CN117753268A - Micro-mixing channel and spiral micro-mixing device - Google Patents

Abstract

The invention belongs to the field of micro-mixing of micro-fluidic technology. The invention discloses a micro-mixing channel and a spiral micro-mixing device, and aims to solve the problems that an existing micro-mixing channel structure is large in liquid path mixing dead volume, easy to gather and difficult to discharge bubbles, high in cleaning difficulty, high in pressure drop born by a mixer and the like. The Dean vortex in the micro-channel strengthens the mass transfer process of materials due to the disturbance of the sine wall surface structure, thereby improving the mixing efficiency. Under the same mixing efficiency, the micro-mixing structure provided by the invention has smaller pressure drop, lower energy consumption in the practical application process and stronger applicability and practicability.

Description

Micro-mixing channel and spiral micro-mixing device

Technical Field

The invention relates to the field of micro-mixing of micro-fluidic technology, in particular to a micro-mixing channel and a spiral micro-mixing device.

Background

The microfluidic technology can realize miniaturization and automation of complex flow path treatment, and is widely applied to the fields of medicine, biology, water environment monitoring and the like. The micro-mixing unit is an important component of the microfluidic analysis system, and the micro-mixing device determines the monitoring flux of the analysis system to a great extent, so that the research on the efficient micro-mixing structure and method is important to the improvement of the performance of the analysis system. The traditional spiral micromixer has the characteristics of simple structure, uniform and single inner and outer diameters, low mixing efficiency, usually prolonged channel length or serial connection of a plurality of micromixers of the same type to improve the mixing efficiency, reduced time resolution of an analysis system, increased consumption of water samples and reagents and system power consumption, and increased volume of the analysis system.

In order to improve the defects of the spiral structure, the micro-mixing structure and the mixer have the defects of L-shaped (patent ZL202111238082. X), H-shaped (DOI: 10.1016/J. CES. 2012.03.036), omega-shaped (DOI: 10.3390/mi 6070953), micro-mixing structure with embedded barriers or baffles (DOI: 10.1016/j. Cherd. 2013.09.008) in the micro-channels, the micro-mixing structure and the mixer can better improve the mixing efficiency of the spiral structure, but are limited by the structural characteristics, and have the defects of large dead volume of liquid path mixing, difficult air bubble aggregation, high cleaning difficulty, high pressure drop born by the mixer and the like.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a micro-mixing channel and a spiral micro-mixing device which have high mixing efficiency, low pressure drop, low power consumption and high space utilization and are easy to clean.

In order to achieve the above purpose, the technical scheme of the invention is as follows:

in a first aspect, the present invention provides a micro-mixing channel having sinusoidal walls.

Further, the sinusoidal wall surface includes a single outer sinusoidal wall surface and a single inner sinusoidal wall surface.

Further, the sine wall surface is formed by combining N sine structures with the same unit cycle number, the same unit cycle number and different unit cycles with the same amplitude and the same unit cycle with different amplitudes; n is more than or equal to 2.

Further, the sine wall surface also comprises a material inlet and a material outlet.

Further, the material inlet and the material outlet are designed to be collinear in the center.

Further, the amplitude and the unit period of the sine wall surface are adjustable.

Further, the sinusoidal wall design is according to the polar equation of equation (1):

r＝i+jsin[mod(kθ，2π)] (1)

where r represents the sinusoidal wall radius and i, j and k represent the spiral microchannel radius, the sinusoidal function wall amplitude and the number of cell cycles, respectively.

In a second aspect, the present invention provides a spiral micro-hybrid device comprising upper, middle and lower three layers of chips;

the upper chip comprises a material inlet and a micro-mixing channel communicated with the material inlet; the micro-mixing channel is provided with a sine wall surface;

the middle chip is provided with a fluid inlet which is communicated with the outlet of the micro-mixing channel; the lower chip is provided with a connecting channel which is communicated with the fluid inlet; the connecting channel is connected with a material outlet.

Further, two material inlets are arranged, and the two material inlets are communicated to the micro-mixing channel through a Y-shaped material intersection channel.

