Multifunctional modular flow rheological mixing method and device based on controllable flow field

Abstract

The application discloses a multifunctional modular rheological mixing method and device based on a controllable flow field. The method is to fully mix a solution by using a stretching flow generated by expansion and contraction of a converging flow channel in a mixing cavity or a shearing flow generated by a wall speed difference of a flat plate flow channel. A pressure sensor on the mixing cavity and a load sensor on a push-pull shaft record the solution pressure in the mixing cavity and the thrust on the push-pull shaft in real time, respectively. The obtained data are used to solve the current viscous resistance, shear viscosity and shear rate, thereby providing an optimization basis for a material formula, a flow field structure and / or a mixing frequency of the next solution mixing. The device comprises an upper cavity, a lower cavity, a push-pull rod, a push-pull shaft, a pressure sensor and a load sensor. The upper cavity and the lower cavity are matched to form the mixing cavity. The push-pull shaft is arranged in the mixing cavity. The push-pull shaft is connected with the push-pull rod. One end of the push-pull rod is provided with the load sensor. A plurality of pressure sensors are arranged on one side of the mixing cavity.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of blending forming and rheological property measurement, in particular to a multifunctional modular rheological mixing method and device based on controllable flow field. BACKGROUND

[0002] In today's society development and technological progress, rheological property measurement, material mixing and different flow field change law usually need to rely on independent equipment for operation, which increases the equipment cost, operation complexity and energy consumption. Therefore, it has important application value to develop a controllable flow field composite device integrated with a rheometer and a mixing instrument to realize the integrated processing of rheological property measurement and mixing under different flow fields.

[0003] Rheological property measurement is an important means to study the rheological behavior of materials, which can provide the mechanical properties and viscosity characteristics of materials. However, the traditional rheometer generally needs to be operated separately, and strictly requires the same material category, which is isolated from material mixing, which also leads to the fact that the rheometer cannot realize real-time monitoring and improvement of solution mixing. On the other hand, material mixing is a process of dispersing and mixing different materials, which is widely used in rubber, plastic, chemical and other fields. However, the traditional mixing instrument also has strict requirements for solution category, and the traditional mixing instrument is difficult to mix solutions with extremely high molecular weight, poor melt flowability, poor heat and mass transfer effect, and the mixing instrument does not have the ability to measure the rheological properties, so it cannot adjust the dispersion and mixing ability of the solution in the flow field and the molecular chain disentanglement ability based on the rheological properties, ultimately leading to the fact that the method of optimizing material formula or improving flow field structure cannot be used to solve the above problems. Therefore, it has important application value to develop a controllable flow field composite device integrated with a rheometer and a mixing instrument to realize the integrated processing of rheological property measurement and material mixing of high molecular composite solution, high molecular composite melt, high molecular hydrogel and other solutions under different flow fields. SUMMARY

[0004] The present application aims to overcome the shortcomings of the prior art and provide a multifunctional modular rheological mixing method based on controllable flow field, which can realize the integrated processing of rheological property measurement and material mixing under different flow fields, and the rheological property parameters obtained by measurement can be used to further optimize the material formula, process structure or mixing times and other parameters in the next processing process.

[0005] Another object of the present application is to provide a multifunctional modular rheological mixing device based on controllable flow field for realizing the above method, which integrates the advantages of rheometer and mixing instrument, and can realize the integrated processing of rheological property measurement and material mixing under different flow fields.

[0006] The technical scheme of the present application is: based on the controllable flow field of the multifunctional modular flow rheological mixing method, by setting the push-pull shaft in the mixing cavity, under the reciprocating motion of the push-pull shaft, the solution reciprocates in the mixing cavity with periodic shape change, and the solution is fully mixed by using the stretching flow generated by the expansion-constriction of the convergent flow channel in the mixing cavity or the shear flow generated by the wall speed difference of the flat plate flow channel, so that the effect of continuous stretching flow or shear flow is obtained, and the fully mixed solution is obtained under the action of the circulating stretching flow or shear flow; wherein, according to the different cross-sectional shapes of the push-pull shaft, the convergent flow channel is formed between the push-pull shaft with arc surface such as circular cross section and the inner wall of the mixing cavity, and the flat plate flow channel is formed between the push-pull shaft with plane such as rectangular cross section and the inner wall of the mixing cavity; in the above dispersion mixing process, the solution experiences the pulsating dispersion process of dispersion, reciprocation, redispersion and re-reciprocation, so that the molecular chain of the solution is gradually opened and tangled, and the molecular chain and the particles are fully dispersed and mixed;

