CN116943497A - A kind of passive micromixer with heart-shaped function structure - Google Patents

Abstract

The invention discloses a passive micromixer with a heart-shaped function structure, which comprises a first fluid inlet channel (1), a second fluid inlet channel (2), a primary mixing channel (3), a micromixer unit group (M) and an outlet channel (4), wherein the micromixer unit group comprises a plurality of heart-shaped function micromixer units (5) which are sequentially connected end to end in a smooth manner, and a combined channel formed by main channels of the first heart-shaped function micromixer units and the second heart-shaped function micromixer units is in a structure of gradually shrinking first and then gradually expanding; the method is characterized in that: the heart-shaped function micromixer unit comprises a main channel, a first diversion channel (8) and a second diversion channel (9). The invention makes the fluid generate secondary flow and vortex with different dimensions in the main channel, and simultaneously makes the fluid continuously split and merge by the split channel, thereby aggravating unbalanced collision between the fluids, generating chaotic convection and vortex-induced mixed flow, improving mixing strength, shortening flow channel length, reducing mixing time and improving mixing effect.

Description

A kind of passive micromixer with heart-shaped function structure

Technical field

The invention relates to the technical field of microfluid mixing, and in particular to a passive micromixer with a heart-shaped functional structure.

Background technique

Microfluidic chip technology can operate the separation, sample addition, mixing, reaction, detection and other functions in the laboratory analysis and detection process in a micron-scale space, so microfluidic chips are also called lab-on-a-chip. The microfluidic mixer is one of the important components of the microfluidic chip. The sealed microchannels and chambers can isolate the contact between people and reagents, ensuring the safety of personnel while preventing reagents from being contaminated. Compared with macro mixers, microfluidic mixers have the advantages of efficient heat transfer, high-speed mixing, rapid system response, and high safety performance, and are widely used in many fields such as medicine, chemical industry, and food.

Currently, microfluidic mixers are divided into active micromixers and passive micromixers according to whether external energy needs to be introduced to enhance the mixing effect. In addition to the energy to pump fluid, active micromixers also require external power, such as sound fields, electric fields, magnetohydrodynamic fields, mechanical stirring, etc., to achieve the desired mixing effect by perturbing the fluid in the microchannel. Active micromixers are difficult to manufacture and have high processing costs. Acoustic field, electric field and other driving will generate heat, which may cause unnecessary side reactions of reagents. Passive micromixers do not require external energy drive except for the energy of pumping fluid. They mainly rely on special geometric channels to promote fluid mixing, such as convergence and divergence structures, stretch and fold structures, and obstacles in the channels. Its advantage is that it has a simple structure and is easy to process and integrate; its disadvantage is that it requires a long mixing channel, the mixing speed is relatively slow, and the mixing time is long.

For example, the prior art discloses that passive microfluidic mixers include "snake-shaped", "S-shaped" and other forms of micromixers. The fluid channel cross-sectional area of each micromixer unit can be equal, gradually reduced, or gradually increased. However, existing micromixers still have the problems of relatively slow mixing speed and relatively long mixing time.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art and provide a passive micromixer with a heart-shaped function structure. Two heart-shaped functions with different curvatures constitute a special channel structure that contracts and expands, so that the fluid (liquid) can Secondary flows and vortices of different scales appear in the main channel. At the same time, the split channels (the first split channel and/or the second split channel) cause the fluids to continuously diverge and merge, exacerbating the unbalanced collision between the fluids and generating chaotic convection and vortices. , vortex-induced mixed flow, which improves the mixing intensity, shortens the length of the flow channel, reduces the mixing time, and improves the mixing effect.

