CN113386292A - Casting roller and three-factor parameter orthogonal experimental method - Google Patents

Abstract

The invention discloses a casting roller and a three-factor parameter orthogonal experimental method, wherein the casting roller comprises an outer roller, an inner roller, a central shaft, an end cover, a cooling water runner and a guide plate; an inner roller is arranged in the outer roller, at least two guide plates are arranged between the outer roller and the inner roller, a cooling water flow channel is formed between the adjacent guide plates, a central shaft is arranged on the central axis of the inner roller, and end covers are arranged at two ends of the casting roller body. According to the invention, SolidWorks software modeling, ANSYS Fluent software simulation and Design-Export software data analysis are used, the influence of three factors, namely the outer diameter of an outer roller, the flow channel lead and the flow channel size, on the cooling effect is analyzed, the cooling efficiency is reflected by the mean value of the outlet temperature of the casting film through three-factor orthogonal test analysis, the surface temperature uniformity of the film is reflected by the temperature range difference value of the casting film after cooling, and a group of optimal structural parameters capable of improving the cooling efficiency of the casting film on the casting roller and the temperature uniformity of the film is obtained.

Description

Casting roller and three-factor parameter orthogonal experimental method

Technical Field

The invention relates to the field of casting roller structures of lithium battery diaphragm production lines, in particular to a casting roller and a three-factor parameter orthogonal experimental method.

Background

The tape casting method is a long-history forming technology, and is widely applied to the fields of plastics, paper making, paint and the like, the cooling forming process of the tape casting method mainly occurs on a tape casting roller, the tape casting roller is also called as a cooling roller, the diameter of the tape casting roller is larger, the tape casting roller is made of steel, the surface of the tape casting roller is passivated by plating hard chromium, an inner sleeve is arranged in a hollow mode, a straight or spiral guide vane is welded on the inner sleeve, a flow channel is formed in the space among the steel roller, the inner sleeve and the guide vane, and cooling water flows in the flow channel in a circulating mode. The quality and yield of the cast film are greatly affected directly by the cooling effect of the casting roll. At present, in the existing casting roller structure, the number of runners is small, the direct conduction area of a membrane and cooling water is small, the cooling efficiency is low, and the uniformity of the surface temperature of the membrane is poor. Therefore, in the cooling process, the low cooling efficiency and the unevenness of the surface temperature of the casting film are two main causes that the quality of the casting film cannot be improved.

Disclosure of Invention

The invention provides a casting roller and a three-factor parameter orthogonal experimental method, which are used for solving the problems of low cooling efficiency of the casting roller on a casting film and low and uneven surface temperature of the casting film.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a casting roller comprises an outer roller, an inner roller, a central shaft, an end cover, a cooling water flow passage and a guide plate; the inner roller is arranged in the outer roller, at least two guide plates are arranged between the outer roller and the inner roller, the cooling water flow channel is formed between the adjacent guide plates, the central shaft is arranged on the central axis of the inner roller, and the end covers are arranged at two ends of the casting roller body.

Further, the cooling water flow channel is provided with a water inlet and a water outlet; the water inlet and the water outlet are arranged at the same end of the cooling water flow channel.

Further, the water flow directions in the two adjacent cooling water flow channels are opposite.

Furthermore, the water flow directions in the same cooling water flow channel are the same.

A three-factor parameter orthogonal experimental method based on a casting roller structure comprises the following steps:

the first step is as follows: establishing a physical model of a casting roller and a casting film in three-dimensional modeling software Solidworks, respectively carrying out grid division on the casting film, the casting roller and a cooling water module by using Imem grid division, setting the contact surface of the surface of an outer roller and the air as a convection heat exchange model, setting the contact surfaces of the side surface and the top surface of the casting film and the air as a convection heat exchange model, and setting a coupling surface between the casting film and the casting roller;

the second step is that: according to the physical model established in the first step, the influence of three factor parameters, namely the outer diameter of the outer roller, the size of the runner and the lead of the runner, on the cooling efficiency of the casting roller and the surface temperature of the casting film is respectively researched, and when one factor parameter value is changed in simulation, the other two factor parameter values are kept unchanged;

the third step: according to the optimal selection result of the single factor in the second step, the influence of three factor parameters of the outer roller outer diameter, the size of the runner and the runner lead on the cooling efficiency of the casting roller and the surface temperature of the casting film is analyzed and researched by adopting an orthogonal test;

the fourth step: and solving the regression model according to the quadratic polynomial regression model of the temperature mean value and the temperature range value obtained in the third step to obtain the optimal structure parameters of the casting roller.