[0007] In the process of dispersing and mixing the solution, the pressure sensor arranged on the mixing cavity and the load sensor arranged on the push-pull shaft respectively record the solution pressure in the mixing cavity and the thrust on the push-pull shaft in real time, and the obtained data is used to solve the viscous resistance of the solution on the surface of the push-pull shaft and the shear viscosity and shear rate of the solution when the current push-pull shaft is used, thereby providing an optimization basis for the material formula, flow field structure and / or mixing times of the next solution mixing.

[0008] In this process, the rheological performance parameters such as the viscous resistance on the surface of the push-pull shaft, the shear viscosity and shear rate of the solution under the current state are solved by using the obtained data, then the influence law of the stretching times, molecular weight, solid content, push-pull shaft structure and other factors on the rheological properties of the solution is studied, the critical point of the solution from heterogeneous state to complete dispersion and molecular chain disentanglement is determined, and the material formula, flow field structure and mixing times are optimized in real time to meet the requirements of full dispersion and molecular chain disentanglement of different solution systems.

[0009] In the above method, the specific process of solving the viscous resistance of the solution on the surface of the push-pull shaft and the shear viscosity and shear rate of the solution when the current push-pull shaft is used by using the obtained data is as follows:

[0010] To establish a mathematical simplified model inside the flow field, firstly, the solution in the mixing cavity is set as an isothermal, steady-state laminar flow and the weight is ignored; secondly, compared with the viscous shear force, the inertial force of the solution caused by acceleration is also ignored; thirdly, the radius R of the push-pull shaft is much larger than the minimum gap through which the solution can pass, so there is a slip between the solution and the cavity wall; in addition, a direct coordinate system (x, y, z) is established for the example of a cylindrical push-pull shaft to represent the position of each point inside the mixing cavity; in the direct coordinate system (x, y, z), the origin O of the direct coordinate system is set as the internal center of the push-pull shaft, and the entire direct coordinate system moves together with the push-pull shaft reciprocating; the x-axis is set along the movement direction of the push-pull shaft, and the positive direction is the opposite direction of the movement of the push-pull shaft; the y-axis is perpendicular to the x-axis, and the positive direction is directly to the upper cavity wall of the mixing cavity; the z-axis is used by the right hand four fingers to turn from the x-axis to the y-axis in the counterclockwise direction, and the direction of the thumb is the positive direction of the z-axis; but because in the z-axis direction, the cavity cross-sectional shape is only elongated without changing, so under the condition of certain x and y coordinates, the velocity and pressure of the solution will not change much along the z-axis coordinate, so only the x and y axis directions are considered;

[0011] In this mathematical model, the width of the mixing cavity along the z-axis direction is B; the straight line distance from x2 to x1 is L; when the horizontal coordinate is x, the distance from the position of the push-pull shaft structure surface to the shaft is Y(x), the distance from the position of the solution to be measured to the x-axis is y (y≥Y(x)), and y1=y2; the cross-sectional area perpendicular to the x-axis when the horizontal coordinate is x is A; the viscous resistance of the push-pull shaft surface is F tui ; the consistency coefficient is k; the power-law index is n;

[0012] When the rheological mixing device is running, record the pressure values P1, P2 measured by the pressure sensor and the thrust F of the push-pull shaft measured by the load sensor, and then calculate the current solution shear viscosity η 剪 , the calculation process is as follows:

[0013] Substitute the pressure values P1, P2 and the thrust F of the push-pull shaft into the basic equation of fluid mechanics to simplify formula (1),

[0014]

[0015] Double integrate formula (1) with respect to x and y and multiply by the width B of the rheological mixing cavity along the z-axis to obtain formula (2), where x is the coordinate value of the solution on the x-axis (the x-axis is the movement direction of the push-pull shaft), y is the coordinate value of the solution on the y-axis (the y-axis is the positive direction directly to the upper cavity wall of the mixing cavity), τ xx is the shear stress of the solution at the corresponding coordinates (x, y) along the y-axis direction;

