Design method and system of micro-fluidic detection device based on COMSOL

Abstract

The invention discloses a design method and system of a COMSOL-based microfluidic detection device, and the method comprises the following steps: determining the structural size of a microfluidic device by taking the flow velocity of liquid in the microfluidic device as a control target; physical parameters of the capillary pump are determined through experimental determination; describing momentum transfer by using a Navier-Stokes equation, and establishing a control equation of fluid motion in combination with a mass conservation continuity equation; based on the structure size of the microfluidic device, the physical parameters of the capillary pump and the control method, constructing a microfluidic model guided by the micropump by using COMSOL, and performing simulation; parameters of the microfluidic model are adjusted according to simulation result feedback, and the design of the microfluidic device is completed. A two-dimensional model is used for approximately simulating a three-dimensional microfluidic structure, an actual experiment and a simulation experiment are combined, a high-value theoretical reference basis is provided for experimental research, and the device is convenient to adjust and optimize in the actual experiment.

Description

Technical Field

[0001] The present invention belongs to the technical field of microfluidics, and particularly relates to a design method and system for a microfluidic detection device based on COMSOL. Background Art

[0002] As an emerging technology, microfluidics has penetrated into fields such as biomedical diagnosis, drug screening, environmental monitoring, and synthetic biology. For example, during the COVID-19 pandemic, microfluidic-based nucleic acid rapid testing devices achieved integrated detection of "sample in - result out". In the future, with the integration of nanotechnology and 3D printing, microfluidics will accelerate the development of precision medicine, personalized treatment, and green chemistry. However, its large-scale production and standardized design are still challenges that need to be urgently overcome. Through a precisely designed microchannel network, this technology enables operations such as mixing, separation, and reaction of fluids under microscale effects such as laminar flow, surface tension, and electroosmotic flow. The required sample volume is only one-thousandth of that of traditional methods, while significantly improving the analysis speed and sensitivity. However, how to control the fluid behavior by relying on the capillary seepage effect of the micropump configured by the structure itself without an external pump is still a research problem that needs to be urgently solved.

[0003] In recent years, COMSOL Multiphysics has demonstrated significant advantages in the field of microfluidics technology simulation with its multi-physics field coupling modeling ability. Microfluidic systems usually involve multi-field coupling problems such as fluid mechanics, mass transfer diffusion, and chemical reactions. COMSOL can achieve seamless integration and dynamic interaction analysis of these physical fields through modular interfaces. In addition, the cross-scale simulation ability of COMSOL can take into account the global characteristics of micron-scale channels and local microscopic effects (such as surface wettability, particle-wall interaction), providing a theoretical basis for the development of high-precision devices such as molecular-level detection devices and micromixers. Its flexible custom equation interface can also be extended to the modeling of special scenarios such as non-Newtonian fluids and biomolecular transport. However, current microfluidics research still faces challenges: complex multiphase flow models need to rely on high-precision experimental data for verification, lacking a systematic theoretical guidance and optimization design framework. Therefore, how to build a high-fidelity model through COMSOL and establish a "design - simulation - manufacturing" closed-loop system is a key topic for the intelligent design of microfluidics technology. Summary of the Invention

[0004] The present invention aims to solve the deficiencies of the prior art and provides the following solutions:

[0005] A design method for a microfluidic detection device based on COMSOL, comprising the following steps:

[0006] Taking the liquid flow velocity in the microfluidic device as the control target, determine the structural dimensions of the microfluidic device;

[0007] Determine the physical parameters of the capillary pump through experimental measurement;

[0008] Use the Navier-Stokes equation to describe momentum transfer, and combine it with the mass conservation continuity equation to establish the control equation of fluid motion;

[0009] Based on the structural dimensions of the microfluidic device, the physical parameters of the capillary pump, and the control method, use COMSOL to construct a microfluidic model guided by the micropump and conduct simulations;

[0010] According to the feedback of the simulation results, adjust the parameters of the microfluidic model to complete the design of the microfluidic device.