In order to achieve the above objects, the technical solutions adopted by the present invention are:

A passive micromixer with a heart-shaped functional structure, which includes a first fluid inlet channel (1), a second fluid inlet channel (2), a preliminary mixing channel (3), a micromixer unit group (M), and an outlet channel (4), the first fluid inlet channel and the second fluid inlet channel are both connected to the preliminary mixing channel, and the micromixer unit group includes a plurality of heart-shaped function micromixer units (5) that are smoothly connected end to end. The micromixer unit The downstream end of the unit group is connected to an outlet channel, the downstream end of the preliminary mixing channel is connected to the first inlet end (51) of the cardioid function micromixer unit, and the first outlet end (52) of the cardioid function micromixer unit ) is connected to the first inlet end of the next cardioid function micromixer unit, and the combined channel formed by the main channels of the first and second cardioid function micromixer units has a structure that first gradually contracts and then gradually expands; It is characterized in that: the heart-shaped function micromixer unit (5) includes a main channel, a first branch channel (8), and a second branch channel (9). The main channel is composed of a first heart-shaped function curve (6), a second branch channel (9), and a first heart-shaped function curve (6). It is composed of a heart-shaped function curve (7), the inlet end of the first shunt channel is connected to the upper left side of the main channel, the outlet end of the first shunt channel is connected to the lower right side of the main channel, and the first shunt channel is linear; The second inlet end (91) of the second branch channel is connected to the lower right side of the main channel and is located downstream of the outlet end of the first branch channel, and the second outlet end (92) of the second branch channel is connected to the main channel. On the right side and upstream of the outlet end of the first split channel, the second split channel is in a fan shape greater than 180°, and the first split channel and the second split channel are located in different planes.

Further, the polar coordinate equation of the first heart-shaped function curve (6) is: r ₁ =a ₁ ·(1+cosθ), and the polar coordinate equation of the second heart-shaped function curve (7) is: r ₂ = a ₂ ·(1+cosθ), where the value of parameter a determines the degree of curvature of the heart-shaped function curve. The greater the value of a, the greater the curvature; a is a constant that is always greater than zero, and the value range of θ is 0 to π, in order to ensure that the overall channel profile of the cardioid function micromixer unit shows a continuous contraction and expansion trend, the values of a ₁ and a ₂ must satisfy: a ₁ > a ₂ , and 5μm ≤ _{a 1} -a ₂ ≤ 15 μm; r ₁ > 0, r ₂ > 0, the main channel curve of the cardioid function micromixer unit is symmetrical to the main channel curve of the next adjacent cardioid function micromixer unit about the midpoint of their connection.

Further, the micromixer unit group (M) includes four, six or eight cardioid function micromixer units (5) smoothly connected end to end, and the third of each cardioid function micromixer unit is An inlet end (51) and a first outlet end (52) are both located on the central axis (X-X); the first fluid inlet channel and the second fluid inlet channel are arranged collinearly at an angle of 180°, and the preliminary mixing channel (3) The side contour line is set in line with the central axis, and the lower side outline line of the outlet channel (4) is set in line with the central axis; the heart-shaped function micromixer unit (5) located on the upper side of the central axis (X-X) includes a main channel, The first split channel (8), the second split channel (8), and the heart-shaped function micromixer unit located on the lower side of the central axis include a main channel and a second split channel.

Further, the cardioid function micromixer unit (5) also includes a micro-concave-convex corrugated portion (71), the micro-concave-convex corrugated portion is disposed at the upstream portion of the second heart-shaped function curve (7), and the micro-concave-convex corrugated portion extends from The first inlet end (51) extends to the inlet end of the first branch channel (8).

Furthermore, the micro-concave and convex corrugated portion (71) has two or more sections of corrugated structures with different pitches, and the pitch of the corrugated section located on the side of the first inlet end (51) is smaller than that of the section located on the inlet end of the first shunt channel (8). The pitch of the corrugated section on the side.

Further, a pressure accumulation chamber (81) is provided in the middle or left side of the first shunt channel (8), and the pressure accumulation chamber is circular.

Further, after the fluid in the first branch channel (8) flows out through the outlet end and is reflected by the wall of the first heart-shaped function curve (6), part of the fluid flows back to the position roughly corresponding to the second inlet end (91). Second shunt channel (9).

Further, the second branch channel (9) of the first cardioid function micromixer unit (5) and the second branch channel (9) of the second cardioid function micromixer unit are arranged with respect to the first outlet end (52) The midpoint of the second heart-shaped function micromixer unit is symmetrically arranged, and the inlet end of the second branch channel of the second cardioid function micromixer unit is located on the downstream side of the outlet end.