Further, the optimal structural parameters are that the outer diameter of the outer roller is 680mm, the size w multiplied by h of the flow channel is 38 multiplied by 30mm, and the lead of the flow channel is 634 mm.

The casting roller structure designed by the invention increases the heat exchange area between the casting film and the cooling water, so that the temperature on the surface of the casting film can exchange heat uniformly, and the influence of three factor parameters, namely the outer diameter of the roller, the size of the runner and the lead of the runner, on the temperature on the surface of the casting film is researched and analyzed by establishing three-dimensional software, so that the heat exchange area between the casting roller structure and the casting film is increased, and the temperature on the surface of the casting film is uniform.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a view showing a structure of a casting roll;

FIG. 2 is a schematic view of the internal water inlet and outlet channels of the casting roll;

FIG. 3 is an assembly view of a casting roller and a casting film;

FIG. 4 is a sectional view of a structure of a casting roll;

FIG. 5 is a graph of mean cast film exit temperature as a function of casting roll diameter;

FIG. 6 is a graph of temperature variation with casting roll diameter after cooling of a cast film;

FIG. 7 is a graph of mean cast film exit temperature as a function of lead;

FIG. 8 is a graph of temperature variation with lead after cooling of a cast film;

FIG. 9 is a graph showing the variation of the mean value of the exit temperature of the casting film with the width of the bead while maintaining the sectional area of the bead constant;

FIG. 10 is a graph showing a temperature variation value according to a width of a bead after a cast film is cooled, with a cross-sectional area of the bead being maintained constant;

FIG. 11 is a second view of the structure of the casting roll;

FIG. 12 is a third drawing of the structure of the casting roll;

FIG. 13 is a fourth drawing of the structure of the casting roll;

FIG. 14 is a fifth diagram of the structure of the casting roller.

In the figure, 11, a central shaft, 12, an outer roller, 13, an inner roller, 14, an end cover, 15, a cooling water runner 16, a guide plate, 17, a casting roller, 18 and a casting film.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1 to 4 and fig. 11 to 14, the casting roll comprises an outer roll 12, an inner roll 13, a central shaft 11, an end cover 14, a cooling water runner 15 and a deflector 16; the inner roller 13 is arranged in the outer roller 12, at least two guide plates 16 are arranged between the outer roller 12 and the inner roller 13, the cooling water flow channel 15 is formed between the adjacent guide plates 16, the central shaft 11 is arranged on the central axis of the inner roller 13, and the end covers 14 are arranged at two ends of the casting roller body. In this embodiment, it is preferable that the central shaft 11 is made of white steel, which can support the roller body and introduce and guide cooling water; the end covers 14 are made of white steel, so that the cooling water flow channels 15 are sealed at two ends of the roller body, leakage is prevented, and the inner roller body and the outer roller body can be supported; the section of the cooling water flow channel 15 is rectangular, 10 cooling water flow channels 15 are formed in the roller body by 10 guide plates 16, cooling water enters the central shaft 11 and is divided into two parts by a flow dividing throttle valve, then the two parts are connected with a pipeline through a rotary joint and respectively led to each cooling water flow channel 15 through the pipeline, cooling water at a water outlet is led to the central shaft 11 after passing through the pipeline, the pipeline is connected with the central shaft 11 through the rotary joint and then flows out of the central shaft 11; the specific cross-convection condition of the cooling water is shown in fig. 2, wherein 1-10 in fig. 2 are numbered on one side of the cooling water flow channel, 1 '-10' are numbered on the other side of the cooling water flow channel, wherein the same numbers are the same cooling water flow channel, and the arrow direction is the flow direction of the water flow, which indicates the water inlet and outlet conditions of each flow channel;

further, the cooling water flow passage 15 is provided with a water inlet and a water outlet; the water inlet and the water outlet are arranged at the same end of the cooling water flow passage 15.

Further, the water flow directions in the two adjacent cooling water flow passages 15 are opposite.

Further, the water flow directions in the same cooling water flow passage 15 are the same.