[0011] Preferably, the method for constructing the control equation includes:

[0012] Construct the mass conservation continuity equation:

[0013]

[0014] where ρ represents the fluid density, u represents the flow velocity after the test liquid enters the microfluidic device, x represents the x-axis direction, y represents the y-axis direction, z represents the z-axis direction, and t represents time;

[0015] Based on the mass conservation continuity equation and the Navier-Stokes equation, construct the control equation:

[0016]

[0017] where, represents the gradient operator, represents the Laplace operator, μ represents the dynamic viscosity of the fluid, and p represents the channel pressure of the fluid on the microfluidic chip.

[0018] Preferably, the method for constructing a microfluidic model guided by the micropump and conducting simulations includes:

[0019] Based on the structural dimensions of the microfluidic device and the physical parameters of the capillary pump, determine the size of the micropump and the spacing between micropumps, use CAD to construct a microfluidic device model and import it into COMSOL;

[0020] Select a two-dimensional graph, add multiple physical fields, use the two-phase flow in the MEMS module to simulate the liquid and air in the flow system, set the parameter attributes, and use the initial conditions and boundary conditions to constrain the equation, and conduct multi-physical field coupling;

[0021] Perform mesh division on the microfluidic device model, and super-refine the mesh according to the principle of hydrodynamics;

[0022] Add transient analysis, adjust the absolute tolerance, time stepping, termination method, and criterion configuration in the solver according to requirements, and obtain the volume fraction of the capillary filling process at different times through calculation and post-processing;

[0023] Consider the influence of different combinations of contact angles, micropumps, and fluid viscosity channel array parameters on fluid velocity, adjust the parameter combinations according to requirements and simulation results, and analyze the volume change of two-phase flow under different combination conditions.

[0024] The present invention also provides a design system for a microfluidic detection device based on COMSOL. The design system applies the design method described in any one of the above, and includes: a size determination module, a parameter determination module, an equation construction module, a model construction module, and a parameter adjustment module;

[0025] The size determination module determines the structural size of the microfluidic device with the liquid flow velocity in the microfluidic device as the control target;

[0026] The parameter determination module determines the physical parameters of the capillary pump through experimental measurement;

[0027] The equation construction module uses the Navier-Stokes equation to describe momentum transfer and combines the mass conservation continuity equation to establish the control equation of fluid motion;

[0028] The model construction module constructs a microfluidic model guided by a micropump using COMSOL and conducts simulations based on the structural size of the microfluidic device, the physical parameters of the capillary pump, and the control method;

[0029] The parameter adjustment module is used to adjust the parameters of the microfluidic model according to the feedback of the simulation results to complete the design of the microfluidic device.

[0030] Preferably, the working process of the equation construction module includes:

[0031] Construct the mass conservation continuity equation:

[0032]

[0033] where ρ represents the fluid density, u represents the flow velocity of the test liquid after entering the microfluidic device, x represents the x-axis direction, y represents the y-axis direction, z represents the z-axis direction, and t represents time;

[0034] Construct the control equation based on the mass conservation continuity equation and the Navier-Stokes equation:

[0035]

[0036] where represents the gradient operator, The Laplace operator is denoted as, the dynamic viscosity of the fluid is denoted as μ, and the channel pressure of the fluid on the microfluidic chip is denoted as p.

[0037] Preferably, the working process of the model construction module includes:

[0038] Determine the size of the micropump and the spacing between micropumps based on the structural dimensions of the microfluidic device and the physical parameters of the capillary pump, use CAD to construct a microfluidic device model and import it into COMSOL;

[0039] Select a two-dimensional graph, add multiple physical fields, use the two-phase flow in the MEMS module to simulate the liquid and air in the flow system, set the parameter attributes, and use the initial conditions and boundary conditions to constrain the equations, and perform multi-physical field coupling;

[0040] Perform mesh generation on the microfluidic device model, and super-refine the mesh according to the principle of hydrodynamics;

[0041] Add transient analysis, adjust the configuration of the absolute tolerance, time step, termination method and criterion in the solver according to requirements, and obtain the volume fraction of the capillary filling process at different times through calculation and post-processing;

[0042] Consider the influence of the parameter combinations of different contact angles, micropumps, and fluid viscosity channel arrays on the fluid velocity, adjust the parameter combinations according to requirements and simulation results, and analyze the volume change of the two-phase flow under different combination conditions.

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0044] Based on the microfluidic device manufacturing technology and the capillary microfluidic effect, the present invention determines the geometric dimension parameters of the micropump and microvalve of the basic microfluidic device, constructs an adjustable digital microfluidic model, and can adjust the shape and size of the pump according to requirements to optimize the performance of the microfluidic device.