Further, the concave and convex corrugated portion (71) of the first cardioid function micromixer unit (5) and the concave and convex corrugated portion of the second cardioid function micromixer unit are aligned with each other with respect to the center of the first outlet end (52). Point-center symmetry is provided; the widths of the first fluid inlet channel, the second fluid inlet channel, the preliminary mixing channel, and the outlet channel are all consistent and larger than the cross-sectional widths of the first shunt channel (8) and the second shunt channel (9).

Further, the width of the first inlet end (51) is 1.2-1.6 times the width of the first outlet end (52), and the width of the first outlet end is 1.8-2.2 times the width of the second shunt channel (9). The angle between a branch channel (8) and the central axis (X-X) is 13-17°.

The present invention is a passive micromixer with a heart-shaped function structure. Two heart-shaped functions with different curvatures form a special channel structure that contracts and expands, causing the fluid (liquid) to appear secondary flows and vortices of different scales in the main channel. , at the same time, the splitting channels (the first splitting channel and/or the second splitting channel) cause the fluids to continuously split and merge, which intensifies the unbalanced collision between the fluids, generates chaotic convection and vortex, and vortex-induced mixing flow, improves the mixing intensity, and shortens the The length of the flow channel reduces the mixing time and improves the mixing effect. Through the arrangement of the concave and convex corrugated parts, the boundary laminar flow liquid in the main channel can be promoted to flow into the first branch channel, so that the liquid in the first branch channel has a certain flow rate and flow speed, thereby improving jet flow, chaotic convection, and vortex flow. Stirring effect.

Description of the drawings

Figure 1 is a schematic structural diagram of a passive micromixer with a heart-shaped functional structure of the present invention;

Figure 2 is a partial structural schematic diagram of a passive micromixer with a heart-shaped functional structure of the present invention;

Figure 3 is a partial structural schematic diagram of a passive micromixer with a heart-shaped functional structure of the present invention.

In the figure: the first fluid inlet channel 1, the second fluid inlet channel 2, the preliminary mixing channel 3, the outlet channel 4, (the first of the cardioid function structure mixing unit) micro mixer unit 5, the first cardioid function curve 6. The second heart-shaped function curve 7, the first shunt channel 8, the second shunt channel 9, the first inlet end 51, the first outlet end 52, the slightly concave and convex corrugated portion 71, the pressure accumulation chamber 81, and the second inlet end 91 , the second outlet end 92; micro mixer unit group M, central axis X-X.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention.

The present invention will be further described in detail below in conjunction with the accompanying drawings.

As shown in Figure 1-3, a passive micromixer with a heart-shaped functional structure includes a first fluid inlet channel 1, a second fluid inlet channel 2, a preliminary mixing channel 3, a micromixer unit group M, and an outlet channel. 4. The first fluid inlet channel 1 and the second fluid inlet channel 2 are both connected to the preliminary mixing channel 3. The micromixer unit group M includes a plurality of heart-shaped function micromixer units 5 that are smoothly connected end to end. The micromixer unit The downstream end of the unit group M is connected to the outlet channel 4, the downstream end of the preliminary mixing channel 3 is connected to the first inlet end 51 of the cardioid function micromixer unit 5, and the first outlet of the cardioid function micromixer unit 5 End 52 is connected to the first inlet end 51 of the next cardioid function micromixer unit 5. The combined channel formed by the main channels of the first and second cardioid function micromixer units 5 first gradually shrinks and then gradually Expanded structure; characterized in that: the heart-shaped function micromixer unit 5 includes a main channel, a first branch channel 8, and a second branch channel 9. The main channel is composed of a first heart-shaped function curve 6, a second heart-shaped function curve 7, the inlet end of the first branch channel 8 is connected to the upper left side of the main channel, the outlet end of the first branch channel 8 is connected to the lower right side of the main channel, the first branch channel 8 is linear, and the second branch channel 8 is linear. The second inlet end 91 of the channel 9 is connected to the lower right side of the main channel and is located downstream of the outlet end of the first branch channel 8. The second outlet end 92 of the second branch channel 9 is connected to the right side of the main channel and is located at Upstream of the outlet end of the first split channel 8, the second split channel 9 has a fan-shaped/arc shape greater than 180° (preferably greater than 245°), and the first split channel 8 and the second split channel 9 are located in different planes (such as The first branch channel 8 is located in a plane above or below the second branch channel 9).

