A passive micromixer of cardioid function structure

Abstract

The application discloses a passive micro-mixer with a cardioid function structure, which comprises a first fluid inlet channel (1), a second fluid inlet channel (2), a preliminary mixing channel (3), a micro-mixer unit group (M), and an outlet channel (4). The micro-mixer unit group comprises a plurality of cardioid function micro-mixer units (5) which are sequentially and smoothly connected in a head-to-tail mode. The combined channel formed by the main channels of the first and second cardioid function micro-mixer units has a structure of gradually shrinking first and then gradually expanding. The cardioid function micro-mixer unit comprises a main channel, a first branch channel (8) and a second branch channel (9). The application causes the fluid to generate secondary flow and different scale vortices in the main channel, and the branch channels continuously branch and converge the fluid, intensify the unbalanced collision between the fluids, generate chaotic convection and vortex-induced mixing flow, improve the mixing strength, shorten the flow path length, reduce the mixing time, and improve the mixing effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of microfluidic mixing, in particular to a passive micro-mixer with a cardioid function structure. BACKGROUND

[0002] Microfluidic chip technology can operate separation, sample addition, mixing, reaction, detection and other functions in the laboratory analysis and detection process in the micron scale space, so the microfluidic chip is also called chip laboratory. The microfluidic mixer is one of the important components of the microfluidic chip. The closed microchannel and chamber can isolate the contact between the person and the reagent, ensuring the safety of the personnel while preventing the reagent from being contaminated. Compared with the macroscopic mixer, the microfluidic mixer has the advantages of high heat transfer efficiency, high speed mixing, rapid system response and high safety performance, and is widely used in medicine, chemical industry, food and other fields.

[0003] At present, according to whether external energy needs to be introduced to enhance the mixing effect, the microfluidic mixer is divided into active micro-mixer and passive micro-mixer. The active micro-mixer needs external power in addition to the energy of pumping fluid, such as sound field, electric field, magnetic fluid power field, mechanical stirring, etc. to realize the disturbance of the fluid in the microchannel to achieve the expected mixing effect. The active micro-mixer is difficult to manufacture and has high processing cost. The driving of sound field, electric field, etc. will generate heat, which may cause unnecessary side reactions of the reagent. The passive micro-mixer does not need external energy driving in addition to the energy of pumping fluid, mainly relying on special geometric channels to promote fluid mixing, such as converging-diverging structure, stretching-folding structure, setting obstacles in the channel, etc. Its advantages are simple structure, easy to process and integrate; the disadvantage is that a longer mixing channel is needed, the mixing speed is relatively slow, and the mixing time is relatively long.

[0004] For example, the prior art discloses passive microfluidic mixers including "snake type", "S type" and other forms of micro-mixers. The fluid channel cross-sectional area of each micro-mixer unit can be equal, gradually reduced or gradually increased. However, the existing micro-mixer still has the problems of relatively slow mixing speed and relatively long mixing time. SUMMARY

[0005] The purpose of the present application is to overcome the deficiencies in the prior art, provide a passive micro-mixer with a cardioid function structure, and two cardioids with different curvatures constitute a special channel structure of contraction and expansion, so that the fluid (liquid) appears secondary flow and different scale vortexes in the main channel, while the branch channels (first branch channel and / or second branch channel) make the fluid continuously branch and converge, intensify the imbalance collision between the fluids, produce chaotic convection and vortex, vortex-induced mixing flow, improve the mixing strength, shorten the flow path length, reduce the mixing time and improve the mixing effect.

[0006] To achieve the above object, the technical scheme adopted by the present application is:

[0007] A passive micro-mixer of cardioid function structure comprises a first fluid inlet channel (1), a second fluid inlet channel (2), a preliminary mixing channel (3), a micro-mixer unit group (M), an outlet channel (4), the first fluid inlet channel and the second fluid inlet channel are connected with the preliminary mixing channel, the micro-mixer unit group comprises a plurality of cardioid function micro-mixer units (5) which are sequentially and smoothly connected in a head-to-tail manner, the downstream end of the micro-mixer unit group is connected with the outlet channel, the downstream end of the preliminary mixing channel is connected with the first inlet end (51) of the cardioid function micro-mixer unit, the first outlet end (52) of the cardioid function micro-mixer unit is connected with the first inlet end of the next cardioid function micro-mixer unit, and the combined channel formed by the main channels of the first and second cardioid function micro-mixer units has a structure of gradually shrinking first and then gradually expanding; characterized in that the cardioid function micro-mixer unit (5) comprises a main channel, a first shunt channel (8) and a second shunt channel (9), the main channel is composed of a first cardioid function curve (6) and a second cardioid 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 in a straight line type; the second inlet end (91) of the second shunt channel is connected to the lower right side of the main channel and is located downstream of the outlet end of the first shunt channel, the second outlet end (92) of the second shunt channel is connected to the right side of the main channel and is located upstream of the outlet end of the first shunt channel, the second shunt channel is in a sector shape greater than 180°, and the first shunt channel and the second shunt channel are located in different planes.