[0045] In the simulation of the microfluidic model of the present invention, physical properties such as liquid viscosity and density are considered, micropumps with different geometric structures and different geometric sizes are considered, and the influence of the performance of different substrate materials (such as hydrophilicity, surface charge, chemical stability, and mechanical strength) on the performance of the microfluidic model is considered. A single parameter can be changed to independently study the overall influence of this parameter on the fluid model.

[0046] The present invention approximately simulates the three-dimensional structure microfluidic structure using a two-dimensional model, combines actual experiments with simulation experiments, provides a high-value theoretical reference for experimental research, and is convenient for adjusting and optimizing the device in actual experiments. Description of the Drawings

[0047] To more clearly illustrate the technical solution of the present invention, the accompanying drawings required for use in the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0048] Figure 1 Schematic diagram of the method flow of the embodiment of the present invention;

[0049] Figure 2 Schematic diagram of the microfluidic device model of the embodiment of the present invention;

[0050] Figure 3 Schematic diagram of the mesh division of the model of the embodiment of the present invention;

[0051] Figure 4 Schematic diagram of the volume fraction of the microfluidic device at 0 s in the embodiment of the present invention;

[0052] Figure 5 Schematic diagram of the change in volume fraction of the microfluidic device at 0.1 s in the embodiment of the present invention;

[0053] Figure 6 Schematic diagram of the change in volume fraction of the microfluidic device at 1.85 s in the embodiment of the present invention;

[0054] Figure 7 Schematic diagram of the liquid flow rate of the embodiment of the present invention;

[0055] Figure 8 Schematic diagram of the liquid pressure of the embodiment of the present invention. Specific embodiments

[0056] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only 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 creative efforts belong to the scope of protection of the present invention.

[0057] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0058] Embodiment 1

[0059] In this embodiment, as Figure 1 shown, a design method for a microfluidic detection device based on COMSOL includes the following steps:

[0060] S1. Determine the structural dimensions of the microfluidic device with the liquid flow velocity in the microfluidic device as the control target.

[0061] S2. Determine the physical parameters of the capillary pump through experimental measurement.

[0062] In this embodiment, based on the microfluidic device manufacturing technology and the capillary microfluidic effect, determine the liquid flow velocity in the microfluidic device as the control target, determine the structural dimensions of the microfluidic device, and determine the relevant physical parameters of the capillary pump through experimental measurement or empirical value selection. The operating parameters of the microfluidic model include capillary pump size, contact angle, liquid tension, interface thickness, relative dielectric constant of the solution, solution diffusion coefficient, and solution viscosity, etc.

[0063] S3. Use the Navier-Stokes equation to describe momentum transfer, and combine with the mass conservation continuity equation to establish the control equation of fluid motion.

[0064] In this embodiment, use the Navier-Stokes equation to describe momentum transfer, including surface tension and mass conservation, and through a redesigned level set method to represent the separation state between air and fluid, combine with the mass conservation continuity equation to establish the control equation of fluid motion, and realize the simulation of fluid flow in the device. For the case where the liquid is in a static equilibrium state, the surface Laplace equation and Young's equation of the capillary are defined.

[0065] Construct the mass conservation continuity equation:

[0066]

[0067] where ρ represents the fluid density, u represents the flow velocity of the test liquid after entering the microfluidic device, x represents the x-axis direction, y represents the y-axis direction, z represents the z-axis direction, t represents time, represents the net outflow mass of the fluid, represents the mass reduction over time;

[0068] In addition to following the law of mass conservation, the fluid in the microfluidic chip should also abide by the law of momentum conservation, that is, the sum of the rate of change of the fluid's momentum with respect to time and the external force acting on it is equal, namely:

[0069]

[0070] where Φ represents the porosity of the microfluidic chip surface, k represents the permeability of the chip surface, represents the gradient operator, p represents the channel pressure of the fluid on the microfluidic chip;

[0071] Consider that at the inlet of the microfluidic device, since it is a fluid inlet, the inlet capillary pressure and the initial phase pressure it receives are:

[0072]

[0073] Among them, γ represents the surface tension, θ represents the wetting angle, d represents the thickness of the device chip, and s0 represents the initial residual wetting phase saturation;

[0074] Based on the mass conservation continuity equation and the Navier-Stokes equation, the control equations are constructed:

[0075]

[0076]

[0077] Among them, represents the gradient operator, represents the Laplace operator, and μ represents the dynamic viscosity of the fluid.