Further, the sinusoidal wall design is according to the polar equation of equation (1):

r＝i+jsin[mod(kθ，2π)] (1)

where r represents the sinusoidal wall radius and i, j and k represent the spiral microchannel radius, the sinusoidal function wall amplitude and the number of cell cycles, respectively.

Compared with the prior art, the invention has the beneficial effects that:

1. the Dean vortex in the spiral micro-channel strengthens the mass transfer process of materials due to the disturbance of the sine wall surface structure, thereby improving the mixing efficiency;

2. the wall function can be applied to various arc micro-hybrid structures;

3. the mixing structure is simple, the processing and the manufacturing are easy, and the production cost is low;

4. the mixing structure has no dead angle, so that the problems of bubble accumulation and the like can be avoided, and the stability of flow detection is ensured;

5. under the same mixing efficiency, the micro-mixing structure provided by the invention has smaller pressure drop, lower energy consumption in the practical application process and stronger applicability and practicability.

Drawings

FIG. 1 shows a single-sided outer wall sinusoidal wall micro-mixing channel provided in embodiment 1 of the present invention;

FIG. 2 shows a single-sided inner wall sinusoidal wall micro-mixing channel according to embodiment 1 of the present invention;

FIG. 3 is a schematic diagram of a spiral micro-hybrid device with a sinusoidal wall structure according to embodiment 2 of the present invention;

FIG. 4 is a schematic diagram of the upper chip structure;

FIG. 5 is a schematic diagram of a middle layer chip;

FIG. 6 is a schematic diagram of the structure of a lower chip;

in the figure: 1. an upper chip; 11. a material inlet; 12. a micro-mixing channel; 13. y-shaped material intersection channels; 14. an upper material outlet; 2. a middle layer chip; 21. a fluid inlet; 22. a middle layer material outlet; 3. a lower chip; 31. a connection channel; 32. and a lower material outlet.

Detailed Description

The technical scheme of the invention is further described below with reference to the accompanying drawings and examples.

Example 1:

referring to fig. 1-2, the present embodiment provides a micro-mixing channel having sinusoidal walls suitable for any micro-mixing channel comprising an arcuate configuration. Therefore, the Dean vortex in the micro-channel strengthens the mass transfer process of the materials due to the disturbance of the sine wall surface structure, thereby improving the mixing efficiency;

specifically, as shown in fig. 1, the design of the sinusoidal wall surface is according to the polar equation of equation (1):

r＝i+jsin[mod(kθ，2π)] (1)

where r represents the sinusoidal wall radius and i, j and k represent the spiral microchannel radius, the sinusoidal function wall amplitude and the number of cell cycles, respectively.

By designing the sine wall surface in this way, the sine wall surface has good disturbance, so that Dean vortex in the micro-mixing channel can be enhanced, and the mixing efficiency of the mixing structure can be improved.

1-2, the sine wall surface comprises, but is not limited to, a single outer sine wall surface and a single inner sine wall surface, and can be formed by combining N (N is more than or equal to 2) sine structures with the same unit cycle number, the same unit cycle number and different unit cycles with the same amplitude and the same unit cycle with different amplitudes; the amplitude and the unit period of the sine wall surface are adjustable.

The sinusoidal wall also includes a material inlet and a material outlet, which may be preferably of a centered collinear design for ease of cascading.

Example 2:

referring to fig. 3, the present embodiment provides a spiral micro-hybrid device with a sine function wall structure, which is formed by bonding three layers of chips, namely, an upper layer, a middle layer and a lower layer, and adopts a design mode of three layers of chip bonding to reduce the processing difficulty of the chip on one hand; on the other hand, the layout design of the micro-channel outlets is facilitated, the fluid flow phenomenon in the micro-mixer is convenient to observe through experiments, the whole chip structure is more in line with the actual use requirement, and the micro-mixer has the characteristics of flexible design of a processing flow path structure, simple process and convenience in cascading.

The upper chip 1 comprises two material inlets 11, a micro-mixing channel 12 and a Y-shaped intersection channel 13 connecting the two material inlets 11 and the micro-mixing channel 12; the micro-mixing channel 12 has a sinusoidal wall that is a single-sided outer wall sinusoidal wall with the following wall structure function:

r＝i+0.05sin[mod(10iθ，2π)]i＝0.7，1.1，1.5，1.9

0≤θ≤π

i＝0.5，0.9，1.3，1.7

π≤θ≤2π

where r represents the sinusoidal wall radius and i represents the spiral microchannel radius.

