A COMSOL-based microfluidic detection device design method and system

Abstract

The application discloses a COMSOL-based microfluidic detection device design method and system, which comprises the following steps: taking the liquid flow speed in the microfluidic device as a control target, determining the structural size of the microfluidic device; determining the physical parameters of the capillary pump through experimental measurement; using the Navier-Stokes equation to describe momentum transfer, and combining the mass conservation continuity equation to establish the control equation of fluid motion; based on the structural size of the microfluidic device, the physical parameters of the capillary pump and the control method, using COMSOL to construct a micro-pump-guided microfluidic model and to simulate; according to the simulation result, adjusting the parameters of the microfluidic model to complete the design of the microfluidic device. The application uses a two-dimensional model to simulate a three-dimensional microfluidic structure, combines the actual experiment with the simulation experiment, provides a high-value theoretical reference for the experimental research, and is convenient for adjusting and optimizing the device in the actual experiment.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of microfluidics, and particularly relates to a design method and system of a microfluidic detection device based on COMSOL. BACKGROUND

[0002] As a new technology, microfluidics has penetrated into the fields of biomedical diagnosis, drug screening, environmental monitoring and synthetic biology. For example, in the new crown epidemic, the nucleic acid rapid detection equipment based on microfluidics realizes the 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, but its large-scale production and standardized design still need to be broken through. The technology realizes mixing, separation and reaction through microscale effects such as laminar flow, surface tension and electroosmotic flow in a precisely designed microchannel network, and the required sample volume is only one thousandth of that of traditional methods, while the analysis speed and sensitivity are significantly improved. However, how to control the fluid behavior by relying on the capillary force seepage effect of the structure itself without external pumps is still a research problem that needs to be solved.

[0003] In recent years, COMSOL Multiphysics has shown significant advantages in the simulation field of microfluidic technology due to its multi-physical field coupling modeling capability. Microfluidic systems usually involve multi-field coupling problems such as fluid mechanics, mass transfer diffusion and chemical reaction, and COMSOL can realize seamless integration and dynamic interactive analysis of these physical fields through modular interfaces. In addition, the cross-scale simulation capability of COMSOL can take into account the global characteristics and local micro effects (such as surface wettability and particle-wall interaction) of micron-scale flow channels, providing a theoretical basis for the development of molecular-level detection devices and micro-mixers. Its flexible custom equation interface can also be extended to modeling of non-Newtonian fluids, biomolecular transport and other special scenarios. However, current microfluidic research still faces challenges: complex multiphase flow models need to rely on high-precision experimental data for verification, and there is a lack of 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 issue for the intelligent design of microfluidic technology. SUMMARY

[0004] The application aims to solve the problems of the prior art and provides the following solutions:

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

[0006] Determine the structure size of the microfluidic device with the liquid flow speed in the microfluidic device as the control target;

[0007] The physical parameters of the capillary pump are determined through experiments;

[0008] The control equation of fluid motion is established by using the Navier-Stokes equation to describe momentum transfer and combining the mass conservation continuity equation;

[0009] Based on the structural size of the microfluidic device, the physical parameters of the capillary pump and the control method, a micro-pump guided microfluidic model is constructed by using COMSOL and simulation is performed;

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

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

[0012] The mass conservation continuity equation is constructed:

[0013]

[0014] Wherein, p represents the fluid density, u represents the flow rate of the liquid to be tested 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;

[0015] The control equation is constructed based on the mass conservation continuity equation and the Navier-Stokes equation:

[0016]

[0017] Wherein, The gradient operator is represented by The Laplacian operator is represented by μ, which 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 the micro-pump guided microfluidic model and performing simulation comprises:

[0019] Based on the structural size of the microfluidic device and the physical parameters of the capillary pump, the size of the micro-pump and the distance between the micro-pumps are determined, and a microfluidic device model is constructed using CAD and imported 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 perform multiple physical field coupling;

[0021] The microfluidic device model is meshed, and the mesh is super-fined according to the principle of fluid dynamics;

[0022] Add transient analysis, adjust the absolute tolerance, time step, termination method and criterion configuration in the solver according to the 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 angle, micropump, fluid viscosity channel array parameters on fluid velocity, adjust the parameter combination according to the requirements and simulation results, and analyze the volume change of two-phase fluid under different combination conditions.

[0024] The application also provides a COMSOL-based microfluidic detection device design system, which applies the design method of any one of the above, comprising: 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 determination;

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

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

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

[0030] Preferably, the workflow 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 rate 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;

[0034] Based on the mass conservation continuity equation and the Navier-Stokes equation, the control equation is constructed:

[0035]

[0036] Where, The gradient operator is represented by represents Laplace operator, mu represents dynamic viscosity of the fluid, and p represents channel pressure of the microfluidic chip on the fluid.