[0078] S4. Based on the structural dimensions of the microfluidic device, the physical parameters of the capillary pump, and the control method, use COMSOL to construct a microfluidic model guided by the micropump and perform simulations.

[0079] The method for constructing a microfluidic model guided by the micropump and performing simulations includes: determining the size of the micropump and the spacing of the micropump based on the structural dimensions of the microfluidic device and the physical parameters of the capillary pump, using CAD to construct a microfluidic device model and import it into COMSOL; selecting a two-dimensional graph, adding multiple physical fields, using the two-phase flow in the MEMS module to simulate the liquid and air in the flow system, setting parameter attributes and using the initial conditions and boundary conditions to constrain the equations, and performing multi-physical field coupling; performing mesh division on the microfluidic device model, and super-refining the mesh according to the principle of hydrodynamics; adding transient analysis, adjusting the absolute tolerance, time step, termination method, and criterion configuration in the solver according to requirements, and obtaining the volume fraction of the capillary filling process at different times through calculation and post-processing; considering the influence of different combinations of contact angles, micropumps, and fluid viscosity channel arrays on the fluid velocity, adjusting the parameter combinations according to requirements and simulation results, and analyzing the volume change of the two-phase flow under different combination conditions.

[0080] When the liquid is in a static equilibrium state, the surface of the capillary is defined by two conditions, namely the Laplace equation and the Young's equation. The former stipulates the pressure drop at the liquid-gas interface as the liquid-gas surface tension γ lg The relationship with the interface curvatures k1 and k2: —

[0081] Δp = p l -p g = γ 1g (k1 + k2)

[0082] Among them, p lDenotes liquid pressure, p g Denotes gas pressure; Young's equation involves solid-liquid γ ls Liquid-gas γ lg And gas-solid γ gs Surface tension and the contact angle θ at the solid-liquid-gas interface:

[0083] γ 1g cosθ + γ ls = γ gs

[0084] The liquid to be measured reaches the edge of the microchannel outlet, and the contact angle reaches the critical advancing angle value θ α At this time, the cut-off valve cannot block. The analytical expression of the critical pressure can be obtained:

[0085]

[0086] Among them, β is the channel expansion angle, r is its radius; the maximum pressure jump obtained when θ α + β is equal to or greater than 180°.

[0087] S5. Adjust the parameters of the microfluidic model according to the simulation results feedback to complete the design of the microfluidic device.

[0088] Example Two

[0089] In this example, a design system for a microfluidic detection device based on COMSOL includes: a size determination module, a parameter determination module, an equation construction module, a model construction module, and a parameter adjustment module.

[0090] The size determination module takes the liquid flow velocity in the microfluidic device as the control target to determine the structural size of the microfluidic device.

[0091] The parameter determination module determines the physical parameters of the capillary pump through experimental measurement.

[0092] The equation construction module uses the Navier-Stokes equation to describe momentum transfer and combines the mass conservation continuity equation to establish the control equation of fluid motion.

[0093] The working process of the equation construction module includes: constructing the mass conservation continuity equation:

[0094]

[0095] Among them, ρ represents the fluid density, u represents the flow velocity of the liquid to be measured after entering the microfluidic device, x represents the x-axis direction, y represents the y-axis direction, z represents the z-axis direction, and t represents time; based on the mass conservation continuity equation and the Navier-Stokes equation, the control equation is constructed:

[0096]

[0097] Among them, represents the gradient operator, represents the Laplace operator, μ represents the dynamic viscosity of the fluid, and p represents the channel pressure of the fluid on the microfluidic chip.

[0098] Based on the structural dimensions of the microfluidic device, the physical parameters and control methods of the capillary pump, the model construction module uses COMSOL to construct a microfluidic model guided by the micropump and perform simulations.

