Multi-shaft differential stirring structure optimization method applied to adhesive production

Abstract

The invention discloses a method for optimizing a multi-shaft differential stirring structure applied to adhesive production, and relates to the technical field of optimization of stirring reactors for high-viscosity materials, the multi-shaft differential stirring structure comprises a multi-shaft differential stirring kettle, the multi-shaft differential stirring kettle is composed of an eccentric tooth-shaped dispersing shaft and an axial single-paddle shaft, wherein the impeller of the eccentric shaft and the impeller of the axial single paddle shaft respectively adopt a tooth-shaped disc type impeller and an axial flow single-blade paddle impeller; the multi-shaft differential stirring kettle is applied to high-viscosity fluid with different filler ratios, the eccentric tooth-shaped dispersing shaft serves as a main shaft, the axial single-paddle shaft serves as an auxiliary shaft, and the rotating speed ratio of the main shaft to the auxiliary shaft is set to be 1-3. Therefore, by the adoption of the multi-shaft differential stirring structure optimization method applied to adhesive production, the material mixing effect is enhanced, the mixing time is effectively shortened, meanwhile, low power consumption per unit volume is kept, reference is provided for optimization design of high-viscosity fluid and adhesive synthesis reactors, and industrial production efficiency and product quality can be improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of optimization of agitated reactors for high viscosity materials, in particular to a multi-shaft differential stirring structure optimization method applied to adhesive production. BACKGROUND

[0002] As a key functional material, adhesives are widely used in modern industry, covering multiple fields such as construction, automobiles, electronics, aerospace and biomedicine. With the increasing demand for high-performance adhesives, multi-component components such as nanofillers, toughening agents and conductive particles are commonly introduced into their formulations, which puts higher requirements on the uniformity of dispersion in the reactor. Studies have shown that the local dispersion state of fillers in the adhesive matrix directly affects the interfacial bonding strength, thermal stability and electrical conductivity of key properties, and the structural design of the agitated reactor, as the core device of the synthesis process, has a decisive influence on the dispersion effect.

[0003] At present, for the agitated reactor of high viscosity material, researchers have proposed many improvement measures and optimization methods. These optimization methods mainly achieve the purpose by changing the shape of the impeller, the stirring rate, the shape of the reactor and the time-space combination between the impellers. The sawtooth dispersing disc is concerned because it has better radial local shear capacity and turbulence intensity than other impellers of the same size (Rushton impeller, anchor impeller, etc.). It also shows good mixing effect when dealing with high-concentration solid suspensions and insoluble substances, but it also has problems such as single flow direction of the generated flow field and easy deposition at the bottom. At the same time, the introduction of axial impellers has become an important direction to solve the mixing problem of high viscosity systems. However, due to the uneven mixing of high viscosity materials at different positions, and the need to consider power consumption and other problems in actual application, the optimization of the agitated reactor of high viscosity material is still a difficult problem.

[0004] Therefore, there is an urgent need for an optimization design method for high viscosity fluid and adhesive synthesis reactor, which can comprehensively consider the unit volume power consumption of the stirring device and the mixing time under different impeller rotation speeds, and provide a reference for the optimization of high viscosity material agitated reactor. SUMMARY

[0005] The purpose of the present application is to provide a multi-shaft differential stirring structure optimization method applied to adhesive production, which effectively improves the mixing degree of high viscosity material system through the mutual combination method of differential rotation of different impellers, while maintaining low power consumption, and is suitable for high viscosity fluids of different fillers.

[0006] To achieve the above purpose, the present application provides a multi-shaft differential stirring structure optimization method applied to adhesive production, comprising: Multi-shaft differential stirred tank, which is composed of eccentric toothed dispersion shaft and axial single-paddle shaft, wherein the impeller of the eccentric toothed dispersion shaft and the axial single-paddle shaft respectively adopts toothed disc type impeller and axial flow single-blade paddle impeller; The multi-shaft differential stirred tank is applied to high viscosity fluid with different filling ratios, the eccentric toothed dispersion shaft is used as the main shaft, the axial single-paddle shaft is used as the auxiliary shaft, and the rotation speed ratio of the main shaft to the auxiliary shaft is set to be between 1 and 3.

[0007] Preferably, the position of the eccentric toothed dispersion shaft and the axial single-paddle shaft is determined according to the speed distribution, flow trajectory, mixing time and unit volume power consumption.

