JP2005127864A - Micromixing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To further accelerate the mixture of fluids by increasing the relative interfacial area of the fluids for generating vortex for mixture, and reducing diffusion distance in a microchannel. <P>SOLUTION: A micromixing device has a structure for generating a volume change periodically in the channel space of an outlet channel 2 in one of the upstream and downstream of a projection 3 by providing the projection 3 in the outlet channel 2. The outlet channel 2 has channel resistance for generating vortex at both the sides of the upstream and downstream in the projection 3 by the periodical volume change in the channel space of the outlet channel 2. The periodical volume change in the channel space of the outlet channel 2 is caused by partial or entire displacement in a channel wall for orthogonally crossing the direction of the flow of the fluid. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a micromixing device for mixing a plurality of fluids in a microchannel (microchannel).

Conventionally, in medical biochemical analysis and chemical analysis, analysis is performed by mixing materials and reagents and reacting them. Conventionally, in performing this mixing and reaction, fluids are brought into contact with each other by a so-called batch system using a tank or the like.
By the way, in order to further increase the contact between fluids, to facilitate mixing and reaction due to diffusion, there is no stagnation of fluid between mixing containers, to obtain a non-partial uniform reaction, etc. There is a so-called micromixer device that causes a fluid to flow through a microchannel to cause mixing and reaction in the micro container. In this case, as a matter of course, the slow / fast reaction depends on the materials and reagents or conditions, but the materials and reagents can be mixed in a shorter time compared to the batch method. It becomes.
However, a microchannel, that is, a flow path of a micrometer unit, for example, 500 μm or less is a world dominated by the number of ray nozzles of 200 or less, for example, and is a laminar flow dominated world. For this reason, the fluid to be mixed becomes a laminar flow in the microchannel, and the mixing of each fluid mainly involves diffusion at the contact surface, that is, the specific interface area of each fluid.
Under these circumstances, various improvements have been made in order to cope with a high fluid flow velocity or a fast reaction in order to further improve the mixing of the fluid in the microchannel and maintain a laminar flow. There have been various proposals regarding the mixing of fluids in microchannels.
As a typical example of the prior art, for example, in Patent Document 1, vibration is transmitted to a mixing flow path provided in a microchannel in a fluid diffusion direction perpendicular to the fluid flow direction, and the molecular motion of the fluid is changed in the diffusion direction. There is a disclosure of technology that increases and increases the movement of molecules in the diffusion direction at the fluid contact interface.
That is, in the above conventional example, on the premise of the existence of laminar flow, molecular movement in the diffusion direction between the fluids is promoted.
JP 2003-210963 A

However, each of the conventional structures described above is in a microchannel, which is a laminar-dominated fine space, and promotes diffusion by, for example, vibration, and a significant effect on mixing cannot be expected.
In view of the above-mentioned problems, the present invention is a micromixing device that further facilitates fluid mixing by increasing the specific interfacial area of the fluid to be mixed by generating vortices and shortening the diffusion distance in the microchannel. The purpose is to provide.

In order to solve the above-described problems and achieve the object, the invention according to claim 1 is directed to a micromixing device in which a plurality of inlet channels are connected to communicate with a single outlet channel. It has a structure in which a protrusion is provided inside, and a volume change is periodically generated in the flow path space of one of the upstream and downstream outlet flow paths of the protrusion.
The invention according to claim 2 is the invention according to claim 1, wherein the outlet channel causes vortices on both the upstream and downstream sides of the protrusion by a periodic volume change in the channel space of the outlet channel. It has a flow path resistance to be generated.
The invention according to claim 3 is the invention according to claim 1, wherein the periodic volume change in the flow path space of the outlet flow path is caused by a part and all of the flow path wall perpendicular to the fluid flow direction. It is characterized by any displacement.

  According to the invention of the present invention, a protrusion is provided in the outlet channel, and volume change is caused in the channel space of the outlet channel upstream or downstream of the protrusion, thereby expanding the channel and / or During contraction, the fluid flows backward on the upstream side of the protrusion, and an alternating flow change that is accelerated on the downstream side occurs, resulting in a flow vortex upstream and downstream of the protrusion. This vortex increases the specific interface area of the fluid, shortens the diffusion distance, and enables rapid mixing. In this case, not only two types of fluids but also a plurality of types of fluids can be mixed by combining the inlet channels.