[0037] Preferably, the workflow of the model construction module comprises:

[0038] The size of the micropump and the distance between micropumps are determined based on the structural size of the microfluidic device and the physical parameters of the capillary pump, a CAD is used to construct a microfluidic device model and imported into COMSOL;

[0039] A two-dimensional graph is selected, a multi-physics field is added, liquid and air in the flow system are simulated using a two-phase flow in the MEMS module, parameter attributes are set, initial conditions and boundary conditions are used to constrain the equations, and multi-physics field coupling is carried out;

[0040] The microfluidic device model is meshed, and the mesh is refined according to the principle of fluid dynamics;

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

[0042] The influence of different parameter combinations of contact angle, micropump and fluid viscosity channel array on fluid velocity is considered, the parameter combination is adjusted according to the requirements and simulation results, and the volume change of the two-phase fluid under different combination conditions is analyzed.

[0043] Compared with the prior art, the beneficial effects of the present application are:

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

[0045] The present application considers the physical properties such as liquid viscosity and density in the microfluidic model simulation, considers different geometric structures, different geometric sizes of micropumps, and considers the influence of different substrate materials (hydrophilicity, surface charge, chemical stability and mechanical strength, etc. Physicochemical properties) on the performance of the microfluidic model. A single parameter can be changed, and the overall influence of the parameter on the fluid model can be independently studied.

[0046] The present application uses a two-dimensional model to approximately simulate a three-dimensional microfluidic structure, combines actual experiments with simulation experiments, provides a high-value theoretical reference for experimental research, and facilitates the adjustment and optimization of the device in actual experiments. BRIEF DESCRIPTION OF DRAWINGS

[0047] In order to more clearly illustrate the technical solutions of the present application, the following briefly introduces the drawings needed in the embodiments. Obviously, the drawings described below only show some of the embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0048] Figure 1 The method flowchart of the embodiment of the present application is shown in the figure.

[0049] Figure 2 The microfluidic device model of the embodiment of the present application is shown in the figure.

[0050] Figure 3 The grid division of the model of the embodiment of the present application is shown in the figure.

[0051] Figure 4 The volume fraction of the microfluidic device of the embodiment of the present application at time 0s is shown in the figure.

[0052] Figure 5 The volume fraction change of the microfluidic device of the embodiment of the present application at time 0.1s is shown in the figure.

[0053] Figure 6 The volume fraction change of the microfluidic device of the embodiment of the present application at time 1.85s is shown in the figure.

[0054] Figure 7 The liquid flow rate of the embodiment of the present application is shown in the figure.

[0055] Figure 8 The liquid pressure of the embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0056] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0057] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0058] Embodiment one

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

[0060] ​S1. Determine the structural dimensions of the microfluidic device, taking the liquid flow rate in the microfluidic device as the control target.

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

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

[0063] S3. Use the Navier-Stokes equations to describe momentum transfer and combine them with the mass conservation and continuity equations to establish the governing equations for fluid motion.

[0064] In this example, the Navier-Stokes equations are used to describe momentum transfer, including surface tension and mass conservation. A redesigned level set method is used to represent the separation between air and fluid. The mass conservation and continuity equations are combined to establish the governing equations for fluid motion, enabling simulation of fluid flow within the device. For a liquid in static equilibrium, the capillary surface Laplace and Young's equations are defined.

[0065] Construct the continuity equation for mass conservation:

[0066]

[0067] Wherein, ρ represents the fluid density, u represents the flow rate 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. represents the net outflow mass of the fluid, Indicates that mass decreases over time;

[0068] In addition to following the law of conservation of mass, fluids in microfluidic chips should also follow the law of conservation of momentum, which means that the rate of change of the fluid's momentum with time is equal to the sum of the external forces acting on it, that is:

[0069]

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

[0071] Considering that the inlet of the microfluidic device is a fluid inlet, the inlet capillary pressure and initial phase pressure are:

[0072]

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

[0074] The control equation is constructed based on mass conservation continuity equation and Navier-Stokes equation:

[0075]

[0076]

[0077] wherein, represents gradient operator, represents Laplace operator, and μ represents dynamic viscosity of fluid.

[0078] S4. Based on the structure size of the microfluidic device, the physical parameters of the capillary pump and the control method, a micro-pump guided microfluidic model is constructed and simulated by COMSOL.

