A microfluidic chip for simulating porous media and a manufacturing method thereof

Abstract

The present invention provides a microfluidic chip for simulating a porous medium and a manufacturing method thereof, comprising: a magnetic substrate layer and a main flow channel layer arranged successively from bottom to top; an inlet flow channel and an outlet flow channel are respectively arranged at the front and rear ends of the main flow channel layer; a main flow channel cavity is in the middle of the main flow channel layer, and a porous medium loading port is arranged on one side of the main flow channel layer; porous medium particles are introduced into the main flow channel cavity through the porous medium loading port, and are fixed by the magnetic suction force of the magnetic substrate layer, so as to form a porous medium region in the main flow channel cavity.

Description

Technical Field

[0001] The present invention belongs to the technical field of microfluidic chips, and particularly relates to a microfluidic chip for simulating porous media and a manufacturing method thereof. Background Art

[0002] The statements in this part only provide background technical information related to the present invention, and do not necessarily constitute prior art.

[0003] A porous medium is a combination of a solid skeleton and pores for fluid flow. Many physical and chemical processes in nature and human society, such as groundwater migration, oil and gas accumulation, oil and gas production, irrigation, blood capillary flow, etc., occur in porous media. In addition, porous medium materials such as hydrogels, sponges, and wire meshes also play a key role in fields such as biomedicine, equipment manufacturing, and infrastructure construction. Therefore, it is of great significance to carry out research on porous media and their internal fluid dynamic processes with the help of relevant models.

[0004] Microfluidics is a technology for controlling fluid flow at the microscale, with the characteristics of miniaturization, integration, and automation. Due to its advantages of precision, flexibility, safety, visibility, etc., microfluidic technology has been widely used in the research of fluid flow in various scenarios and conditions. In particular, in recent years, microfluidic technology has also played a key role in simulating the energy and mass transport processes in porous media such as underground oil and gas production and liquid biological sample migration, showing great application potential.

[0005] The preparation of a microfluidic chip for simulating porous media is generally achieved by processing various microstructures, such as micro-columns, micro-ribs, micro-needles, etc. in its flow channels. Subsequently, relevant fluids can be injected into the processed microfluidic chip to study processes such as flow, phase change, and reaction in porous media.

[0006] However, the microstructures and the substrate of a general microfluidic chip for simulating porous media are integrated, and the microstructures are processed on the substrate. Therefore, there are generally some defects in the microfluidic chips for simulating porous media at present, specifically: the design of processing microstructures in the microfluidic chip is complex and the processing difficulty is large; in addition, the size of the microstructures is small, the strength is low, and they are easy to be damaged, so they are easy to break at some positions (such as the connection between the microstructures and the substrate) (especially under the long-term impact and pressure of the fluid). Once a certain microstructure is damaged, the entire microfluidic chip cannot meet the use requirements and must be replaced as a whole, indirectly increasing the cost.

[0007] In addition, in traditional microfluidic chips, the microstructures and the substrate are an integral structure. This traditional design results in that once a microfluidic chip is manufactured, its internal structure is completely determined and cannot be changed. Therefore, the versatility of a single microfluidic chip is poor and it can only be used in limited research scenarios. Summary of the Invention

[0008] To overcome the deficiencies of the above-mentioned prior art, the present invention provides a microfluidic chip for simulating porous media, which can simulate different porous media conditions, making the device versatile and capable of flexibly adapting to various research needs, and indirectly reducing the economic costs related to model manufacturing and use.

[0009] To achieve the above object, one or more embodiments of the present invention provide the following technical solutions:

[0010] In a first aspect, a microfluidic chip for simulating porous media is disclosed, comprising:

[0011] A magnetic substrate layer and a main flow channel layer arranged in sequence from bottom to top;

[0012] One end of the main flow channel layer is provided with an inlet flow channel, and the other end is provided with an outlet flow channel; the middle part of the main flow channel layer is a main flow channel cavity, and the inlet flow channel, the outlet flow channel and the main flow channel cavity are on the same plane of the main flow channel layer;

[0013] One side of the main flow channel layer is provided with a porous medium loading port;

[0014] Porous medium particles are introduced into the main flow channel cavity through the porous medium loading port, and are fixed by the magnetic attraction of the magnetic substrate layer, so as to form a porous medium region in the main flow channel cavity.