[0008] Preferably, the axial single-paddle shaft is located at the far end of the eccentric toothed dispersion shaft, and a single axial single-paddle shaft is selected to strengthen the mixing effect and maintain low unit volume power consumption.

[0009] Preferably, when the multi-shaft differential stirred tank is applied to high viscosity fluid, the eccentric toothed dispersion shaft with high rotation speed and the axial single-paddle shaft with low rotation speed are adopted.

[0010] Preferably, when the filling ratio of the high viscosity fluid is less than 30%, the rotation speed ratio is selected to be less than 1. When the filling ratio of the high viscosity fluid is more than 30%, the rotation speed ratio is selected to be more than 1. Therefore, the multi-shaft differential stirring structure optimization method applied to adhesive production has the following technical effects: The eccentric impeller and the differential axial single-paddle shaft are introduced, which significantly breaks the symmetrical flow field, reduces the chaos isolation area, enhances the axial flow of the material and the overall chaotic mixing, thereby effectively shortening the mixing time; meanwhile, considering the mixing time and power consumption, the stirring device with a single differential axial single-paddle shaft is adopted, which has energy saving advantage while ensuring the mixing efficiency.

[0011] The technical solutions of the present application will be further described in detail below with the aid of the drawings and examples. DESCRIPTION OF DRAWINGS

[0012] Figure 1 It is a schematic diagram of different stirring reactors in the multi-shaft differential stirring structure optimization method applied to adhesive production, wherein (a) is a single sawtooth shaft stirred tank, (b) is an eccentric single sawtooth shaft stirred tank, (c) is a single axial single-blade paddle-single sawtooth double-shaft stirred tank, (d) is a double axial single-blade paddle-single sawtooth three-shaft stirred tank, (e) is a toothed disc type impeller, and (f) is an axial flow single-blade paddle impeller. Figure 2is an injection point and observation point of a liquid tracer in a stirring reactor in an embodiment of a multi-shaft differential stirring structure optimization method applied to adhesive production, wherein (a) is a single-sawtooth-shaft stirring tank, (b) is an eccentric single-sawtooth-shaft stirring tank, (c) is a single-shaft single-blade-paddle-single-sawtooth double-shaft stirring tank, and (d) is a double-shaft single-blade-paddle-single-sawtooth triple-shaft stirring tank; Figure 3 is a three-dimensional streamline diagram of different stirring reactors in an embodiment of a multi-shaft differential stirring structure optimization method applied to adhesive production, wherein (a) is a single-sawtooth-shaft stirring tank, (b) is an eccentric single-sawtooth-shaft stirring tank, (c) is a single-shaft single-blade-paddle-single-sawtooth double-shaft stirring tank, and (d) is a double-shaft single-blade-paddle-single-sawtooth triple-shaft stirring tank; Figure 4 is a YZ velocity vector of different stirring reactors in an embodiment of a multi-shaft differential stirring structure optimization method applied to adhesive production, wherein (a) is a single-sawtooth-shaft stirring tank, (b) is an eccentric single-sawtooth-shaft stirring tank, (c) is a single-shaft single-blade-paddle-single-sawtooth double-shaft stirring tank, and (d) is a double-shaft single-blade-paddle-single-sawtooth triple-shaft stirring tank; Figure 5 is a speed distribution grouping and value position in an embodiment of a multi-shaft differential stirring structure optimization method applied to adhesive production, wherein (a) is a single-shaft group, and (b) is a multi-shaft group; Figure 6 is a normalized concentration of a liquid tracer over time and a mixing time of different stirring reactors in an embodiment of a multi-shaft differential stirring structure optimization method applied to adhesive production, wherein (a) is a normalized concentration of a liquid tracer over time of SSDM, (b) is a normalized concentration of a liquid tracer over time of ESSDM, (c) is a normalized concentration of a liquid tracer over time of ESDM-SAS, (d) is a normalized concentration of a liquid tracer over time of ESDM-DSAS, and (e) is a change of mixing time with rotational speed; Figure 7 is a unit volume power consumption and corresponding mixing time of each stirring reactor at different stirring speeds in an embodiment of a multi-shaft differential stirring structure optimization method applied to adhesive production, wherein (a) is a unit volume power consumption P v at different stirring speeds N, and (b) is a change of mixing time t with unit volume power consumption P v ; Figure 8 is a filler dispersion mixing situation of different filler ratios when the rotational speed ratio is 3:1 in an embodiment of a multi-shaft differential stirring structure optimization method applied to adhesive production, wherein (a) is a 10% filler ratio, (b) is a 20% filler ratio, (c) is a 30% filler ratio, and (d) is a 40% filler ratio; Figure 9It is a kind of filling material dispersion mixing situation of different filling material ratio in the embodiment of the multi-shaft differential stirring structure optimization method applied to adhesive production when the speed ratio is 2:1, wherein (a) is 10% filling material ratio, (b) is 20% filling material ratio, (c) is 30% filling material ratio, and (d) is 40% filling material ratio; Figure 10 It is a kind of filling material dispersion mixing situation of different filling material ratio in the embodiment of the multi-shaft differential stirring structure optimization method applied to adhesive production when the speed ratio is 1:1, wherein (a) is 10% filling material ratio, (b) is 20% filling material ratio, (c) is 30% filling material ratio, and (d) is 40% filling material ratio; Figure 11 It is a kind of mixing time of different filling material ratio under different speed ratio in the embodiment of the multi-shaft differential stirring structure optimization method applied to adhesive production. DETAILED DESCRIPTION