[0008] Further, the polar coordinate equation of the first cardioid function curve (6) is r1=a1·(1+cosθ), and the polar coordinate equation of the second cardioid function curve (7) is r2=a2·(1+cosθ), wherein the value of the parameter a determines the bending degree of the cardioid function curve, the greater the value of a, the greater the bending degree; a is a constant greater than zero, the value range of θ is 0 to π, in order to ensure that the overall channel profile of the cardioid function micro-mixer unit presents a continuous shrinking and expanding trend, the values of a1 and a2 must satisfy a1>a2 and 5μm≤a1-a2≤15μm; r1>0 and r2>0, and the main channel curve of the cardioid function micro-mixer unit and the main channel curve of the next cardioid function micro-mixer unit adjacent thereto are centrally symmetric about the midpoint of their connection.

[0009] Further, the micro-mixer unit group (M) comprises four, six or eight heart function micro-mixer units (5) connected in sequence, the first inlet end (51) and the first outlet end (52) of each heart function micro-mixer unit are located on the central axis (X-X); the first fluid inlet channel and the second fluid inlet channel are arranged in a 180° angle, the upper profile line of the preliminary mixing channel (3) is arranged in line with the central axis, and the lower profile line of the outlet channel (4) is arranged in line with the central axis; the heart function micro-mixer units (5) located on the upper side of the central axis (X-X) each comprise a main channel, a first branch channel (8) and a second branch channel (8), and the heart function micro-mixer units located on the lower side of the central axis each comprise a main channel and a second branch channel.

[0010] Further, the heart function micro-mixer unit (5) further comprises a micro concave-convex corrugated portion (71), which is arranged at the upstream portion of the second heart function curve (7) and extends from the first inlet end (51) to the inlet end of the first branch channel (8).

[0011] Further, the micro concave-convex corrugated portion (71) has a corrugated structure with two or more segments of different pitches, and the pitch of the corrugated segment located on the side of the first inlet end (51) is smaller than the pitch of the corrugated segment located on the side of the inlet end of the first branch channel (8).

[0012] Further, the first branch channel (8) is provided with a pressure accumulation cavity (81) at the middle or left side position, and the pressure accumulation cavity is circular.

[0013] Further, after the fluid in the first branch channel (8) flows out through the outlet end and is reflected by the wall portion of the first heart function curve (6), part of the fluid flows back to the second branch channel (9) approximately corresponding to the position of the second inlet end (91).

[0014] Further, the second branch channel (9) of the first heart function micro-mixer unit (5) is arranged in central symmetry with the second branch channel of the second heart function micro-mixer unit about the midpoint of the first outlet end (52), and the inlet end of the second branch channel of the second heart function micro-mixer unit is located on the downstream side of the outlet end.

[0015] Further, the concave-convex corrugated portion (71) of the first heart function micro-mixer unit (5) is arranged in central symmetry with the concave-convex corrugated portion of the second heart function micro-mixer unit about 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 consistent and greater than the cross-sectional widths of the first branch channel (8) and the second branch channel (9).

[0016] Further, 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 branch channel (9), and the included angle between the first branch channel (8) and the central axis (X-X) is 13-17°.

[0017] The passive micro-mixer with the heart-shaped function structure of the application comprises a special channel structure formed by the heart-shaped functions with different curvatures, so that secondary flow and different scale vortices of the fluid (liquid) appear in the main channel, the branch channels (the first branch channel and / or the second branch channel) make the fluid continuously branch and converge, the imbalance collision between the fluids is intensified, chaotic convection and vortex-induced mixing flow are generated, the mixing strength is improved, the flow path length is shortened, the mixing time is reduced, and the mixing effect is improved. Through the setting of the concave-convex corrugated part, the boundary layer flow liquid in the main channel can flow into the first branch channel, so that the liquid in the first branch channel has a certain flow and flow rate, thereby improving the jet, chaotic convection and vortex-induced mixing flow effect. BRIEF DESCRIPTION OF DRAWINGS

[0018] Fig. 1 The figure is a structural schematic diagram of the passive micro-mixer with the heart-shaped function structure of the application.