[0015] As a further technical solution, it further includes a cover layer, and the cover layer is arranged above the main flow channel layer;

[0016] Fluid injection holes and fluid outflow holes are arranged on the cover layer, and the fluid injection holes and the fluid outflow holes are respectively communicated with the inlet flow channel and the outlet flow channel after the assembly of each layer is completed.

[0017] As a further technical solution, positioning holes are opened at the edges of the magnetic substrate layer, the main flow channel layer and the cover layer, which is convenient for aligning each layer.

[0018] As a further technical solution, the porous medium loading port is provided with a matching loading port sealing plug for sealing the porous medium loading port.

[0019] As a further technical solution, the magnetic substrate layer has magnetism for adsorbing porous medium particles, and the main flow channel cavity is used for accommodating porous medium particles.

[0020] As a further technical solution, the porous medium particles are made of magnetic materials or contain partial magnetic materials, and their shapes include spherical, cylindrical, square, ellipsoidal or irregular shapes, etc.

[0021] As a further technical solution, the porous medium particles include multiple types, each type having a certain quantity, for free combination, and capable of forming different porous medium regions in the main channel cavity.

[0022] As a further technical solution, the inlet channel and the outlet channel are used for fluid inflow and outflow, and their forms are single-channel, multi-channel, shunt channel, etc.

[0023] In a second aspect, a manufacturing method of a microfluidic chip simulating a porous medium is disclosed, including the following steps:

[0024] Manufacture and process the main channel layer and the covering layer;

[0025] Align the positioning holes on the main channel layer and the covering layer, and assemble the two into one body;

[0026] Determine the characteristics of the porous medium region in the main channel cavity, including particle position, porosity, pore size distribution, particle size distribution, and permeability;

[0027] According to the characteristics of the determined porous medium region, select corresponding porous medium particles, introduce the porous medium particles into the main channel cavity through the porous medium loading port, and adjust the position of the porous medium particles;

[0028] Place the loading port sealing plug on the porous medium loading port and seal it;

[0029] Assemble the magnetic substrate layer with the main channel layer and the covering layer into one body, and the magnetic substrate layer fixes the porous medium particles in the main channel cavity.

[0030] As a further technical solution, the distribution diagram of the porous medium particles in the main channel cavity is projected onto the main channel layer by a projector to facilitate accurate adjustment of the position of the porous medium particles.

[0031] In a third aspect, a usage method of a microfluidic chip simulating a porous medium is disclosed, including the following steps:

[0032] Use connecting pipelines to connect the fluid container, the microfluidic pump, and the fluid injection hole;

[0033] Use connecting pipelines to connect the fluid outflow hole and the fluid collection tank;

[0034] Start the microfluidic pump to pump the fluid into the main channel cavity and make it flow through the porous medium region;

[0035] Characterize, monitor, and analyze the flow, diffusion, phase change, and reaction processes of the fluid;

[0036] The fluid flows out through the fluid outflow hole and is discharged into the fluid collection tank.

[0037] As a further technical solution, after use, turn off the microfluidic pump, remove the magnetic substrate layer, open the porous medium loading port, and use a micro magnet to guide and take out the porous medium particles;

[0038] Seal the porous medium loading port, pump in a cleaning agent to clean the flow channels and cavities of the microfluidic chip, and at the same time clean the taken-out porous medium particles for subsequent use.

[0039] The above one or more technical solutions have the following beneficial effects:

[0040] Based on the separately designed and processed layers of the microfluidic chip main body and the porous medium particles therein, the processing difficulty is reduced, parallel production is easy, and the processing cost of a single simulated porous medium microfluidic chip is reduced.

[0041] Since the porous medium particles are separated from the microfluidic chip main body, their introduction and removal methods are flexible, and local particle structure damage will not render the entire microfluidic chip scrapped, enhancing the overall reliability of the device.