[0013] The application can be explained in more detail by the following examples, and the purpose of the disclosure is to protect all changes and improvements within the scope of the application, and the application is not limited to the following examples.

[0014] Example 1 The application provides a kind of multi-shaft differential stirring structure optimization method applied to adhesive production, including stirring tank impeller adopts axial flow single-blade propeller and toothed disc impeller, specific size as shown in Figure 1 And table 1.

[0015] In this embodiment, by the method of numerical simulation, different spatial combinations of axial flow single-blade propeller and toothed disc impeller are set to form four kinds of stirring reactors, i.e., single-sawtooth shaft stirring tank, eccentric single-sawtooth shaft stirring tank, single-shaft single-blade propeller-single-sawtooth double-shaft stirring tank and double-shaft single-blade propeller-single-sawtooth triple-shaft stirring tank, and they are applied to stirring flow field analysis of high-viscosity material-epoxy resin. In the numerical simulation process, in order to reduce the influence of flow dead zone of upper and lower bottom angle, the upper and lower tank walls of the stirring tank are processed with 30mm ellipse.

[0016] Table 1 Specific size of stirring tank and impeller ;

[0017] The flow process of fluid material inside the stirrer is controlled by the law of conservation of mass, the law of conservation of momentum and the law of conservation of energy, and the basic control equation group is as follows: Mass conservation equation: ; Momentum conservation equation: ; ; ; Energy conservation equation: ; where, is the velocity vector, , and are the tangential, radial and axial velocity components, , are the gravitational volume force and external volume force in the (x, y, z) directions, , or are the mass and energy source terms, and are the density , is the static pressure (Pa), is the dynamic viscosity , is the temperature, is the time, is the thermal conductivity, is the specific heat capacity.

[0018] In the simulation process of the present embodiment, the medium material is set to epoxy resin, and the material parameters are shown in Table 2.

[0019] Table 2 Material parameters ;

[0020] The unit volume power consumption is mainly obtained in the simulation experiment. After the simulation system is stable, the torque value M is obtained, and then the power consumption is calculated by the following formula, that is, the power consumption is obtained: ; ; In the formula, is the power consumption of the i-th impeller; is the volume of the stirred tank, in m 3 ; is the torque value corresponding to the impeller, in N·m; is the corresponding impeller speed, in r / s.

[0021] Mixing time is an important indicator in the production of adhesives industry, because it reflects the time required to complete the mixing process. Figure 3 ​​​The feed point (P0) and six monitoring points (P1-P6) of the liquid tracer are shown. Numerical simulation is used to track the dispersion of the tracer to estimate the mixing time, which is determined according to the 95% rule.

[0022] To investigate the flow behavior of high-viscosity adhesives within a reactor under different stirring modes, the Multi-Reference Frame (MRF) method was employed, treating the region containing the blades as the rotating dynamic domain and other regions as the static domain. In this embodiment, the stirring tank wall was designated as the static wall, while the stirring shaft and its impeller were designated as the moving wall. Ansys Fluent 2022 R1 was used for steady-state calculations, with a single-phase simulation system, providing assistance for optimizing the structure of the stirred reactor during epoxy resin adhesive mixing. The pressure-velocity coupled solution method, SIMPLE, was used, with the impeller speed set to 300 rpm and the stirring direction counterclockwise. The convergence residual was set to 10. -5 .