[0016]

[0017] Where P1 is the pressure value measured by the pressure sensor at the cross section of x1 coordinate and perpendicular to the x axis, and P2 is the pressure value measured by the pressure sensor at the cross section of x2 coordinate; B is the width of the rheological mixing cavity along the z axis; Y(x) is the distance from the surface of the push-pull shaft structure to the x axis when the horizontal coordinate is x; y(x) is the distance from the position of the solution to be measured to the x axis when the horizontal coordinate is x (y(x)≥Y(x)), and y(x1)=y(x2); L is the straight line distance from x2 to x1; F is the pushing force of the push-pull shaft; F tui is the viscous resistance of the surface of the push-pull shaft; τ yx is the shear stress of the solution at the coordinate (x, y) along the x axis.

[0018] Then, the function relationship between the shear rate and the parameters of each sensor is established by forming an equation group with the power law equation and formula (2), and the shear rate is equal to the velocity gradient, so the velocity gradient du / dy of the solution at the coordinate (x, y) is solved:

[0019]

[0020] Where γ is the shear rate, k is the consistency coefficient, and n is the power law index.

[0021] According to the force balance equation of the solution in the x axis direction, the tensile stress σ x of the solution in the x axis direction at the coordinate (x, y) is solved.

[0022] The velocity u(x, y) of the solution at the coordinate (x, y) is further solved by integrating y in formula (3):

[0023]

[0024] Where Then, the numerical solution of the viscous resistance F tui of the surface of the push-pull shaft is solved through the characteristic that the flow rates through different cross sections are the same, i.e. A1u(x1, y)=A2u(x2, y);

[0025] Finally, the shear viscosity η 剪 of the solution at the coordinate (x, y) is solved through formula (3) and the power law equation.

[0026]

[0027] The numerical values of the shear viscosity η 剪 , the shear rate γ, and the viscous resistance F tui of the surface of the push-pull shaft are finally obtained.

[0028] The solution is a dilute solution, a semi-dilute solution, a concentrated solution, a melt, a polyelectrolyte, or a gel.

[0029] The application is a multifunctional modular rheological mixing device based on controllable flow field for the above-mentioned rheological mixing method, comprising an upper cavity, a lower cavity, a push-pull rod, a push-pull shaft, a pressure sensor and a load sensor. The upper cavity and the lower cavity cooperate to form a mixing cavity, the push-pull shaft is arranged in the mixing cavity, and a gap for the solution to pass through is left between the surface of the push-pull shaft and the inner wall of the mixing cavity. The two sides of the push-pull shaft are connected with the push-pull rod, the two ends of the push-pull rod are installed between the upper cavity and the lower cavity, one end of the push-pull rod is connected with a load device, and a load sensor is arranged at the connection between the push-pull rod and the load device. A plurality of pressure sensors are distributed on one side of the mixing cavity. The pressure sensor is used to detect the pressure in the mixing cavity in real time during the mixing process, and the load sensor is coaxially arranged with the push-pull shaft and is used to detect the thrust of the push-pull shaft in real time during the mixing process.

[0030] The push-pull shaft reciprocates in the mixing cavity, and a circulating flow field region is formed between the push-pull shaft and the mixing cavity, which serves as a sealed working interval. The push-pull shaft cooperates with the mixing cavity, and when the push-pull shaft reciprocates forward and backward, the mixing cavity forms a front chamber and a rear chamber on the front and rear sides of the push-pull shaft, and the volumes of the front and rear chambers change periodically.

[0031] The flow field region is a shear flow field region or a stretching flow field region.

[0032] The cross section of the push-pull shaft is circular, rectangular, trapezoidal or pentagonal.

[0033] The push-pull rod comprises a front supporting push-pull rod and a rear supporting push-pull rod, and the front supporting push-pull rod and the rear supporting push-pull rod are respectively detachably connected with the two sides of the push-pull shaft. By disassembling the front and rear supporting push-pull rods, different cross-sectional shapes or sizes of the push-pull shaft can be replaced according to actual needs, and the specific connection mode adopts the conventional installation mode of existing similar push-pull shafts.