Exemplary embodiments of a micromixing device according to the present invention will be explained below in detail with reference to the accompanying drawings.
(Embodiment)
FIG. 1 is a cross-sectional configuration diagram of a micromixing device according to an embodiment of the present invention. In FIG. 1, in this micromixing device (hereinafter referred to as a device), two inlet channels 1 and one outlet channel 2 are coupled to form a Y-shaped microchannel. In the outlet channel 2, one projection 3 is provided so as to protrude from the wall surface at a joining position of two kinds of fluids introduced from each inlet channel 1.
In this case, this device is a micrometer-order fine device and can be formed by an existing semiconductor manufacturing technology (photolithography technology). Further, the protrusion 3 has a structure that protrudes only from one side wall surface of the outlet flow channel 2 in order to make the flow of fluid asymmetric with respect to the width direction of the outlet flow channel 2, and as shown in FIG. In addition, vortices are likely to be generated upstream and downstream of the protrusion 3. Further, the protrusion 3 protrudes in such a direction as to reduce the fluid layer thickness with respect to two types of fluids introduced from the respective inlet channels 1. Further, as shown in FIG. 2, the protrusion 3 has a structure in which the width along the fluid flow direction of the protrusion 3 is as narrow as possible, and the protrusion tip and the flow path wall are formed in order to make it easy to create a vortex upstream or downstream as shown in FIG. It is preferable that the distance between and is as narrow as possible. In this case, when narrowing the gap between the tip of the protrusion and the flow path wall, it is also required to leave a certain distance so as not to increase the flow resistance against the fluid. Therefore, the protrusion amount of the protrusion 3 is determined in consideration of these conditions. Specifically, as shown in FIG. 3, the outlet channel width can be 300 μm, the depth is 120 μm, the projection 3 width is 50 μm, and the distance between the projection tip and the channel wall is 20 μm.
Examples of the fluid introduced from the inlet channel 1 include a liquid, a gas, a solid-liquid mixture in which fine particles such as metal are dispersed in the liquid, and a solid-gas mixture in which fine particles such as metal are dispersed in the gas. And a gas-liquid mixture in which a gas is not dissolved but dispersed in a liquid. Further, for example, the case of two types of fluids includes cases where the chemical composition is different and cases where the temperature, the solid-liquid ratio, and the like are different.
Although FIG. 1 shows an example in which two inlet channels 1 are provided, the present invention can be applied even when two inlet channels 1 exceeding two, for example, three are combined as shown in FIG. Here, it is possible to mix the fluid in the outlet channel 2 for three types of fluid. Compared with the case where three liquids are mixed by connecting a conventional micromixer to obtain a mixture of two liquids in series, it is possible to mix three types of fluids at the same time. can do. Mixing can be applied to only three types and more than one type of fluid.

Now, in the device having the inlet channel 1 and the outlet channel 2 configured as described above, the vibrating wall 4 is disposed immediately downstream of the projection forming position of the outlet channel 2 as shown in FIGS. Is formed. The vibration wall 4 constitutes a flow path wall for causing a volume change in the flow path space, and is displaced in a direction in which the flow path is enlarged and reduced in a direction in which the flow path is reduced by vibration. In this case, the material of the vibration wall 4 can be, for example, PZT using a piezoelectric material, and the vibration to the vibration wall 4 is given by a vibration drive source (not shown) with a frequency of 15000 times / min, for example. Is done. Here, what is necessary is to cause a volume change in the flow path space. For this purpose, for example, only the inner wall of the flow path may be enlarged or reduced, or the flow path itself may be caused by physical vibration from the outside. As a result, the volume of the inner wall of the flow path may be changed. However, since this structure is a fine structure formed on the device, it is necessary to select a material suitable for the fine structure or to provide a vibration driving source, for example, a means for generating a voltage or magnetic field having a frequency corresponding to vibration. There is. 5 and 6 show a state in which the flow path space has undergone a volume change. In FIGS. 5 and 6, the upper diagram (i) shows the enlargement of the flow channel, and the lower diagram (ii) shows the reduction of the flow channel. Each is shown. 5 shows a case where (iii) both side walls of the flow path are enlarged or reduced, and further (iv) a case where all the walls (upper, lower, left and right) of the flow path are enlarged or reduced, and FIG. ) The case where one side wall of the flow path is enlarged or reduced is shown. In addition, various enlargement / reduction patterns can be considered.
By providing the protrusion 3 and generating vibration in this way, the protrusion 3 is provided in the outlet flow path 2 to make it easy to generate vortices, and a volume change is generated by vibration in the flow path space immediately downstream of the protrusion. As a result, a reverse flow of the fluid from the downstream to the upstream occurs, and a vortex is actually generated upstream and downstream of the protrusion. This vortex increases the specific interface area of the fluid to be mixed, shortens the diffusion distance, and leads to further mixing of the fluid.