[0023] In the numerical simulation, the origin of the coordinate system was set at the top of the centerline of the stirring shaft, with upwards being positive. To ensure the accuracy of the simulation, the impeller and shaft regions underwent mesh refinement. Due to the presence of many sharp areas in the geometric model, an unstructured hybrid mesh type was used for mesh generation. Mesh independence verification showed that the number of meshes had a negligible impact on the velocity distribution in the simulation system. Therefore, to save computational resources, the mesh size was selected as follows: 906949 for the single-tooth shaft stirred tank, 908350 for the eccentric single-tooth shaft stirred tank, 1157507 for the uniaxial single-blade impeller-single-tooth dual-shaft stirred tank, and 1399496 for the biaxial single-blade impeller-single-tooth triaxial stirred tank.

[0024] Based on this, this embodiment utilizes CFD computational fluid dynamics to investigate the influence of different stirred reactors on the mixing performance of high-viscosity materials, as detailed below: (1) Fluid trajectory: At 300 r / min on the serrated disc shaft -1 Axial single impeller shaft 100 r·min -1 At different rotational speeds, the flow trajectories inside the four types of stirred reactors are as follows: Figure 3 As shown. Figure 3 Image (a) shows the overall fluid trajectory of the serrated disc agitator under high-viscosity material conditions. It can be observed that it mainly consists of regional stratification of the isolation zone and an ordered, symmetrical axial trajectory. The upper part of the trajectory is affected by the accumulation of high-viscosity material due to the climbing of the shaft and impeller rotation. After changing the impeller position (…), Figure 3 In (b), the symmetrical trajectory is deflected. Some materials are squeezed towards a certain area by the combined action of gravity and the rotational force of the agitator, resulting in a slight axial flow trajectory. However, this also exposes the problem of a large non-eccentric end isolation zone and insufficient flow. Figure 3Figure (b) shows the three-dimensional fluid trajectory distribution after the introduction of the axial single-blade impeller. It can be observed that the introduction of the axial single-blade impeller significantly improves the anisotropic flow of the fluid within the stirred tank. Furthermore, the fluid is not only mixed axially by the collision between the serrated disc impeller and the tank wall, but also by the rotation of the axial single-blade impeller in the upper and lower regions, effectively reducing the problem of insufficient flow in the mixing isolation zone and at the non-eccentric ends. The internal three-dimensional fluid trajectory distribution of the dual single-blade axial flow-serrated disc triaxial mixing and stirring device is as follows: Figure 3 As shown in (d), it can be seen that compared to Figure 3 In the middle (c), the mixing flow in the upper and lower regions is more concentrated. The axial streamlines that should appear around the serrated disc impeller are also changed by the rotation of the two axial single-blade shafts. The coverage of the fluid flow trajectory in the stirred tank is also higher, indicating that the mixing performance of this stirring device is better without considering power consumption.

[0025] (2) Velocity distribution: At 300 r / min on the serrated disc shaft -1 Axial single impeller shaft 100 r·min -1 At different rotational speeds, the velocity distribution and internal flow trajectories of the four stirred reactors are as follows: Figure 4 As shown. Based on the distance from the serrated disc impeller, this embodiment divides the mixing vessel into two regions—the near-serrated impeller region (A) and the far-serrated impeller region (B). Figure 4 As shown in (a), the single-serrated disk turbine stirred tank generates a symmetrical stirring cycle for the high-viscosity fluid. Typical symmetrical saddle vortices, characteristic of high-viscosity laminar flow, appear in region B, indicating that this region is largely within the mixing isolation zone. Similarly, symmetrical annular vortices appear in region A, which would hinder overall mixing within the stirred tank. The YZ velocity distribution cross-section of the eccentric serrated disk turbine stirred tank is shown in Figure [Figure number missing]. Figure 4 As shown in (b), changing the position of the stirring shaft and impeller from the center to the eccentric breaks its symmetrical flow field structure, almost eliminates the annular vortex in region A, and greatly compresses the isolation zone near the impeller end in region B. However, this also makes the isolation zone at the distal end larger and more difficult to mix.