The polar coordinate equation of the first heart-shaped function curve 6 is: r ₁ =a ₁ ·(1+cosθ), and the polar coordinate equation of the second heart-shaped function curve 7 is: r ₂ =a ₂ ·(1+cosθ), The value of parameter a determines the degree of curvature of the heart-shaped function curve. The greater the value of a, the greater the curvature. In this embodiment, a is a constant greater than zero, and the value range of θ is from 0 to π. In order to ensure that the overall channel profile of the cardioid function micromixer unit 5 shows a continuous contraction and expansion trend, a ₁ and a ₂ The value must satisfy: a ₁ > a ₂ , and 5μm ≤ _{a 1} -a ₂ ≤ 15μm; r ₁ > 0, r ₂ > 0, the main channel curve (6,7) of the cardioid function micromixer unit 5 and its The main channel curve of the adjacent next cardioid function micromixer unit 5 is centrally symmetrical about the midpoint (π, (a ₁ +a ₂ ) (1+cosθ)/2) of their connection.

In this embodiment, the micromixer unit group M includes six cardioid function micromixer units 5 that are smoothly connected end to end. Of course, it can also be less than or greater than six. The third of each cardioid function micromixer unit 5 An inlet end 51 and a first outlet end 52 are both located on the central axis X-X is set in line, and the lower side outline of the exit channel 4 is set in line with the central axis X-X.

The heart-shaped function micromixer units 5 (i.e., the 1st, 3rd, 5th, 7th...) located on the upper side of the central axis X-X each include a main channel, a first branch channel 8, and a second branch channel 9. The heart-shaped function micromixer units 5 (i.e., the 2nd, 4th, 6th, 8th...) located on the lower side of the central axis X-X each include a main channel and a second branch channel 9.

In one embodiment, the cardioid function micromixer unit 5 further includes a micro-concave-convex corrugated portion 71 , the micro-concave-convex corrugated portion 71 is disposed at the upstream portion of the second heart-shaped function curve 7 , and the micro-concave-convex corrugated portion 71 exits from the first inlet. The end 51 extends to the inlet end of the first branch channel 8 .

Furthermore, the micro-concave-convex corrugated portion 71 has two or more sections of corrugated structures with different pitches. The pitch of the corrugated section located on the side of the first inlet end 51 is smaller than the pitch of the corrugated section located on the side of the inlet end of the first branch channel 8 .

A pressure accumulation chamber 81 is provided in the middle or left side of the first shunt channel 8 , and the pressure accumulation chamber 81 is circular.

Furthermore, after the fluid in the first branch channel 8 flows out through the outlet end and is reflected by the wall of the first heart-shaped function curve 6 , part of the fluid flows back to the second branch channel 9 at a position roughly corresponding to the second inlet end 91 .

The second branching channel 9 of the first cardioid function micromixer unit 5 and the second branching channel 9 of the second cardioid function micromixer unit 5 are arranged symmetrically with respect to the center of the midpoint of the first outlet end 52, and the second The inlet end of the second branch channel 9 of the cardioid function micromixer unit 5 is located on the downstream side of the outlet end.

The concave and convex corrugated portions 71 of the first cardioid function micromixer unit 5 and the concave and convex corrugated portions 71 of the second cardioid function micromixer unit 5 are arranged symmetrically about the center of the midpoint of the first outlet end 52 .

The widths of the first fluid inlet channel 1 , the second fluid inlet channel 2 , the preliminary mixing channel 3 , and the outlet channel 4 are all consistent and larger than the cross-sectional widths of the first branch channel 8 and the second branch channel 9 .

The width of the first inlet end 51 is 1.2-1.6 times (preferably 1.4 times) the width of the first outlet end 52 , and the width of the first outlet end 52 is 1.8-2.2 times (preferably 2.0 times) the width of the second branch channel 9 ), the angle between the first branch channel 8 and the central axis X-X is 13-17° (preferably 15°).