[0099] The working process of the model construction module includes: determining the size of the micropump and the spacing between micropumps based on the structural dimensions of the microfluidic device and the physical parameters of the capillary pump, using CAD to construct a microfluidic device model and importing it into COMSOL; selecting two-dimensional graphics, adding multiple physical fields, using the two-phase flow in the MEMS module to simulate the liquid and air in the flow system, setting parameter attributes and using initial conditions and boundary conditions to constrain the equations, and performing multi-physical field coupling; meshing the microfluidic device model and ultra-refining the mesh according to the principle of hydrodynamics; adding transient analysis, adjusting the absolute tolerance, time stepping, termination method and criterion configuration in the solver according to requirements, and obtaining the volume fraction of the capillary filling process at different times through calculation and post-processing. Considering the influence of different combinations of contact angles, micropumps, and fluid viscosity channel arrays on the fluid velocity, adjusting the parameter combinations according to requirements and simulation results, and analyzing the volume change of the two-phase flow under different combination conditions.

[0100] The parameter adjustment module is used to adjust the parameters of the microfluidic model according to the feedback of the simulation results to complete the design of the microfluidic device.

[0101] Embodiment III

[0102] In this embodiment, the specific implementation method will be introduced:

[0103] In COMSOL, select the "two-dimensional" spatial dimension in the "Model Wizard" to simulate the simulation model of the new microfluidic detection device by implementing a two-dimensional model. In the selection of physical fields, "laminar flow spf" is used to simulate the fluid flow model and "phase field pf" is used to simulate the interaction model of two fluids, liquid and air.

[0104] Create a geometric model. Design a microfluidic device according to the principle of hydrodynamics and design experience and use AutoCAD software to draw the two-dimensional structure of the device. The model is as Figure 2As shown, it is rectangular as a whole. The liquid inlet channel is distributed on the left side. The capillary pump area is distributed on the right side of the inlet channel and functions to pump the fluid. Further to the right is the detection area where the detection nano-pore array sensors are distributed, and the rightmost is the fluid control area where the capillary cut-off valve is distributed. In the microfluidic simulation model, the liquid and air are respectively described as two different fluids. The model is mainly divided into the capillary pump area initially occupied by air and the inlet occupied by the liquid. The main control parameters are the geometry and size of the capillary pump and the width of the channel.

[0105] Call the air material in the database and set the air fluid in the capillary pump area to simulate the initialization state where air occupies the entire microfluidic device in the actual experimental environment. Call or create the liquid material according to the design requirements and set the liquid at the channel inlet;

[0106] In the "laminar spf" physical field, set the fluid environment, and use the initial conditions and boundary conditions to constrain the equations, including fluid properties, walls, and initial values. Set the inlet, select the inlet boundary on the leftmost side of the model, set the outlet, select the boundary at the lower right of the model, and set the initial pressure.

[0107] As Figure 3 described, perform mesh generation on the constructed microfluidic device model. The built-in mesh generation function of COMSOL can be used. Select "user-controlled mesh", calibrate with "hydrodynamics", set the mesh refinement predefined according to the design accuracy requirements, and set "free triangular network" for mesh refinement, and then generate the mesh.

[0108] In the "phase field pf", set the two flow phases of air and liquid through "initial values", set "wetting wall" and adjust the contact angle therein to adjust the interaction between the liquid and the microfluidic device. Input the coupled fluid of the entire model, as well as experimental condition parameters such as its dynamic viscosity, density, and temperature in the "multiphysics".

[0109] Add a transient study, adjust the absolute tolerance, time step, termination method, and criterion configuration in the solver according to the requirements, set an appropriate output time step, and use the physical field control tolerance.

[0110] As Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 、 Figure 8 shown, post-process the calculation results to obtain the liquid volume fraction change diagram, pressure diagram, and flow velocity diagram.

[0111] The embodiments described above are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A design method of a microfluidic detection device based on COMSOL, characterized in that, It includes the following steps: Taking the liquid flow velocity in the microfluidic device as the control target, determine the structural dimensions of the microfluidic device; Determine the physical parameters of the capillary pump through experimental measurement; Use the Navier-Stokes equation to describe momentum transfer, and combine with the mass conservation continuity equation to establish the control equation of fluid motion; Based on the structural dimensions of the microfluidic device, the physical parameters of the capillary pump, and the control method, use COMSOL to construct a microfluidic model guided by a micropump and perform simulation; According to the simulation results, feedback and adjust the parameters of the microfluidic model to complete the design of the microfluidic device.