[0034] The connecting surface of the upper cavity and the lower cavity is also provided with a gasket and a packing, and the gasket and the packing are respectively distributed on the outer periphery of the mixing cavity. The packing serves as a sealing device to prevent the solution from leaking due to internal pressure. The gasket has a buffering and sealing effect and can also be used to adjust the gap between the upper and lower cavities.

[0035] The upper cavity top is also provided with a gland and a visualization window, which are distributed above the mixing cavity respectively.

[0036] Compared with the prior art, the present application has the following beneficial effects:

[0037] In the present multifunctional modular rheological mixing method and device based on controllable flow field, periodic reciprocating motion is used to provide a controllable flow field for the solution, which is conducive to obtaining a solution that is fully dispersed and mixed and has molecular chain disentanglement under different flow fields. At the same time, the data of the solution during mixing are recorded in real time by sensors (including pressure sensors and load sensors), and after analysis, the material formula, flow field type, mixing times and other parameters required by different solutions to meet the conditions of full dispersion and full disentanglement can be determined, thereby optimizing and improving the mixing effect of various solutions. Secondly, the flow field design of reciprocating motion makes the flowability of the solution in the mixing cavity uniform, avoiding local overheating or uneven mass transfer. With the real-time feedback of the sensors, the mixing times, push-pull rod speed, temperature rising temperature and other parameters can also be controlled to deal with molecular chain degradation and other performance problems.

[0038] The present multifunctional modular rheological mixing device based on controllable flow field integrates the characteristics of rheometer and mixer, forms a replaceable design and multifunctional modular design of equipment structure, realizes efficient and collaborative operation mode of measuring and processing of the rheological properties of high polymer composite solution, high polymer composite melt and high polymer hydrogel under different flow fields, closely combines the rheological property measurement under different flow fields and the material mixing process, realizes integrated operation of measurement and processing, and does not need to separate mixing and rheological test, saving time, experimental steps and material cost. BRIEF DESCRIPTION OF DRAWINGS

[0039] Fig. 1(a) is a schematic diagram of the principle of the stretching flow field in the dispersion mixing process in the mixing cavity of the present multifunctional modular rheological mixing device.

[0040] Fig. 1(b) is a schematic diagram of the principle of the shearing flow field in the dispersion mixing process in the mixing cavity of the present multifunctional modular rheological mixing device.

[0041] Figure 2 Fig. 2 is a schematic diagram of the principle of the present multifunctional modular rheological mixing device.

[0042] Figure 3 Fig. 3 is a schematic diagram of the principle of the present multifunctional modular rheological mixing device. Figure 2A-A direction cross-sectional view of figure 1.

[0043] Figure 4 B-B direction cross-sectional view of figure 1. Figure 2 B-B direction cross-sectional view of figure 1.

[0044] Figure 5 Structure diagram of mixing cavity.

[0045] Figure 6 A-A direction cross-sectional view of figure 1. Figure 5 A-A direction cross-sectional view of figure 1.

[0046] Figure 7 B-B direction cross-sectional view of figure 1. Figure 6 B-B direction cross-sectional view of figure 1.

[0047] Figure 8 Structure diagram when the cross section of the push-pull shaft is rectangular.

[0048] Figure 9 Structure diagram when the cross section of the push-pull shaft is trapezoidal.

[0049] Figure 10 Structure diagram when the cross section of the push-pull shaft is pentagonal.

[0050] Figure 11 Structure diagram when the cross section of the push-pull shaft is circular.

[0051] In the above figures, the components shown by the reference numerals are as follows:

[0052] 1 is the surface of the push-pull shaft, 2 is the position of the composite material to be measured in the solution, V is the running speed of the push-pull shaft, and F is the thrust of the push-pull shaft.

[0053] 3 is a packing, 4 is an upper cavity, 5 is a solution, 6 is a visualization window, 7 is a push-pull rod, 8 is a lower cavity, 9 is a push-pull shaft, 10 is a pressure sensor, 11 is a load sensor, 12 is a gland, and 13 is a gasket. DETAILED DESCRIPTION

[0054] The present application will be further described in detail below in conjunction with examples, but the embodiments of the present application are not limited thereto.