The middle chip 2 is provided with a fluid inlet 21 to communicate with the outlet of the micro-mixing channel 12; the lower chip 3 is provided with a connection channel 31 to communicate with the fluid inlet 21; the connecting channel 31 is connected with a lower material outlet 32. Of course, the upper chip 1 and the middle chip 2 are also provided with an upper material outlet 14 and a middle material outlet 22, respectively, to correspond to the material outlet 32 of the lower chip 3.

All of the micro-channels of this embodiment, except for the micro-mixing channel 14, are 200um by 200um in size. The micromixer described above was analyzed based on computational fluid dynamics simulation. The results show that the micro-mixing structure of the examples can achieve rapid and uniform mixing of materials. At reynolds number re=40, the mixing effect at the material outlet, i.e. the mixing index, exceeds 0.90. In summary, the micro-mixing device has a simple structure, is not easy to accumulate bubbles, has low material consumption, can realize efficient mixing in a very small space, and is beneficial to stability, timeliness and microminiaturization of detection of an analysis system.

Specifically, the mixing effect was evaluated based on the mixing index (formula 2):

in the method, in the process of the invention,for the volume fraction of the fluid when fully mixed, N is the number of points in cross section, C _i Is the volume fraction at point N.

Under the condition that the Reynolds number is more than or equal to 0.1 and less than or equal to 50, compared with the traditional spiral micro-mixing structure, the mixing effect of the sine wall micro-mixing structure is obviously improved. At a low Reynolds number (Re is more than or equal to 0.1 and less than 40), the mixing effect of the sine wall micro-mixing structure on the inner side wall is best; reynolds number is within the range of 40-50, and the mixing effect of the outer side wall sine wall micro-mixing structure is optimal

The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement the same, and are not intended to limit the scope of the present invention. All equivalent changes or modifications made in accordance with the essence of the present invention are intended to be included within the scope of the present invention.

Claims (10)

1. A micro-mixing channel, wherein the micro-mixing channel has sinusoidal walls.

2. The micro-mixing channel of claim 1, wherein the sinusoidal walls comprise a single outer sinusoidal wall and a single inner sinusoidal wall.

3. The micro-mixing channel of claim 1, wherein the sinusoidal wall is composed of N sinusoidal structures of the same amplitude, the same number of cell cycles, the same amplitude, different cell cycles, and different amplitude, the same cell cycles; n is more than or equal to 2.

4. The micro-mixing channel of claim 1, wherein the sinusoidal wall further comprises a material inlet and a material outlet.

5. The micro-mixing channel of claim 4, wherein the material inlet and the material outlet are of a centered co-linear design.

6. The micro-mixing channel of claim 1, wherein the amplitude, cell period of the sinusoidal walls are adjustable.

7. The micro-mixing channel as claimed in any one of claims 1-6, wherein the sinusoidal wall is designed according to the polar equation of formula (1):

r＝i+jsin[mod(kθ,2π)] (1)

where r represents the sinusoidal wall radius and i, j and k represent the spiral microchannel radius, the sinusoidal function wall amplitude and the number of cell cycles, respectively.

8. The spiral micro-mixing device is characterized by comprising an upper chip, a middle chip and a lower chip;

the upper chip comprises a material inlet which is communicated with the micro-mixing channel; the micro-mixing channel is provided with a sine wall surface;

the middle chip is provided with a fluid inlet which is communicated with the outlet of the micro-mixing channel; the lower chip is provided with a connecting channel which is communicated with the fluid inlet; the connecting channel is connected with a material outlet.

9. The spiral type micro-mixing device according to claim 8, wherein two material inlets are arranged, and the two material inlets are communicated with the micro-mixing channel through a Y-shaped material intersection channel.

10. The spiral micromixer device of claim 8 or 9, wherein the sinusoidal wall is designed according to the polar equation of equation (1):

r＝i+jsin[mod(kθ,2π)] (1)

where r represents the sinusoidal wall radius and i, j and k represent the spiral microchannel radius, the sinusoidal function wall amplitude and the number of cell cycles, respectively.