[0079] The method for constructing and simulating the micro-pump guided microfluidic model comprises: determining the size of the micro-pump and the distance between the micro-pumps based on the structure size 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 a two-dimensional graph, adding a multi-physics field, simulating the liquid and air in the flow system using the two-phase flow in the MEMS module, setting parameter attributes and using initial conditions and boundary conditions to constrain the equations, and performing multi-physics field coupling; grid division is performed on the microfluidic device model, and the grid is super-fined according to the principle of fluid dynamics; add transient analysis, adjust the absolute tolerance, time step, termination method and criterion configuration in the solver according to the requirements, and obtain the volume fraction of the capillary filling process at different times through calculation and post-processing; considering the influence of different combinations of contact angle, micro-pump and fluid viscosity channel array parameters on fluid velocity, adjusting the parameter combination according to the requirements and simulation results, and analyzing the volume change of two-phase fluid under different combination conditions.

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

[0081] Δp=p l -p g =γ 1g (k1+k2)

[0082] wherein p lp represents liquid pressure g p represents gas pressure; Young equation involves solid-liquid γ ls , liquid-gas γ lg and gas-solid γ gs surface tension and contact angle θ at solid-liquid-gas:

[0083] γ 1g cosθ+γ ls =γ gs

[0084] When the contact angle reaches the critical advancing angle value θ α , the stop valve cannot be blocked. The analytical expression of the critical pressure can be obtained:

[0085]

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

[0087] S5. According to the simulation results, the parameters of the microfluidic model are adjusted, and the design of the microfluidic device is completed.

[0088] Example Two

[0089] In this embodiment, a COMSOL-based microfluidic detection device design system 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 determines the structural size of the microfluidic device with the liquid flow velocity in the microfluidic device as the control target.

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

[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 workflow of the equation construction module includes: constructing the mass conservation continuity equation:

[0094]

[0095] where ρ represents the fluid density, u represents the flow rate of the liquid to be tested 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] in, 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] The model building module uses COMSOL to construct a micropump-guided microfluidic model and perform simulation based on the structural dimensions of the microfluidic device, the physical parameters of the capillary pump, and the control method.

[0099] The workflow of the model building module includes: determining the size and spacing of the micropumps based on the structural dimensions of the microfluidic device and the physical parameters of the capillary pumps, building a microfluidic device model using CAD, and importing it into COMSOL; selecting a two-dimensional figure, adding multiphysics fields, using the two-phase flow in the MEMS module to simulate the liquid and air in the flow system, setting parameter properties, and using initial and boundary conditions to constrain the equations, and performing multiphysics coupling; meshing the microfluidic device model and ultra-refining the mesh according to fluid dynamics principles; adding transient analysis, adjusting the absolute tolerance, time step, termination method, and criterion configuration in the solver as needed, and obtaining the volume fraction of the capillary filling process at different times through calculation and post-processing. Considering the impact of different contact angle, micropump, and fluid viscosity channel array parameter combinations on fluid velocity, the parameter combinations are adjusted according to needs and simulation results, and the volume changes of the two-phase flow under different combination conditions are analyzed.

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

[0101] Example 3

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

[0103] In COMSOL, the "2D" spatial dimension was selected in the "Model Wizard" to simulate the novel microfluidic detection device using a 2D model. The "laminar flow SPF" model was used to simulate the fluid flow model, and the "phase field PF" model was used to simulate the interaction between liquid and air.

[0104] Create a geometric model. Design the microfluidic device based on fluid dynamics principles and design experience and use AutoCAD software to draw the two-dimensional structure of the device. Figure 2As shown, the whole is rectangular, the left side of the distribution of liquid inlet channel, capillary pump area is distributed on the right side of the inlet channel, pumping fluid function, and then to the right side of the detection of the detection of nanometer hole array sensor, the rightmost side of the fluid control area distributed capillary stop valve. In the microfluidic simulation model, the liquid and air are described as two different fluids, the model is mainly divided into the initial air occupied capillary pump area, and the liquid occupies the guide inlet, the main control parameters are the geometry and size of the capillary pump, 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 initial state of the air occupying the entire microfluidic device in the actual experimental environment. According to the design requirements, call or create liquid materials, and set the liquid in the channel inlet;

[0106] In the "laminar spf" physical field, the fluid environment is set, and the equation is constrained by the initial condition and the boundary condition, which includes the fluid attribute, the wall and the initial value. Set the inlet, select the leftmost inlet boundary of the model, set the outlet, select the lower right boundary of the model, and set the initial pressure.

[0107] As Figure 3 described, the microfluidic device model is meshed, the COMSOL built-in meshing function can be used, the "user controlled mesh" is selected, the "fluid dynamics" is calibrated, the mesh refinement predefinition is set according to the design accuracy requirement, and the "free triangular network" is used for mesh refinement, and then the mesh is generated.