[0026] To address this isolation zone issue, this embodiment introduces a low-speed axial single-propeller shaft at the distal end of the eccentric shaft, such as... Figure 4 As shown in (c), the flow field after adding the axial single propeller shaft exhibits a significant amount of disordered flow. This drastically reduces the isolation regions in A and B, breaking down the originally large isolation areas into smaller vortices and increasing the overall chaotic mixing in the flow field. However, after introducing two axial single propeller shafts, as shown in [the diagram]... Figure 4 As can be seen in (d), the degree of disorder in the flow field is higher and there are more small eddies. Therefore, it is preliminarily judged that the mixing effect of the material in the flow field is better.

[0027] The above results verify that the introduction of the axial single-blade shaft can effectively increase the axial flow of high-viscosity fluid, thereby effectively improving the mixing of the upper and lower regions and the mixing isolation zone problem of the single-sawtooth disc shaft. At the same time, under the coupling action of the axial single-blade impeller and the sawtooth disc impeller, the randomness of fluid flow is increased, the disordered flow of high-viscosity fluid in the stirred tank is strengthened, and the mixing effect is improved.

[0028] To further reveal the regulation mechanism of the spatial position and structure of different stirring impellers on the flow field distribution and mixing degree in the stirred tank, four different stirred tanks are divided into two groups in this embodiment: the first group is a single-shaft group, including a single-sawtooth dispersion stirred tank (SSDM) and an eccentric-sawtooth dispersion stirred tank (ESSDM), which takes the velocity in three axial directions at a distance of 0.5D, 1D and 1.5D from the impeller as the analysis object, where D is the diameter of the stirred tank. is the distance from the center of the stirring shaft to the value position; the second group is a multi-shaft group, including a single-shaft single-blade-paddle-single-sawtooth double-shaft stirred tank (ESDM-SAS) and a double-shaft single-blade-paddle-single-sawtooth three-shaft stirred tank (ESDM-DSAS), which takes the velocity in three axial directions at a distance of 0.5D, 1D and 1.5D from the stirred tank as the analysis object, is the distance from the center of the stirred tank to the value position, as shown in Figure 5 .

[0029] By analyzing the velocity distribution at different spatial positions, it is found that in the single-shaft group stirred tank, the axial, radial and tangential velocity distributions at the positions of 0.5D and 1D are relatively small, while the axial velocity distribution at the position of 1.5D is relatively large, the axial velocity distribution of SSDM is close to 0, and ESSDM has a fluctuation in the velocity distribution. This is because the position of 1.5D is close to the wall in SSDM, and most of the kinetic energy generated by the impeller is absorbed by the material and the wall in the process of reaching this position; while the position of 1.5D is at the center position of the non-eccentric end in ESSDM. This further proves that the dispersion effect of the eccentrically placed impeller on the high-viscosity flow field is better than that of the centrally placed impeller. At the same time, both SSDM and ESSDM have peaks in the axial and tangential velocities, while the radial velocity changes relatively gently, which shows that the sawtooth dispersion disc has a good effect on the axial and tangential directions in the high-viscosity flow field.

[0030] ​​​​​​​​​​​Compared with single shaft, the introduction of differential shaft has greater influence on the velocity distribution of the upper end of the flow field, and the velocity distribution at the same position has multiple peaks, which shows that the introduction of differential shaft flow shaft has certain regulation effect on the velocity distribution of the overall flow field. However, the velocity distribution of the flow field in the non-eccentric end of the ESDM-DSAS is more gentle than that of the ESDM-SAS, which is because the two differential shaft flow shafts in the asymmetric model of the ESDM-DSAS almost block the fluctuation of the high-speed toothed dispersion disc.

[0031] The mixing performance of different groups of stirred tanks is further analyzed by the isosurface and vorticity in this embodiment. The isosurfaces of the velocity of 0.01 m / s, 0.05 m / s, 0.1 m / s and 0.2 m / s are selected to analyze the effects of different stirring reactors, and it is found that when the velocity isosurface is equal to 0.01 m / s, there is still a large area of blank in the upper end of the SSDM and the ESSDM, which shows that whether the eccentricity is placed or placed in the center, the single sawtooth disc impeller cannot fully consider the mixing of the upper and lower halves. The upper and lower halves of the ESDM-SAS and ESDM-DSAS stirred tanks are mostly in the isosurface.