2. The design method of a microfluidic detection device based on COMSOL according to claim 1, wherein, The method for constructing the control equation includes: Construct the mass conservation continuity equation: where ρ represents the fluid density, u represents the flow velocity after the test liquid enters the microfluidic device, x represents the x-axis direction, y represents the y-axis direction, z represents the z-axis direction, and t represents time; Based on the mass conservation continuity equation and the Navier-Stokes equation, construct the control equation: Among them, represents the gradient operator, represents the Laplace operator, μ represents the dynamic viscosity of the fluid, and p represents the channel pressure of the fluid on the microfluidic chip.

3. The design method of a microfluidic detection device based on COMSOL according to claim 1, wherein The method for constructing a microfluidic model guided by a micropump and performing simulation includes: Based on the structural dimensions of the microfluidic device and the physical parameters of the capillary pump, determine the size of the micropump and the spacing of the micropumps, use CAD to construct a microfluidic device model and import it into COMSOL; Select a two-dimensional graph, add multiple physical fields, use the two-phase flow in the MEMS module to simulate the liquid and air in the flow system, set the parameter attributes, and use the initial conditions and boundary conditions to constrain the equation, and perform multi-physical field coupling; Perform mesh division on the microfluidic device model, and super-refine the mesh according to the principle of hydrodynamics; Add transient analysis, adjust the absolute tolerance, time step, termination method, and criterion configuration in the solver according to requirements, and obtain the volume fraction of the capillary filling process at different times through calculation and post-processing; Consider the influence of different combinations of contact angles, micropumps, and fluid viscosity channel arrays on the fluid velocity, adjust the parameter combinations according to requirements and simulation results, and analyze the volume change of the two-phase flow under different combination conditions.

4. A design system for a microfluidic detection device based on COMSOL, the design system applying the design method according to any one of claims 1-3, characterized in that, It includes: A size determination module, a parameter determination module, an equation construction module, a model construction module, and a parameter adjustment module; The size determination module takes the liquid flow velocity in the microfluidic device as the control target and determines the structural dimensions of the microfluidic device; The parameter determination module determines the physical parameters of the capillary pump through experimental measurement; The equation construction module uses the Navier-Stokes equation to describe momentum transfer and combines with the mass conservation continuity equation to establish the control equation of fluid motion; The model construction module constructs a microfluidic model guided by a micropump and performs simulation using COMSOL based on the structural dimensions of the microfluidic device, the physical parameters of the capillary pump, and the control method; The parameter adjustment module is used to feedback and adjust the parameters of the microfluidic model according to the simulation results to complete the design of the microfluidic device.

5. The design system of a microfluidic detection device based on COMSOL according to claim 4, characterized in that, The working process of the equation construction module includes: Construct the mass conservation continuity equation: Where ρ represents the fluid density, u represents the flow velocity after the liquid to be measured enters the microfluidic device, x represents the x-axis direction, y represents the y-axis direction, z represents the z-axis direction, and t represents time; The control equation is constructed based on the mass conservation continuity equation and the Navier-Stokes equation: Among them, represents the gradient operator, represents the Laplace operator, μ represents the dynamic viscosity of the fluid, and p represents the channel pressure of the fluid on the microfluidic chip.

6. The design system of a microfluidic detection device based on COMSOL according to claim 4, wherein The working process of the model construction module includes: Determine the size of the micropump and the spacing between micropumps based on the structural dimensions of the microfluidic device and the physical parameters of the capillary pump, use CAD to construct a microfluidic device model and import it into COMSOL; Select a two-dimensional graph, add multiple physical fields, use the two-phase flow in the MEMS module to simulate the liquid and air in the flow system, set the parameter attributes, and use the initial conditions and boundary conditions to constrain the equation, and perform multi-physical field coupling; Perform mesh division on the microfluidic device model and super-refine the mesh according to the principle of hydrodynamics; Add transient analysis, adjust the absolute tolerance, time step, termination method and criterion configuration in the solver according to requirements, and obtain the volume fraction of the capillary filling process at different times through calculation and post-processing; Consider the influence of different combinations of contact angles, micropumps, and fluid viscosity channel arrays on the fluid velocity, adjust the parameter combinations according to requirements and simulation results, and analyze the volume change of the two-phase flow under different combination conditions.

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