The working principle of a passive micromixer with a heart-shaped functional structure of the present invention is:

Two different fluids (liquids) flow into the preliminary mixing channel 3 through the first fluid inlet channel 1 and the second fluid inlet channel 2 respectively to complete the initial mixing, and then flow into the heart-shaped function micromixer unit 5 from the preliminary mixing channel 3. The fluid enters the heart. After the shape function micromixer unit has 5 channels, the flow trajectory of the fluid changes, and centrifugal force is generated under the action of the heart-shaped curve channel, which in turn causes the fluid to generate a radial velocity gradient. The fluid generates secondary flow and flow under the special channel structure of contraction and expansion. Vortices of different scales increase the contact area between the two fluids. At the same time, each heart-shaped function micromixer unit 5 is provided with a first split channel 8 and/or a second split channel 9. The fluids are continuously split and merged in the channel. The narrow split channel can produce a jet effect and create chaos among the fluids. Convection and vortex mixed flow make the two different fluids mix more fully and evenly. After several contraction and expansion micromixer units, the mixing process is completed, and the liquid that has reached a better/higher mixing degree flows out from the outlet channel 4 , shortening the flow channel length, reducing mixing time and improving mixing effect.

Through the arrangement of the concave and convex corrugated portions 71, the boundary laminar flow liquid in the main channel can be promoted to flow into the first branch channel 8, so that the liquid in the first branch channel 8 has a certain flow rate and flow speed, thereby improving jet flow and chaos. Convection and vortex induced mixed flow effects.

The present invention is a passive micromixer with a heart-shaped function structure. Two heart-shaped functions with different curvatures form a special channel structure that contracts and expands, causing the fluid (liquid) to appear secondary flows and vortices of different scales in the main channel. , at the same time, the splitting channels (the first splitting channel and/or the second splitting channel) cause the fluids to continuously split and merge, which intensifies the unbalanced collision between the fluids, generates chaotic convection and vortex, and vortex-induced mixing flow, improves the mixing intensity, and shortens the The length of the flow channel reduces the mixing time and improves the mixing effect.

It should be noted that all directional indications (such as up, down, left, right, front, back, horizontal, vertical, etc.) in the embodiments of the present invention are only used to explain each direction in a specific posture (as shown in the accompanying drawings). The relative positional relationship between components, movement conditions, etc., if the specific posture changes, the directional indication will also change accordingly. The "connection" can be a direct connection or an indirect connection, so The "set", "set on" and "set on" mentioned above may be directly set on, or may be indirectly set on.

The above-mentioned embodiments are illustrative of the present invention, not limitations of the present invention. It can be understood that various changes, modifications, substitutions and modifications can be made to these embodiments without departing from the principles and spirit of the present invention. The protection scope of the present invention as defined by the appended claims and their equivalents.

Claims (10)

1. The passive micromixer with the heart-shaped function structure comprises a first fluid inlet channel (1), a second fluid inlet channel (2), a primary mixing channel (3), a micromixer unit group (M) and an outlet channel (4), wherein the first fluid inlet channel and the second fluid inlet channel are connected with the primary mixing channel, the micromixer unit group comprises a plurality of heart-shaped function micromixer units (5) which are sequentially and smoothly connected end to end, the downstream end of the micromixer unit group is connected with the outlet channel, the downstream end of the primary mixing channel is connected with a first inlet end (51) of the heart-shaped function micromixer unit, a first outlet end (52) of the heart-shaped function micromixer unit is connected with a first inlet end of the next heart-shaped function micromixer unit, and a combined channel formed by main channels of the first heart-shaped function micromixer unit and the second heart-shaped function micromixer unit is in a structure that the combined channel is gradually contracted and then gradually expanded;

the method is characterized in that: the heart-shaped function micromixer unit (5) comprises a main channel, a first flow distribution channel (8) and a second flow distribution channel (9), wherein the main channel consists of a first heart-shaped function curve (6) and a second heart-shaped function curve (7), the inlet end of the first flow distribution channel is connected to the left upper side of the main channel, the outlet end of the first flow distribution channel is connected to the right lower side of the main channel, and the first flow distribution channel is linear; the second inlet end (91) of the second diversion channel is connected to the right lower side of the main channel and is positioned at the downstream of the outlet end of the first diversion channel, the second outlet end (92) of the second diversion channel is connected to the right side of the main channel and is positioned at the upstream of the outlet end of the first diversion channel, the second diversion channel is in a fan shape of more than 180 degrees, and the first diversion channel and the second diversion channel are positioned in different planes.