[0055] Example 1

[0056] This embodiment provides a multifunctional modular rheological mixing device based on controllable flow field, such as Figures 2 to 7As shown, the device comprises an upper cavity 4, a lower cavity 8, a push-pull rod 7, a push-pull shaft 9, a pressure sensor 10 and a load sensor 11. The upper cavity and the lower cavity cooperate to form a mixing cavity, the push-pull shaft is arranged in the mixing cavity, and a gap for the solution to pass through is left between the surface of the push-pull shaft and the inner wall of the mixing cavity. The two sides of the push-pull shaft are connected with the push-pull rod, the two ends of the push-pull rod are installed between the upper cavity and the lower cavity, one end of the push-pull rod is connected with a load device, and a load sensor is arranged at the connection between the push-pull rod and the load device. A plurality of pressure sensors are arranged on one side of the mixing cavity. The pressure sensor is used to detect the pressure in the mixing cavity in real time during the mixing process. The load sensor is coaxially arranged with the push-pull shaft and is used to detect the thrust of the push-pull shaft in real time during the mixing process. The connecting surface of the upper cavity and the lower cavity is further provided with a gasket 13 and a packing 3, and the gasket and the packing are respectively distributed on the outer periphery of the mixing cavity. The packing serves as a sealing device to prevent the solution from leaking out due to internal pressure. The gasket has a buffering and sealing effect and can also be used to adjust the gap between the upper cavity and the lower cavity. The upper cavity is further provided with a gland 12 and a visual window 6, and the gland and the visual window are respectively distributed above the mixing cavity. The gland is used to compress and install the upper cavity and the lower cavity. The visual window can be made of quartz glass and is arranged at a non-central position on the upper cavity. After the solution is added, the tightening and fixing condition of the gland can be observed through the visual window, so that a completely sealed mixing chamber is formed between the upper cavity and the lower cavity. During the process of dispersing and mixing the solution, the mixing process of the solution can be observed in real time through the visual window.

[0057] The push-pull shaft reciprocates in the mixing cavity, and a circulating flow field region is formed between the push-pull shaft and the mixing cavity, which serves as a sealed working interval. The push-pull shaft cooperates with the mixing cavity, and when the push-pull shaft reciprocates forward and backward, the mixing cavity forms a front chamber and a rear chamber on the front and rear sides of the push-pull shaft. The volumes of the front and rear chambers change periodically. The flow field region is a shear flow field region or a stretching flow field region.

[0058] The push-pull rod comprises a front supporting push-pull rod and a rear supporting push-pull rod, which are respectively detachably connected with the two sides of the push-pull shaft. By disassembling the front and rear supporting push-pull rods, different cross-sectional shapes or sizes of the push-pull shaft can be replaced according to actual needs. The specific connection method adopts the conventional installation method of existing similar push-pull shafts. Figures 8 to 11 As shown, the push-pull shafts with circular, rectangular, trapezoidal or pentagonal cross sections can be used.

[0059] Example 2

[0060] The present embodiment provides a multifunctional modular rheological mixing method based on controllable flow field, which is realized by the multifunctional modular rheological mixing device described in Example 1.