[0042] In the same microfluidic chip main body, the distribution, composition ratio, etc. of the porous medium particles can be flexibly adjusted to simulate different porous medium conditions, such as porosity, permeability, particle non-uniformity, hydrophilicity and hydrophobicity of the particle surface, etc., endowing the device with versatility, being able to flexibly adapt to various research needs, and indirectly reducing the economic costs related to model manufacturing and use.

[0043] The advantages of the additional aspects of the present invention will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0045] Figure 1 It is a schematic diagram of the composition structure of the microfluidic chip for simulating a porous medium according to an embodiment of the present invention;

[0046] Figure 2 It is a plan view of the main flow channel layer according to an embodiment of the present invention;

[0047] Figure 3 It is a schematic assembly diagram of the microfluidic chip for simulating a porous medium according to an embodiment of the present invention;

[0048] In the figure, 01 is the magnetic substrate layer; 02 is the main channel layer; 03 is the cover layer; 04 are the porous medium particles; 05 are the positioning holes; 06 is the inlet channel; 07 is the outlet channel; 08 is the main channel cavity; 09 is the porous medium loading port; 10 is the loading port sealing plug; 11 are the fluid injection holes; 12 are the fluid outflow holes. Detailed implementation mode

[0049] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0050] It should be noted that the terms used herein are only for describing the specific implementation mode and are not intended to limit the exemplary implementation mode according to the present invention.

[0051] Without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0052] Embodiment 1

[0053] See the attached Figure 1 As shown, this embodiment discloses a microfluidic chip for simulating a porous medium, including:

[0054] The magnetic substrate layer 01, the main channel layer 02, the cover layer 03, and the porous medium particles 04 are combined to form a complete microfluidic chip. Among them, positioning holes 05 are designed at the edges of the magnetic substrate layer 01, the main channel layer 02, and the cover layer 03 to facilitate alignment of each layer; the magnetic substrate layer 01 has magnetism and can adsorb and fix magnetic materials; the front and rear ends of the main channel layer 02 are respectively designed with an inlet channel 06 and an outlet channel 07.

[0055] In this embodiment, the materials of the main channel layer 02 and the cover layer 03 can be selected from non-metallic materials such as glass materials and plastic materials.

[0056] See the attached Figure 2 As shown, a main channel cavity 08 is designed in the middle of the main channel layer 02; a porous medium loading port 09 is designed on one side of the main channel layer 02; a matching loading port sealing plug 10 is designed for the porous medium loading port 09 to seal the porous medium loading port 09; fluid injection holes 11 and fluid outflow holes 12 are designed on the cover layer 03, and the fluid injection holes 11 and the fluid outflow holes 12 can be respectively connected to the inlet channel 06 and the outlet channel 07 after the assembly of each layer is completed. The porous medium particles 04 are introduced into the main channel cavity 08 through the porous medium loading port 09 and are fixed by the magnetic attraction of the magnetic substrate layer 01, so as to form a porous medium region in the main channel cavity 08.

[0057] In the above microfluidic chip, the magnetic substrate layer 01 should have sufficient magnetism to fix the porous medium particles 04, and the shape of the magnetic substrate layer 01 is not restricted. The main channel cavity 08 is used to accommodate the porous medium particles 04, and the shape of the main channel cavity 08 is not restricted. The inlet channel 06 and the outlet channel 07 are used for the inflow and outflow of fluid, and their forms include but are not limited to single-channel, multi-channel, shunt channel, etc. The size of the porous medium loading port 09 should be sufficient to accommodate the porous medium particles 04 to enter the main channel cavity 08. The shapes of the porous medium loading port 09 and the supporting loading port sealing plug 10 are not restricted. The porous medium particles 04 should be made of magnetic materials or contain partial magnetic materials, and their shapes include but are not limited to spherical, cylindrical, square, ellipsoidal, irregular, etc. There should be multiple types of porous medium particles 04, and each type has a certain quantity, so as to achieve free combination and form different porous medium regions in the main channel cavity 08.

[0058] When forming different porous medium regions, the porous medium particles 04 are filled into the main channel cavity 08, and porous medium regions are formed in the main channel cavity 08. The quantity, type, and distribution of the porous medium particles 04 are different, and the properties of the corresponding porous medium regions are also different.