2. A passive micromixer of a cardioid structure according to claim 1, characterized in that the polar equation of the first cardioid curve (6) is: r is (r) ₁ ＝a ₁ The polar equation for the second cardioid curve (7) is: r is (r) ₂ ＝a ₂ (1+cos θ), wherein the value of parameter a determines the magnitude of the curve of the heart function, the larger the value of a, the larger the curve; a is a constant which is constantly larger than zero, the value range of theta is 0 to pi, and in order to ensure that the integral channel profile of the heart-shaped function micromixer unit presents continuous shrinkage and expansion trend, a ₁ And a ₂ The value of (2) must satisfy: a, a ₁ ＞a ₂ And a is more than or equal to 5 mu m ₁ -a ₂ ≤15μm；r ₁ ＞0，r ₂ > 0, the main channel curve of a cardioid micromixer unit and the main channel curve of the next cardioid micromixer unit adjacent thereto are about the midpoint of their junctionAnd the centers are symmetrical.

3. A passive micromixer of a cardioid structure according to claim 2, wherein the set (M) of micromixer units comprises four, six or eight cardioid micromixer units (5) connected end to end in a smooth sequence, each cardioid micromixer unit having a first inlet end (51), a first outlet end (52) located on a central axis (X-X); the first fluid inlet channel and the second fluid inlet channel are arranged in a collinear way to form an included angle of 180 degrees, the contour line of the upper side of the primary mixing channel (3) is arranged in a collinear way with the central axis, and the contour line of the lower side of the outlet channel (4) is arranged in a collinear way with the central axis; the heart-shaped function micro-mixer units (5) positioned on the upper side of the central axis (X-X) comprise a main channel, a first diversion channel (8) and a second diversion channel (8), and the heart-shaped function micro-mixer units positioned on the lower side of the central axis comprise the main channel and the second diversion channel.

4. A passive micromixer of a cardioid function configuration according to claim 1, wherein the cardioid function micromixer unit (5) further comprises a micro-relief corrugation (71) arranged at an upstream portion of the second cardioid function curve (7), and the micro-relief corrugation extends from the first inlet end (51) to the inlet end of the first shunt channel (8).

5. A passive micromixer having a cardioid function according to claim 4, wherein the micro-concave-convex corrugation (71) has a corrugation structure of two or more different pitches, and the pitch of the corrugation located on the side of the first inlet end (51) is smaller than that of the corrugation located on the side of the inlet end of the first distribution channel (8).

6. A passive micromixer of a cardioid structure according to claim 5, characterized in that the first shunt channel (8) is provided with a pressure accumulation chamber (81) in the middle or left position, which is circular.

7. A passive micromixer according to claim 6, wherein the fluid in the first flow distribution channel (8) flows out through the outlet end and then flows back to the second flow distribution channel (9) at a position substantially corresponding to the second inlet end (91) after being reflected by the wall of the first cardioid curve (6).

8. A passive micromixer of a cardioid structure according to claim 7, wherein the second flow diversion channel (9) of the first cardioid micromixer unit (5) is arranged centrally symmetrically to the second flow diversion channel of the second cardioid micromixer unit with respect to the midpoint of the first outlet end (52), the inlet end of the second flow diversion channel of the second cardioid micromixer unit being located downstream of the outlet end.

9. A passive micromixer of cardioid structure according to claim 8, wherein the male and female corrugations (71) of the first cardioid micromixer unit (5) are arranged centrally symmetrically to the male and female corrugations of the second cardioid micromixer unit with respect to the midpoint of the first outlet end (52); the widths of the first fluid inlet channel, the second fluid inlet channel, the preliminary mixing channel and the outlet channel are kept consistent and are larger than the cross-sectional widths of the first diversion channel (8) and the second diversion channel (9).

10. A passive micromixer according to claim 9, wherein the width of the first inlet end (51) is 1.2-1.6 times the width of the first outlet end (52), the width of the first outlet end is 1.8-2.2 times the width of the second flow dividing channel (9), and the angle between the first flow dividing channel (8) and the central axis (X-X) is 13-17 °.