[0061] The method sets a push-pull shaft in the mixing cavity, and the solution reciprocates in the mixing cavity with periodically changing shape under the reciprocating action of the push-pull shaft. The solution is fully mixed by using the stretching flow generated by the expansion-constriction of the convergent flow channel or the shear flow generated by the wall speed difference of the flat plate flow channel in the mixing cavity, so that the effect of continuous stretching flow or shear flow is obtained, and the fully mixed solution is obtained under the action of the circulating stretching flow or shear flow. According to the different cross-sectional shapes of the push-pull shaft, the convergent flow channel is formed between the push-pull shaft with arc surface such as circular cross section and the inner wall of the mixing cavity (the stretching flow field formed is shown in Fig. 1(a)), and the flat plate flow channel is formed between the push-pull shaft with flat surface such as rectangular cross section and the inner wall of the mixing cavity (the shear flow field formed is shown in Fig. 1(b)). In the above dispersion mixing process, the solution experiences the pulsating dispersion process of dispersion, reciprocation, redispersion, and re-reciprocation, so that the molecular chain of the solution is gradually opened and tangled, and the molecular chain and the particles are fully dispersed and mixed. In the process of dispersing and mixing the solution, the pressure sensor arranged on the mixing cavity and the load sensor arranged on the push-pull shaft record the solution pressure in the mixing cavity and the thrust on the push-pull shaft in real time, respectively. The obtained data are used to solve the viscous resistance of the solution on the surface of the push-pull shaft and the shear viscosity and shear rate of the solution when the current push-pull shaft is used, so as to provide an optimization basis for the material formula, flow field structure and / or mixing times of the next solution mixing. In this process, the rheological performance parameters such as the viscous resistance of the push-pull shaft surface, the shear viscosity and shear rate of the solution under the current state are solved by using the obtained data, then the influence law of the stretching times, molecular weight, solid content, push-pull shaft structure and other factors on the rheological properties of the solution is studied, the critical point of the solution from heterogeneous state to complete dispersion and molecular chain untangling is determined, and thus the material formula, flow field structure and mixing times are optimized in real time to meet the requirements of full dispersion of different solution systems and full untangling of molecular chains.

[0062] The specific process of solving the viscous resistance of the solution on the surface of the push-pull shaft and the shear viscosity and shear rate of the solution when the current push-pull shaft is used by using the obtained data is as follows (the principle is shown in Fig. 1):

[0063] To establish a mathematical simplified model inside the flow field, firstly, the solution in the mixing cavity is set as an isothermal, steady-state laminar flow and the weight is ignored; secondly, compared with the viscous shear force, the inertial force of the solution caused by acceleration is also ignored; thirdly, the radius R of the push-pull shaft is much larger than the minimum gap through which the solution can pass, so there is a slip between the solution and the cavity wall; in addition, a direct coordinate system (x, y, z) is established for the example of a cylindrical push-pull shaft to represent the position of each point inside the mixing cavity; in the direct coordinate system (x, y, z), the origin O of the direct coordinate system is set as the internal center of the push-pull shaft, and the entire direct coordinate system moves together with the push-pull shaft reciprocating; the x-axis is set along the movement direction of the push-pull shaft, and the positive direction is the opposite direction of the movement of the push-pull shaft; the y-axis is perpendicular to the x-axis, and the positive direction is directly to the upper cavity wall of the mixing cavity; the z-axis is used by the right hand four fingers to turn from the x-axis to the y-axis in the counterclockwise direction, and the direction of the thumb is the positive direction of the z-axis; but because in the z-axis direction, the cavity cross-sectional shape is only elongated without changing, so under the condition of certain x and y coordinates, the velocity and pressure of the solution will not change much along the z-axis coordinate, so only the x and y axis directions are considered;

[0064] In this mathematical model, the width of the mixing cavity along the z-axis direction is B; the straight line distance from x2 to x1 is L; when the horizontal coordinate is x, the distance from the position of the push-pull shaft structure surface to the shaft is Y(x), the distance from the position of the solution to be measured to the x-axis is y (y≥Y(x)), and y1=y2; the cross-sectional area perpendicular to the x-axis when the horizontal coordinate is x is A; the viscous resistance of the push-pull shaft surface is F tui ; the consistency coefficient is k; the power-law index is n;

[0065] When the rheological mixing device is running, record the pressure values P1, P2 measured by the pressure sensor and the thrust F of the push-pull shaft measured by the load sensor, and then calculate the current solution shear viscosity η 剪 , the calculation process is as follows:

[0066] Substitute the pressure values P1, P2 and the thrust F of the push-pull shaft into the basic equation of fluid mechanics to simplify formula (1),

[0067]

[0068] Double integrate formula (1) with respect to x and y and multiply by the width B of the rheological mixing cavity along the z-axis to obtain formula (2), where x is the coordinate value of the solution on the x-axis (the x-axis is the movement direction of the push-pull shaft), y is the coordinate value of the solution on the y-axis (the y-axis is the positive direction directly to the upper cavity wall of the mixing cavity), τ xx is the shear stress of the solution at the corresponding coordinates (x, y) along the y-axis direction;

[0069]