[0019] Fig. 2 The figure is a structural schematic diagram of the passive micro-mixer with the heart-shaped function structure of the application.

[0020] Fig. 3 The figure is a structural schematic diagram of the passive micro-mixer with the heart-shaped function structure of the application.

[0021] 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 micro-mixer unit (the first one of the heart-shaped function structure mixing unit) 5, the first heart-shaped function curve 6, the second heart-shaped function curve 7, the first branch channel 8, the second branch channel 9, the first inlet end 51, the first outlet end 52, the micro-concave-convex corrugated part 71, the pressure accumulation cavity 81, the second inlet end 91, the second outlet end 92, the micro-mixer unit group M, and the central axis X-X. DETAILED DESCRIPTION

[0022] To make the purpose, technical scheme and advantages of the embodiments of the application clearer, the technical scheme in the embodiments of the application will be described clearly and completely below in combination with the drawings in the embodiments of the application. Obviously, the described embodiments are some embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0023] The application will be further described in detail below with reference to the accompanying drawings.

[0024] As Figs. 1-3 shown in the figure, a passive micro-mixer of cardioid function structure includes a first fluid inlet channel 1, a second fluid inlet channel 2, a preliminary mixing channel 3, a micro-mixer unit group M, an outlet channel 4, the first fluid inlet channel 1 and the second fluid inlet channel 2 are connected with the preliminary mixing channel 3, the micro-mixer unit group M includes a plurality of cardioid function micro-mixer units 5 which are sequentially and smoothly connected in head-to-tail mode, the downstream end of the micro-mixer unit group M is connected with the outlet channel 4, the downstream end of the preliminary mixing channel 3 is connected with the first inlet end 51 of the cardioid function micro-mixer unit 5, the first outlet end 52 of the cardioid function micro-mixer unit 5 is connected with the first inlet end 51 of the next cardioid function micro-mixer unit 5, the combined channel formed by the main channels of the first and second cardioid function micro-mixer units 5 has a structure of gradually shrinking first and then gradually expanding; characterized in that: the cardioid function micro-mixer unit 5 includes a main channel, a first shunt channel 8 and a second shunt channel 9, the main channel is composed of a first cardioid function curve 6 and a second cardioid function curve 7, the inlet end of the first shunt channel 8 is connected to the upper left side of the main channel, the outlet end of the first shunt channel 8 is connected to the lower right side of the main channel, the first shunt channel 8 is in a straight line type, the second inlet end 91 of the second shunt channel 9 is connected to the lower right side of the main channel and is located downstream of the outlet end of the first shunt channel 8, the second outlet end 92 of the second shunt channel 9 is connected to the right side of the main channel and is located upstream of the outlet end of the first shunt channel 8, the second shunt channel 9 is in a sector / arc shape greater than 180° (preferably greater than 245°), the first shunt channel 8 and the second shunt channel 9 are located in different planes (such as the first shunt channel 8 is located in the plane above or below the second shunt channel 9).

[0025] The polar equation of the first cardioid function curve 6 is r1=a1·(1+cosθ), and the polar equation of the second cardioid function curve 7 is r2=a2·(1+cosθ), wherein the value of the parameter a determines the bending degree of the cardioid function curve, the greater the value of a, the greater the bending degree. In this embodiment, a is a constant greater than zero, the value range of θ is 0 to π, in order to ensure that the overall channel profile of the cardioid function micro-mixer unit 5 presents a continuous shrinking and expanding trend, the value of a1 and a2 must satisfy: a1>a2, and 5μm≤a1-a2≤15μm; r1>0, r2>0, the main channel curve (6, 7) of the cardioid function micro-mixer unit 5 and the main channel curve of the next cardioid function micro-mixer unit 5 adjacent thereto are centrally symmetric about the midpoint (π, (a1+a2)(1+cosθ) / 2) of their connection.

[0026] In this embodiment, the micro-mixer unit group M includes six heart function micro-mixer units 5 connected in sequence, of course, it can be less than or greater than six, the first inlet end 51 and the first outlet end 52 of each heart function micro-mixer unit 5 are located on the center axis X-X; the first fluid inlet channel 1 and the second fluid inlet channel 2 are arranged in a 180° angle, the upper profile line of the preliminary mixing channel 3 is arranged in line with the center axis X-X, and the lower profile line of the outlet channel 4 is arranged in line with the center axis X-X.