[0032] At the velocity isosurfaces of 0.1 m / s and 0.2 m / s, the velocity isosurface distribution of all stirring devices is mainly concentrated in the impeller / blade area, and the stirring impellers of the multi-shaft system hardly affect each other at a higher velocity isosurface. This phenomenon is caused by the fact that the material viscosity in the stirred tank is large, which seriously hinders the kinetic energy transmission of the impeller rotation. Therefore, in order to strengthen the mixing of high-viscosity materials in the stirring device and convert regional mixing into global mixing, it is necessary to introduce differential axial single-paddle shafts.

[0033] In addition, by analyzing the isosurface distribution of different vortices of different stirring reactors at the same stirring speed, it is found that under the condition of low vorticity (t) ), the eccentric placement of the main impeller indeed causes changes in the vortex structure, but the changes are small; after the introduction of the differential axial single-paddle shaft, the flow field inside the stirred tank changes significantly, and the vortex structure around the main impeller is also affected by the differential shaft and changes jointly. However, as the vorticity value increases, the influence of the eccentric main shaft and the differential shaft on the vortex structure around the main shaft becomes smaller and smaller, and when , the vorticity isosurface around the sawtooth disc impeller basically does not change, which is due to the fact that the large material viscosity hinders the kinetic energy transmission, and the stirring shafts in the same device are far apart and cannot form a joint effect, which is consistent with the analysis results of the velocity isosurface above.

[0034] (3) Mixing time: Figure 6The dimensionless concentration of liquid tracer in different stirred reactors at 300r / min-100r / min is shown in the following figure. In each stirring device, the dimensionless concentration curve gradually converges to a stable value over time.

[0035] The mixing time of high viscosity material in different stirred reactors is 141.87s, 135.32s, 122.81s and 117.04s respectively. It can be found that under the same conditions, the placement of eccentric impeller shortens the mixing time by 4.62%, and the introduction of differential speed axial single paddle shaft (ESDM-SAS and ESDM-DSAS) shortens the mixing time by 13.43% and 17.5% respectively. These show that the eccentric placement of impeller and the introduction of differential speed axial single paddle shaft have a positive effect on the mixing of materials in stirred tank, and the latter has a greater reduction in mixing time, proving that it has stronger mixing ability for high viscosity materials.

[0036] It can be found from the figure that with the increase of speed, the mixing time of SSDM and ESSDM devices is greatly reduced, while ESDM-SAS and ESDM-DSAS devices maintain a slow reduction trend. Generally speaking, under the same sawtooth shaft speed, the mixing time of SSDM and ESSDM devices is higher than that of ESDM-SAS and ESDM-DSAS. At the same time, the mixing time of ESDM-SAS and ESDM-DSAS devices under the same speed is close, which shows that under certain conditions, the introduction of single axial single paddle shaft has met the mixing requirements.

[0037] In order to further analyze and verify, the unit volume power of different stirred reactors is also compared, as shown in Figure 7 It can be seen from Figure 7 that ESDM-SAS and ESDM-DSAS devices have differential speed axial single paddle shaft, and their unit volume power consumption is much higher than that of SSDM and ESSDM under the same sawtooth shaft speed. In summary, the introduction of differential speed axial single paddle shaft not only effectively strengthens the mixing effect of high viscosity materials in stirred reactors, but also greatly increases the unit volume energy consumption.

[0038] Figure 7The mixed time and unit volume power consumption are plotted in the graph, and the smaller Y coordinate indicates shorter mixed time, and the smaller X coordinate indicates smaller power consumption, so the image is closer to the origin (i.e. Lower power consumption), and the device can obtain lower mixing time at lower power consumption, that is, better mixing effect. It can be seen that, compared with the other three stirring devices, the ESDM-SAS has smaller unit volume stirring power and smaller mixing time, which confirms that the single shaft is sufficient to strengthen the stirring and mixing of high-viscosity fluid materials after the introduction of the differential shaft single-paddle shaft, and the strengthening range of the double differential shaft single-paddle shaft is not large, and the power consumption is also larger, which does not meet the requirement of "reducing power consumption while ensuring smaller mixing time". Therefore, when facing the mixing and stirring of high-viscosity materials, it is a good choice to introduce a differential shaft single-paddle shaft for stirring reinforcement, and the mixing efficiency and mixing performance of the mixing device with an introduced single-paddle shaft are greater than those of the mixing device with multiple introduced single-paddle shafts.