[0108] In the "phase field pf", the two flowing phases of air and liquid are set by "initial value", the "wet wall" is set and the contact angle is adjusted to adjust the interaction between the liquid and the microfluidic device. In the "multi-physical field", the coupled fluid of the whole model is input, and the experimental condition parameters such as dynamic viscosity, density, temperature, etc. are input.

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

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

[0111] The above described embodiments are only to illustrate the preferred modes of the present application, and are not intended to limit the scope of the present application. Any modification and improvement made by those skilled in the art to the technical solutions of the present application without departing from the design spirit of the present application shall fall within the protection scope of the present application as defined by the claims.

Claims

1. A design method for a microfluidic detection device based on COMSOL, characterized in that: The following steps are involved: Taking the liquid flow rate 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 measurements; The Navier-Stokes equations are used to describe momentum transfer, and the mass conservation and continuity equations are combined to establish the governing equations for fluid motion. Based on the structural dimensions of the microfluidic device, the physical parameters of the capillary pump, and the control method, a microfluidic model guided by a micropump was constructed using COMSOL and simulated; Adjust the parameters of the microfluidic model based on the simulation results to complete the design of the microfluidic device; Methods for constructing a micropump-guided microfluidic model and performing simulations include: The size of the micropump and the spacing between the micropumps are determined based on the structural dimensions of the microfluidic device and the physical parameters of the capillary pump, and a microfluidic device model is constructed using CAD and imported into COMSOL; Select a 2D graph, add multiphysics, use the two-phase flow in the MEMS module to simulate the liquid and air in the flow system, set parameter properties, constrain the equations using initial conditions and boundary conditions, and perform multiphysics coupling. The microfluidic device model is meshed and the mesh is ultra-fine according to the principles of fluid dynamics; Add transient analysis and adjust the absolute tolerance, time stepping, termination method, and criterion configuration of the solver as needed. Obtain the volume fraction of the capillary filling process at different times through calculation and post-processing. Considering the impact of different contact angles, micropumps, and fluid viscosity channel array parameter combinations on fluid velocity, the parameter combinations are adjusted according to demand and simulation results, and the changes in two-phase flow volume under different combination conditions are analyzed.

2. The design method of a microfluidic detection device based on COMSOL according to claim 1, characterized in that: The method of constructing the control equation includes: Construct the continuity equation for mass conservation: Wherein, ρ represents the fluid density, u represents the flow rate 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; The control equation is constructed based on the mass conservation continuity equation and the Navier-Stokes equation: in, 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. A design system for a microfluidic detection device based on COMSOL, wherein the design system applies the design method according to any one of claims 1 to 2, characterized in that: include: a size determination module, a parameter determination module, an equation building module, a model building module, and a parameter adjustment module; The size determination module determines the structural size of the microfluidic device by taking the liquid flow rate in the microfluidic device as a control target; The parameter determination module determines the physical parameters of the capillary pump through experimental measurements; The equation building module uses the Navier-Stokes equations to describe momentum transfer and combines them with the mass conservation and continuity equations to establish the governing equations for fluid motion; The model building module uses COMSOL to build a microfluidic model guided by a micropump and perform simulation 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 adjust the parameters of the microfluidic model according to the simulation result feedback to complete the design of the microfluidic device.

4. The design system of a microfluidic detection device based on COMSOL according to claim 3, characterized in that: The workflow of the equation building module includes: Construct the continuity equation for mass conservation: Wherein, ρ represents the fluid density, u represents the flow rate 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; The control equation is constructed based on the mass conservation continuity equation and the Navier-Stokes equation: in, 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.

5. The design system of a microfluidic detection device based on COMSOL according to claim 3, characterized in that: The workflow of the model building module includes: The size of the micropump and the spacing between the micropumps are determined based on the structural dimensions of the microfluidic device and the physical parameters of the capillary pump, and a microfluidic device model is constructed using CAD and imported into COMSOL; Select a 2D graph, add multiphysics, use the two-phase flow in the MEMS module to simulate the liquid and air in the flow system, set parameter properties, constrain the equations using initial conditions and boundary conditions, and perform multiphysics coupling. The microfluidic device model is meshed and the mesh is ultra-fine according to the principles of fluid dynamics; Add transient analysis and adjust the absolute tolerance, time stepping, termination method, and criterion configuration of the solver as needed. Obtain the volume fraction of the capillary filling process at different times through calculation and post-processing. Considering the impact of different contact angles, micropumps, and fluid viscosity channel array parameter combinations on fluid velocity, the parameter combinations are adjusted according to demand and simulation results, and the changes in two-phase flow volume under different combination conditions are analyzed.

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