32 formed at a portion of the second channel plate passage hole in contact with the outermost side thereof; SAR micromixer with chaotic mixing. The method of claim 1, On one surface of the first plate 30a and the second plate 30b, a plurality of flow path holes are formed in contact with the flow path holes 22 formed in the first channel plate 20a and the second channel plate 20b. SAR micromixer with chaotic mixing, characterized in that the diffusion projection (33) of the. The method of claim 1, On both sides of the first plate 30a and the second plate 30b, a plurality of passage holes are formed in contact with the passage holes 22 formed in the first channel plate 20a and the second channel plate 20b. SAR micromixer with chaotic mixing, characterized in that the diffusion projection (33) of the. The method according to claim 2 or 3, The diffusion protrusions 33 formed on the first and second plates are obtuse vertices at which the fluid is introduced, and the fluid discharge part is at the bottom, and the “s” characters having both inclined surfaces protruding from the obtuse vertices. SAR micromixer with chaotic mixing characterized in that it has a shape. The method according to claim 2 or 3, SAR micromixer having a chaotic mixing, characterized in that the protrusion height of the diffusion protrusions 33 formed in the first and second plate is formed to 15 ~ 60㎛. The method of claim 1, SAR micromixer having chaotic mixing is characterized in that the first channel plate 20a and the second channel plate 20b, which are installed in contact with both surfaces of the first plate 30a, are formed at a predetermined angle on the same axis. . The method of claim 1, SAR micro with chaotic mixing, characterized in that formed in the first channel plate and the second channel plate 22 is formed to have an equiangular center around the center hole 21 mixer.

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