[0070] Where P1 is the pressure value measured by the pressure sensor at the cross section of x1 coordinate and perpendicular to the x axis, and P2 is the pressure value measured at the cross section of x2 coordinate; B is the width of the rheological mixing cavity along the z axis; Y(x) is the distance from the position of the push-pull shaft structure surface to the x axis when the horizontal coordinate is x; y(x) is the distance from the position of the solution to the x axis when the horizontal coordinate is x (y(x)≥Y(x)), and y(x1)=y(x2); L is the straight line distance from x2 to x1; F is the thrust of the push-pull shaft; F tui is the viscous resistance of the push-pull shaft surface; τ yx is the shear stress of the solution at the coordinate (x, y) along the x axis.

[0071] Then the function relationship between the shear rate and the parameters of each sensor is established by forming an equation group with the power law equation and formula (2), and the shear rate is equal to the velocity gradient, so the velocity gradient du / dy of the solution at the coordinate (x, y) is solved:

[0072]

[0073] Where γ is the shear rate, k is the consistency coefficient, and n is the power law index.

[0074] According to the force balance equation of the solution in the x axis direction, the tensile stress σ x of the solution at the coordinate (x, y) along the x axis is solved.

[0075] The velocity u(x, y) of the solution at the coordinate (x, y) is further solved by integrating y in formula (3):

[0076]

[0077] Where Then the numerical solution of the viscous resistance F tui of the push-pull shaft surface is solved through the characteristics that the flow rates through different cross sections are the same, i.e. A1u(x1, y)=A2u(x2, y);

[0078] Finally, the shear viscosity η 剪 of the solution at the coordinate (x, y) is solved through formula (3) and the power law equation.

[0079]

[0080] The numerical values of the shear viscosity η 剪 , the shear rate γ, and the viscous resistance F tui of the push-pull shaft surface are ultimately obtained.

[0081] The solution is a dilute solution, a semi-dilute solution, a concentrated solution, a melt, a polyelectrolyte, or a gel.

[0082] As described above, the application can be implemented better, and the above-mentioned embodiments are only the preferred embodiments of the application, but not to limit the scope of the application; that is, all equivalent changes and modifications made according to the content of the application are covered by the scope of the claims of the application.

Claims

1. A multifunctional modular rheological mixing method based on a controllable flow field, characterized in that: By arranging a push-pull shaft in the mixing chamber, the solution reciprocates in the mixing chamber whose shape changes periodically under the reciprocating motion of the push-pull shaft, and the solution is fully mixed by utilizing the extensional flow generated by the expansion-contraction of the convergent flow channel formed in the mixing chamber or the shear flow generated by the wall velocity difference of the flat flow channel, thereby obtaining the effect of continuous extensional flow or shear flow, and obtaining a fully mixed solution under the action of the cyclic extensional flow or shear flow; During the process of dispersing and mixing the solution, the pressure sensor installed on the mixing chamber and the load sensor installed on the push-pull shaft respectively record the solution pressure in the mixing chamber and the thrust on the push-pull shaft in real time. The obtained data are used to solve the viscous resistance of the solution on the push-pull shaft surface, the shear viscosity and the shear rate of the solution when the current push-pull shaft is used. Based on this, a basis for optimizing the material formula, flow field structure and / or mixing times of the next solution mixing is provided; The specific process of using the obtained data to solve the viscous resistance of the solution on the push-pull shaft surface, the shear viscosity of the solution, and the shear rate when using the current push-pull shaft is as follows: Record the pressure values ​​P1 and P2 measured by the pressure sensor and the thrust F of the push-pull shaft measured by the load sensor, and then calculate the current solution shear viscosity η 剪 , the calculation process is as follows: Substituting the pressure value P1, the pressure value P2 and the thrust F of the push-pull shaft into the basic equation of fluid mechanics, it is simplified to formula (1): ； (1) Formula (1) is used to perform double integration of x and y and then multiply it by the width B of the rheological mixing chamber along the z axis to obtain formula (2), where x is the coordinate value of the solution on the x axis, the x axis is the movement direction of the push-pull axis, y is the coordinate value of the solution on the y axis, the y axis is the positive direction directly pointing to the upper cavity wall of the mixing chamber, τ xx is the shear stress of the solution along the y-axis at the corresponding coordinate (x, y); ； (2) The pressure sensor measures the pressure value of the solution at the cross section perpendicular to the x-axis at the x1 coordinate as P1, and the pressure value at the cross section at the x2 coordinate as P2; B is the width of the rheological mixing chamber along the z-axis; Y(x) is the distance from the position of the push-pull shaft structure surface to the x-axis when the horizontal coordinate is x; y(x) is the distance from the position of the solution to be tested to the x-axis when the horizontal coordinate is x; y(x) ≥ Y(x), and ; L is the straight line distance from x2 to x1; F is the thrust of the push-pull axis; F tui is the viscous resistance on the push-pull shaft surface; τ yx is the shear stress of the solution along the x-axis at the corresponding coordinate (x, y); Then, the power law equation and formula (2) are combined to form a system of equations to establish the functional relationship between the shear rate and the various sensor parameters. Since the shear rate is equal to the velocity gradient, the velocity gradient du / dy of the solution at the (x, y) coordinate is solved: ；(3) Where γ is the shear rate, k is the consistency coefficient, and n is the power law exponent; According to the force balance equation of the solution in the x-axis direction, the tensile stress σ of the solution along the x-axis direction at the (x, y) coordinate is solved. x ; The velocity u(x,y) of the solution at the (x,y) coordinate can be further solved by performing a definite integral on y using formula (3): ； (4) in , , then the flow through different cross sections has the same characteristics, that is , solve the viscous resistance F on the push-pull shaft surface tui Numerical solution of ; Finally, the shear viscosity η of the solution at the (x, y) coordinate is solved by formula (3) and the power law equation: 剪 : ； (5) Finally, the shear viscosity η is obtained 剪 , shear rate γ, viscous resistance F on the push-pull shaft surface tui The numerical value of .