[0059] The magnetism in the microfluidic chip is provided by the magnetic substrate layer 01. The required magnetic magnitude is different under different conditions. For example, under high pressure and high flow rate, stronger magnetism is required to fix the porous medium particles 04. Therefore, the magnitude of the magnetism changes with the working conditions of the microfluidic chip, and an exact value cannot be given. In actual use, the magnetism can be made as large as possible, and the magnetism has no influence on the flow of general fluids.

[0060] Example Two

[0061] See Appendix Figure 3 As shown, the purpose of this embodiment is to provide a manufacturing method for a microfluidic chip simulating porous media, mainly including the following steps:

[0062] Step One: Use CAD software to draw and design each layer of the above microfluidic chip;

[0063] Step Two: Use methods such as photolithography, etching, or 3D printing to manufacture and process the main channel layer 02 and the covering layer 03;

[0064] Step Three: Align the positioning holes 05 on the main channel layer 02 and the covering layer 03, and assemble and bond the two into one body;

[0065] Step Four: Determine the characteristics of the porous medium regions in the main channel cavity 08, including particle position, porosity, pore size distribution, particle size distribution, permeability, etc.;

[0066] Step Five: According to the characteristics of the porous medium region determined in Step Four, select the corresponding porous medium particles 04, introduce the porous medium particles 04 into the main channel cavity 08 through the porous medium loading port 09, and adjust the position of the porous medium particles 04;

[0067] Step Six: Place the loading port sealing plug 10 on the porous medium loading port 09 and seal it;

[0068] Step Seven: Assemble and bond the magnetic substrate layer 01, the main channel layer 02, and the covering layer 03 into one body, and the magnetic substrate layer 01 fixes the porous medium particles 04 in the main channel cavity 08.

[0069] In the above Step Four and Step Five, the number, position, size, shape, surface properties, etc. of the porous medium particles 04 in the main channel cavity 08 can be determined manually or randomly generated by a computer according to the characteristics of the porous medium region. The distribution map of the porous medium particles 04 in the main channel cavity 08 can be projected onto the main channel layer 02 by a high-resolution projector to facilitate the precise adjustment of the position of the porous medium particles in Step Five. In the above Step Five, the porous medium particles 04 are guided to the set position by a small magnet, and the position adjustment process of the porous medium particles 04 is observed and calibrated through a microscope. In the above Step Three, the main channel layer 02 and the covering layer 03 should be firmly bonded together to ensure tightness. In the above Step Seven, the combination of the magnetic substrate layer 01 and the other two layers only needs to ensure that the magnetic substrate layer 01 can fix the porous medium particles 04, without the need for rigid bonding, so as to facilitate installation / dismantling, fixing the porous medium particles 04 / moving the porous medium particles 04.

[0070] The above distribution map is manually drawn using CAD software or generated based on computer algorithms. The distribution map contains the position, size, and shape information of the porous medium particles. The distribution map is projected onto the main channel layer 02 by a projector, and then the porous medium particles are placed into the main channel cavity 08, and the position of the porous medium particles is adjusted to align with the projected pattern.

[0071] It should be noted that the above small magnet is not a part of the microfluidic chip and is only used when manufacturing the microfluidic chip.

[0072] After manufacturing the microfluidic chip with a porous medium region based on the above method, connect the fluid container, the microfluidic pump, and the fluid injection hole 11 using connecting pipes. Connect the fluid outflow hole 12 and the fluid collection tank using connecting pipes. Turn on the microfluidic pump to pump the fluid into the main channel cavity 08, and let it flow through the porous medium region. Characterize, monitor, and analyze the processes of fluid flow, diffusion, phase change, reaction, etc. through various sensors, optoelectronic signals, or image signals. This process is a conventional operation in the art and will not be described in detail here. Additionally, this process is a specific simulation process, and simulation operations are carried out as needed. The fluid flows out through the fluid outflow hole 12 and is discharged into the fluid collection tank. After the research is completed, turn off the microfluidic pump, remove the magnetic substrate layer 01, open the porous medium loading port 09, and use a micro magnet to guide and take out the porous medium particles 04. Seal the porous medium loading port 09 again, pump in a cleaning agent to clean the channels and cavities of the microfluidic chip, and at the same time clean the taken-out porous medium particles 04 for subsequent use.