[0027] The heart function micro-mixer units 5 located on the upper side of the center axis X-X (i.e. the 1st, 3rd, 5th, 7th, …) each include a main channel, a first branch channel 8, and a second branch channel 9, and the heart function micro-mixer units 5 located on the lower side of the center axis X-X (i.e. the 2nd, 4th, 6th, 8th, …) each include a main channel and a second branch channel 9.

[0028] In an embodiment, the heart function micro-mixer unit 5 further includes a micro concave-convex corrugated part 71, which is arranged at the upstream part of the second heart function curve 7 and extends from the first inlet end 51 to the inlet end of the first branch channel 8.

[0029] Further, the micro concave-convex corrugated part 71 has a corrugated structure with two or more segments of different pitches, and the pitch of the corrugated segment located on the side of the first inlet end 51 is smaller than the pitch of the corrugated segment located on the side of the inlet end of the first branch channel 8.

[0030] The first branch channel 8 is provided with a pressure accumulation cavity 81 at the middle or left side position, and the pressure accumulation cavity 81 is circular.

[0031] Further, after the fluid in the first branch channel 8 flows out through the outlet end and is reflected by the wall part of the first heart function curve 6, part of the fluid flows back to the second branch channel 9 approximately corresponding to the position of the second inlet end 91.

[0032] The second branch channel 9 of the first heart function micro-mixer unit 5 and the second branch channel 9 of the second heart function micro-mixer unit 5 are arranged in central symmetry about the midpoint of the first outlet end 52, and the inlet end of the second branch channel 9 of the second heart function micro-mixer unit 5 is located on the downstream side of the outlet end.

[0033] The concave-convex corrugated part 71 of the first heart function micro-mixer unit 5 and the concave-convex corrugated part 71 of the second heart function micro-mixer unit 5 are arranged in central symmetry about the midpoint of the first outlet end 52.

[0034] 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 consistent and greater than the cross-sectional width of the first branch channel 8 and the second branch channel 9.

[0035] 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, 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, and the included angle between the first branch channel 8 and the central axis X-X is 13-17° (preferably 15°).

[0036] The working principle of the passive micromixer with a cardioid function structure is as follows:

[0037] 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 initial mixing, and then flow into the cardioid function micromixer unit 5 from the preliminary mixing channel 3. After the fluids enter the channel of the cardioid function micromixer unit 5, the flow trajectory of the fluids changes, centrifugal force is generated under the action of the cardioid curve channel, and radial velocity gradient is generated, and secondary flow and vortices of different scales are generated under the special channel structure of contraction and expansion, so that the contact area between the two fluids is increased. At the same time, the first branch channel 8 and / or the second branch channel 9 are arranged in each cardioid function micromixer unit 5, the fluids continuously branch and converge in the channel, the narrow branch channel can produce jet effect, chaotic convection and vortex-induced mixing are generated between the fluids, so that the two different fluids are mixed more fully and uniformly, and after passing through several contraction and expansion micromixer units, the mixing process is completed, the liquid with a good / high mixing degree flows out from the outlet channel 4, the flow path length is shortened, and the mixing time is reduced and the mixing effect is improved.

[0038] Through the arrangement of the concave-convex corrugated part 71, the boundary layer 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 the jet, chaotic convection and vortex-induced mixing effect.

[0039] The passive micromixer with a cardioid function structure of the application comprises two cardioid functions with different curvatures, which constitute a special channel structure of contraction and expansion, so that secondary flow and vortices of different scales appear in the fluids (liquids) in the main channel, and the branch channels (the first branch channel and / or the second branch channel) make the fluids continuously branch and converge, intensify the unbalanced collision between the fluids, generate chaotic convection and vortex-induced mixing, improve the mixing strength, shorten the flow path length, reduce the mixing time and improve the mixing effect.

[0040] It should be noted that all the direction indications (such as up, down, left, right, front, back, horizontal, vertical, etc.) in the embodiments of the present application are only used to explain the relative position relationship, motion condition, etc. between the components in a certain specific posture (as shown in the drawings), and if the specific posture changes, the direction indications also change accordingly. The "connection" can be direct connection or indirect connection, and the "setting", "set in" and "provided in" can be direct setting or indirect setting.