2. The multifunctional modular rheological mixing method based on controllable flow field according to claim 1, characterized in that: The solution is a dilute solution, a semi-dilute solution, a concentrated solution, a melt, a polyelectrolyte or a gel.

3. A multifunctional modular rheological mixing device based on a controllable flow field for implementing the rheological mixing method according to claim 1 or 2, characterized in that: It includes an upper cavity, a lower cavity, a push-pull rod, a push-pull shaft, a pressure sensor and a load sensor. The upper cavity and the lower cavity cooperate to form a mixing chamber. The push-pull shaft is arranged in the mixing chamber, and a gap is left between the surface of the push-pull shaft and the inner wall of the mixing chamber for the solution to pass through. Push-pull rods are connected to both sides of the push-pull shaft. The two ends of the push-pull rods are installed between the upper cavity and the lower cavity. One end of the push-pull rod is connected to an external load device, and a load sensor is provided at the connection between the push-pull rod and the load device. Several pressure sensors are distributed on one side of the mixing chamber.

4. The multifunctional modular rheological mixing device based on a controllable flow field according to claim 3, characterized in that: The push-pull shaft reciprocates in the mixing chamber, and a circulating flow field area is formed between the push-pull shaft and the mixing chamber.

5. The multifunctional modular rheological mixing device based on controllable flow field according to claim 4, characterized in that: The flow field region is a shear flow field region or a stretching flow field region.

6. The multifunctional modular rheological mixing device based on a controllable flow field according to claim 3, characterized in that: The cross section of the push-pull shaft is circular, rectangular, trapezoidal or pentagonal.

7. The multifunctional modular rheological mixing device based on a controllable flow field according to claim 3, characterized in that: The push-pull rod comprises a front support push-pull rod and a rear support push-pull rod, and the front support push-pull rod and the rear support push-pull rod are detachably connected to both sides of the push-pull shaft respectively.

8. The multifunctional modular rheological mixing device based on a controllable flow field according to claim 3, characterized in that: The connection surface between the upper cavity and the lower cavity is further provided with a gasket and a packing, and the gasket and the packing are respectively distributed on the periphery of the mixing cavity.

9. The multifunctional modular rheological mixing device based on a controllable flow field according to claim 3, characterized in that: A pressure cover and a visualization window are also provided on the top of the upper cavity, and the pressure cover and the visualization window are respectively distributed above the mixing cavity.

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