[0073] Although the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, it is not a limitation on the protection scope of the present invention. Those skilled in the art should understand that based on the technical solutions of the present invention, various modifications or deformations that can be made without creative efforts by those skilled in the art are still within the protection scope of the present invention.

Claims

1. A microfluidic chip for simulating a porous medium, characterized in that, Comprising: A magnetic lining layer and a main flow channel layer arranged successively from bottom to top; One end of the main flow channel layer is provided with an inlet flow channel, and the other end is provided with an outlet flow channel; the middle part of the main flow channel layer is a main flow channel cavity, and the inlet flow channel, the outlet flow channel and the main flow channel cavity are located on the same plane of the main flow channel layer; A porous medium loading port is arranged on one side of the main flow channel layer; Porous medium particles are introduced into the main flow channel cavity through the porous medium loading port and fixed by the magnetic attraction of the magnetic lining layer, so as to form a porous medium region in the main flow channel cavity.

2. The microfluidic chip for simulating a porous medium according to claim 1, characterized in that, It further includes a covering layer, and the covering layer is arranged above the main flow channel layer; Fluid injection holes and fluid outflow holes are arranged on the covering layer, and the fluid injection holes and the fluid outflow holes are respectively communicated with the inlet flow channel and the outlet flow channel after the assembly of each layer is completed.

3. The microfluidic chip for simulating porous media according to claim 2, characterized in that, Positioning holes are provided at the edges of the magnetic lining layer, the main flow channel layer and the covering layer, which are convenient for aligning each layer.

4. The microfluidic chip for simulating a porous medium according to claim 1, characterized in that, A loading port sealing plug is provided for the porous medium loading port to seal the porous medium loading port.

5. The microfluidic chip for simulating porous media according to claim 1, characterized in that, The porous medium particles are made of magnetic materials or contain partial magnetic materials, and their shapes include spherical, cylindrical, square, ellipsoidal or irregular shapes.

6. The microfluidic chip for simulating a porous medium according to claim 1, characterized in that, The inlet flow channel and the outlet flow channel are used for fluid inflow and outflow, and their forms are single-channel, multi-channel or shunt channels.

7. A method for fabricating a microfluidic chip for simulating a porous medium, characterized in that, Including the following steps: Manufacture and process the main flow channel layer and the covering layer; Align the positioning holes on the main flow channel layer and the covering layer, and assemble the two into one body; Determine the characteristics of the porous medium region in the main flow channel cavity, including particle position, porosity, pore size distribution, particle size distribution and permeability; According to the characteristics of the determined porous medium region, select corresponding porous medium particles, introduce the porous medium particles into the main flow channel cavity through the porous medium loading port, and adjust the position of the porous medium particles; Place the loading port sealing plug on the porous medium loading port and seal it; Assemble the magnetic lining layer with the main flow channel layer and the covering layer into one body, and the magnetic lining layer fixes the porous medium particles in the main flow channel cavity.

8. A method for using a microfluidic chip for simulating a porous medium according to claim 2, characterized in that, Including the following steps: Use connecting pipelines to connect a fluid container, a microfluidic pump and the fluid injection holes; Use connecting pipelines to connect the fluid outflow holes and a fluid collection tank; Start the microfluidic pump to pump the fluid into the main flow channel cavity and make it flow through the porous medium region; Characterize, monitor and analyze the flow, diffusion, phase change and reaction processes of the fluid; The fluid flows out through the fluid outflow holes and is discharged into the fluid collection tank; After use, turn off the microfluidic pump, disassemble the magnetic lining layer, open the porous medium loading port, and use a micro magnet to guide and take out the porous medium particles; Seal the porous medium loading port, pump in a cleaning agent to clean the flow channels and cavities of the microfluidic chip, and at the same time clean the taken-out porous medium particles for subsequent use.

Images