The description so far has been described as being directly downstream of the protrusion 3 as a portion that causes the volume change of the flow path space. However, generating a backflow of fluid over the lower and upstream sides of the protrusion 3 by expansion and contraction, which is a volume change, occurs in the same manner even if the portion that causes the volume change of the flow path space is located immediately upstream of the protrusion 3. To do. Therefore, the site causing the volume change of the flow path space can be located either upstream or downstream of the protrusion 3.
Further, in the description so far, the protrusion 3 is an asymmetric structure that protrudes from only one side wall surface of the outlet channel 2, but the protrusion 3 is protruded from both side walls of the outlet channel 2 as shown in FIG. 7. You can also. In this case, since the fluid flow does not become asymmetric, the generation of vortices cannot be expected as much as the asymmetric structure that easily generates vortices as shown in FIG. 2, but the fluids can be mixed.
Further, in the description so far, the expansion and contraction of the flow path have been described as the volume change of the flow path space. However, even when only expansion or contraction occurs due to vibration, backflow occurs to some extent, resulting in the generation of vortices upstream of the protrusions and contributing to fluid mixing.
In this way, a vortex is generated upstream of the protrusion 3 due to the volume change of the protrusion 3 and the fluid space, and the specific interface area of the fluid is increased by this vortex and the diffusion distance is shortened, thereby promptly mixing the fluid. Can do.

FIG. 8 to FIG. 11 show the explanation of the experimental situation and the results of vortex generation and mixing in this experiment. In the experiment, as shown in FIG. 8, the flow velocity of the fluid was changed in four stages, the vibration location was changed, and the flow path resistance of the outlet flow path 2 downstream from the protrusion 3 was changed. The flow rate of the fluid is 1 (μl / min), 2 (μl / min), 4 (μl / min), 8 (μl / min), the vibration location is 5 mm downstream from the protrusion 3, 10 mm, 15 mm. The resistance was 5 mm downstream from the protrusion 3, and the channel was opened and the channel was routed as it was. FIG. 9 shows the mixing state when the flow rate of the fluid is changed. In the case of this change in flow velocity, the slower the flow velocity, the longer and larger the vortex will be on the upstream side of the projection, and the faster the flow velocity, the smaller the vortex will be.
FIG. 10 shows a mixed state when the vibration location is changed. When the vibration location is 5 mm from the projection 3, a large vortex is generated upstream of the projection 3, and the vortex generated upstream of the projection 3 decreases as the vibration location is 10 mm and 15 mm away from the projection 3.
FIG. 11 shows a mixed state based on the magnitude of the channel resistance downstream of the protrusion 3. In the upper diagram of FIG. 11, when the flow path is routed as it is and a certain amount of flow resistance exists, a large vortex is formed upstream of the protrusion 3 and the mixed state is good, but the flow path is opened at 5 mm from the protrusion ( When cutting), the vortex upstream of the protrusion 3 is small. This is presumably because the change in volume of the fluid due to vibration is transmitted downstream and there is little backflow upstream.
In this way, the experiment was tried under various conditions. In any case, the mixing on the downstream side of the protrusion 3 was promoted by the presence of the protrusion 3 and the volume change due to vibration.

  As described above, the device according to the present invention is useful as a micromixing apparatus using vibration, and is particularly suitable for an analysis / synthesis flow chip or a chemical analysis apparatus.

It is a section lineblock diagram of an embodiment. It is a figure which shows the generation | occurrence | production state of the vortex by a protrusion. It is a figure which shows the example of a dimension of protrusion. It is a section lineblock diagram of other examples of an embodiment. It is explanatory drawing of the expansion / contraction state of a flow path. It is explanatory drawing of the expansion / contraction state of a flow path. It is explanatory drawing of the expansion / contraction state of a flow path. It is a situation explanatory view of a specific experimental example It is a figure which shows the mixing result at the time of changing a flow rate. It is a figure which shows the mixing result at the time of changing a vibration location. It is a figure which shows the mixing result at the time of changing channel resistance.

Explanation of symbols

1 Inlet channel 2 Outlet channel 3 Projection 4 Vibrating wall

Claims (3)

  In a micromixing device in which a plurality of inlet channels are connected to communicate with one outlet channel, a protrusion is provided in the outlet channel, and the flow of one of the outlet channels upstream or downstream of the protrusion is provided. A micro-mixing device characterized by having a structure that causes a volume change periodically in a road space.   2. The outlet channel according to claim 1, wherein the outlet channel has a channel resistance that causes vortices on both the upstream and downstream sides of the protrusion by a periodic volume change in the channel space of the outlet channel. Micro mixing device.   2. The micromixing according to claim 1, wherein the periodic volume change in the flow path space of the outlet flow path is caused by displacement of any one or all of the flow path walls orthogonal to the fluid flow direction. device.

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