[0039] Example Two Since the addition of inorganic fillers can improve the mechanical properties, aging resistance and corrosion resistance of adhesives, it is common to add different types and proportions of particulate fillers during the preparation of adhesives.

[0040] Based on this, the present application verifies the dispersion effect of different fillers by designing different speed ratios between the main shaft (tooth-shaped dispersion shaft) and the auxiliary shaft (axial single-paddle shaft) and combining different fillers or different filler proportions.

[0041] When the speed ratio is 3:1 (main shaft: auxiliary shaft), the filler dispersion and mixing conditions of fillers with proportions of 10%, 20%, 30% and 40% are as shown in the following table: Figure 8 It can be seen that as the proportion of fillers increases, the mixing time becomes less, but when the filler ratio reaches more than 30%, the mixing time changes to a stable trend.

[0042] When the speed ratio is 2:1 (main shaft: auxiliary shaft), the filler dispersion and mixing conditions of fillers with proportions of 10%, 20%, 30% and 40% are as shown in the following table: Figure 9 Under this speed ratio, as the proportion of fillers increases, the mixing time becomes less and the mixing effect becomes better.

[0043] When the speed ratio is 1:1 (main shaft: auxiliary shaft), the filler dispersion and mixing conditions of fillers with proportions of 10%, 20%, 30% and 40% are as shown in the following table: Figure 10 Figure 10 ​The middle (a) shows that when the filler is 10%, the dimensionless concentration does not reach 95% at the stable time, so it can be judged that under the condition of the speed ratio, it is difficult to mix the 10% filler uniformly. When the filler ratio is 20%, the mixing time is shorter, and when it is 30% and 40%, the mixing time is much higher than the speed ratio of 3:1 and 2:1, which means that in the case of high filler ratio, the stirring device with high speed ratio difference can quickly stir the filler in the high viscosity material uniformly.

[0044] In this embodiment, the mixing time is used to quantify the mixing effect, and the mixing effect of different filler ratios under different speed ratios is comprehensively evaluated, as shown in Figure 11 It can be seen that the mixing of high filler ratio under high speed ratio is more stable, so the speed ratio of 3:1 (main shaft: auxiliary shaft) is preferred for high filler ratio materials.

[0045] Therefore, the application of the above-mentioned multi-shaft differential stirring structure optimization method for adhesive production can significantly break the symmetrical flow field, reduce the chaos isolation zone, enhance the axial flow of the material and the overall chaotic mixing, thereby effectively shortening the mixing time.

[0046] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application but not to limit it, although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that: it can still modify or equivalently replace the technical solutions of the present application, and these modifications or equivalent replacements also cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A method for optimizing a multi-shaft differential stirring structure applied to adhesive production, characterized by, The multi-shaft differential stirred tank is composed of an eccentric toothed dispersion shaft and an axial single-paddle shaft, wherein the impeller of the eccentric toothed dispersion shaft and the axial single-paddle shaft is respectively a toothed disc type impeller and an axial flow single-blade paddle impeller. The multi-shaft differential stirred tank is applied to high viscosity fluid with different filler ratios, the eccentric toothed dispersion shaft is used as a main shaft, the axial single-paddle shaft is used as an auxiliary shaft, and the rotation speed ratio of the main shaft to the auxiliary shaft is set to be between 1 and 3.

2. The method for optimizing the multi-shaft differential stirring structure applied to the adhesive production according to claim 1, characterized in that, The position of the eccentric toothed dispersion shaft and the axial single-paddle shaft is determined according to the speed distribution, flow trajectory, mixing time and unit volume power consumption.

3. The method for optimizing the multi-shaft differential stirring structure applied to the adhesive production according to claim 2, characterized in that, The axial single-paddle shaft is located at the far end of the eccentric toothed dispersion shaft, and a single axial single-paddle shaft is selected to strengthen the mixing effect and maintain low unit volume power consumption.

4. The method for optimizing the multi-shaft differential stirring structure applied to the adhesive production according to claim 1, characterized in that, When the multi-shaft differential stirred tank is applied to high viscosity fluid, the eccentric toothed dispersion shaft with high rotation speed and the axial single-paddle shaft with low rotation speed are adopted.

5. The method for optimizing the multi-shaft differential stirring structure applied to the adhesive production according to claim 1, characterized in that, In the filler ratio 30% of the high viscosity fluid, select high speed ratio for material mixing, set the spindle: auxiliary shaft = 3:1.

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