[0041] The above embodiments are illustrative of the present application, but not a limitation of the present application. It can be understood that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the present application, and the protection scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A passive micromixer of cardioid function structure, comprising a first fluid inlet channel (1), a second fluid inlet channel (2), a preliminary mixing channel (3), a micromixer unit group, an outlet channel (4), the first fluid inlet channel and the second fluid inlet channel being connected with the preliminary mixing channel, the micromixer unit group comprising a plurality of cardioid function micromixer units (5) which are sequentially and smoothly connected in a head-to-tail manner, the downstream end of the micromixer unit group being connected with the outlet channel, the downstream end of the preliminary mixing channel being connected with a first inlet end (51) of the cardioid function micromixer unit, a first outlet end (52) of the cardioid function micromixer unit being connected with a first inlet end of a next cardioid function micromixer unit, the combined channel formed by the main channels of the first and second cardioid function micromixer units being of a structure of gradually contracting first and then gradually expanding; characterized in that the cardioid function micromixer unit (5) comprising a main channel, a first shunt channel (8) and a second shunt channel (9), the main channel being formed by a first cardioid function curve (6) and a second cardioid function curve (7), the inlet end of the first shunt channel being connected to the upper left side of the main channel, the outlet end of the first shunt channel being connected to the lower right side of the main channel, the first shunt channel being of a straight line type; the second inlet end (91) of the second shunt channel being connected to the lower right side of the main channel and being located downstream of the outlet end of the first shunt channel, the second outlet end (92) of the second shunt channel being connected to the right side of the main channel and being located upstream of the outlet end of the first shunt channel, the second shunt channel being of a sector shape greater than 180°, the first shunt channel and the second shunt channel being located in different planes; the polar coordinate equation of the first cardioid function curve (6) being r1=a1·(1+cosθ), the polar coordinate equation of the second cardioid function curve (7) being r2=a2·(1+cosθ), wherein the value of the parameter a determines the bending degree of the cardioid function curve, the greater the value of a, the greater the bending degree; a is a constant greater than zero, the value range of θ being 0 to π, in order to ensure that the overall channel profile of the cardioid function micromixer unit presents a continuously contracting and expanding trend, the values of a1 and a2 must satisfy a1>a2 and 5μm≤a1-a2≤15μm; r1>0, r2>0, the main channel curve of the cardioid function micromixer unit and the main channel curve of the next cardioid function micromixer unit being centrally symmetric about the midpoint of their connection; the cardioid function micromixer unit (5) further comprising a micro concave-convex corrugated portion (71), the micro concave-convex corrugated portion being arranged at the upstream portion of the second cardioid function curve (7) and extending from the first inlet end (51) to the inlet end of the first shunt channel (8); the micro concave-convex corrugated portion (71) having a corrugated structure of two or more segments with different pitches, the pitch of the corrugated segment located at the side of the first inlet end (51) being smaller than the pitch of the corrugated segment located at the side of the inlet end of the first shunt channel (8); a pressure accumulation cavity (81) being arranged at the middle or left side of the first shunt channel (8), the pressure accumulation cavity being circular.

2. The passive micromixer of the heart function structure according to claim 1, wherein, The micro-mixer unit group comprises four, six or eight heart function micro-mixer units (5) connected in sequence, the first inlet end (51) and the first outlet end (52) of each heart function micro-mixer unit are located on the central axis (X-X); the first fluid inlet channel and the second fluid inlet channel are arranged at an angle of 180°, the upper profile line of the preliminary mixing channel (3) is arranged in line with the central axis, and the lower profile line of the outlet channel (4) is arranged in line with the central axis; the heart function micro-mixer units (5) located on the upper side of the central axis (X-X) each comprise a main channel, a first branch channel (8) and a second branch channel (9), and the heart function micro-mixer units located on the lower side of the central axis each comprise a main channel and a second branch channel.

3. The passive micromixer of the heart-shaped function structure according to claim 1, wherein, The fluid in the first branch channel (8) flows out through the outlet end, is reflected by the wall part of the first heart function curve (6), and part of the fluid flows back to the second branch channel (9) corresponding to the position of the second inlet end (91).

4. The passive micromixer of the heart-shaped function structure according to claim 3, wherein, The second branch channel (9) of the first heart function micro-mixer unit (5) is arranged in central symmetry with the second branch channel of the second heart function micro-mixer unit about the midpoint of the first outlet end (52), and the inlet end of the second branch channel of the second heart function micro-mixer unit is located on the downstream side of the outlet end.

5. The passive micromixer of the heart-shaped function structure according to claim 4, wherein, The concave-convex corrugated part (71) of the first heart function micro-mixer unit (5) is arranged in central symmetry with the concave-convex corrugated part of the second heart function micro-mixer unit about 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 consistent and greater than the cross-sectional width of the first branch channel (8) and the second branch channel (9).

6. The passive micromixer of the heart-shaped function structure according to claim 5, 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 branch channel (9), and the angle between the first branch channel (8) and the central axis (X-X) is 13-17°.

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