In addition, the three-factor parameter orthogonal experimental method based on the casting roller structure comprises the following steps:

the first step is as follows: establishing a physical model of a casting roller and a casting film in three-dimensional modeling software Solidworks, respectively carrying out grid division on the casting film, the casting roller and a cooling water module by using Imem grid division, setting the contact surface of the surface of an outer roller and the air as a convection heat exchange model, setting the contact surfaces of the side surface and the top surface of the casting film and the air as a convection heat exchange model, and setting a coupling surface between the casting film and the casting roller; in this example, modeling of the casting roll and the casting film was done using the three-dimensional modeling software Solidworks, as shown in fig. 3 for an assembly of the casting roll and the casting film. And carrying out meshing by using the Imem, wherein in order to ensure that the divided meshes have higher quality and ensure the speed and the precision of numerical calculation, the assembling body model is divided into a plurality of regular sub-blocks when the meshes are divided, and the three modules of the casting film, the casting roller and the cooling water are respectively subjected to meshing. The diaphragm is divided into six layers by adopting hexahedral meshes, and the film is divided into six layers by using a sweeping method. The casting roller module adopts a mixed mode of a tetrahedron and a hexahedron to carry out meshing, the cooling water module adopts a mode of sweeping meshes to carry out meshing, and an expansion layer is added to the cooling water module. The division is that the number of grid nodes is 13916634, the number of cells is 3182737, the average torsion resistance is 0.209, the grid quality is good, and different grid division nodes, the number of cells, the average torsion resistance and the like are set according to the experimental condition according to the division of different grids of the simulation requirement.

The cooling water inlet adopts the boundary condition of mass inlet, the speed is 64961Kg/h, the temperature is 10 ℃, the outlet adopts the boundary condition of pressure outlet, and the outlet pressure is 1.5 Mpa. The surface linear velocity of the casting roller and the initial temperature of the membrane are 240 ℃. The contact surface of the outer roller surface and the air is set as a convection heat exchange model, and the heat exchange coefficient is 3W/(m.K); the contact surfaces of the side surface and the top surface of the casting film and air are set as a convection heat exchange model, and the heat exchange coefficient is 5W/(m.K). A coupling surface is arranged between the casting film and the casting roller.

In software, a turbulence model is set as a K-omega turbulence model, a Coupled algorithm is adopted for pressure and speed coupling, a Standard format is selected for a pressure interpolation method, and a second-order windward format is adopted for discrete formats of turbulence energy and turbulence dissipation rate.

The second step is that: according to the physical model established in the first step, the influence of three factor parameters, namely the outer diameter of the outer roller, the size of the runner and the lead of the runner, on the cooling efficiency of the casting roller and the surface temperature of the casting film is respectively researched, and when one factor parameter value is changed in simulation, the other two factor parameter values are kept unchanged; in this embodiment, in order to study the cooling effect and the surface temperature uniformity of the casting film on the casting roll, five straight lines are uniformly taken along the thickness direction at the outlet of the casting film from the surface of the casting roll, the lengths of 250mm at both ends in the width direction of the film sheet are removed during calculation in consideration of the subsequent trimming process of the casting film, 1000 points are uniformly taken at the remaining part of each straight line, the temperature values of the points are taken, and the temperature mean value and the temperature range value are obtained. The cooling efficiency of the casting film on the casting roll is reflected by the average temperature value, and the temperature uniformity of the surface of the film sheet is reflected by the extreme temperature difference value. When the influence of the outer diameter of the roller, the size of a flow passage and the lead on the cooling effect is respectively researched, a variable control method is adopted, namely when the influence of a certain factor is researched, the quantity of the factor is continuously changed, the other two factors keep the initial values of the factors unchanged, and when the factor is changed, the change of the cooling effect is researched.

The outer diameter D of the outer roller, the thickness delta of the outer roller wall, the flow channel dimension w × h (width × height) of 45 × 25mm and the flow channel lead T of 834mm, which are conventional in the factory, were set as initial values for simulation and used as a control group. In order to investigate the influence of the outer diameter D of the casting roll on the cooling effect of the casting film, the casting film and the casting roll assembly were subjected to numerical simulation under the conditions of D600, 660, 720, 780, and 840mm, respectively, and simulated using ANSYS Fluent software, in which case the lead T and the bead section dimension w × h were kept constant. The simulation results are shown in table 1. FIG. 5 is a graph of the mean value of the exit temperature of the cast film as a function of the outer diameter of the roll. Fig. 6 is a graph of temperature variation with the outer diameter of the roll after the cast film is cooled. As shown in fig. 5 and 6, the average temperature value and the temperature variation value both show a gradually decreasing trend with increasing diameter.

TABLE 1 temperature in width direction at outlet of casting films of different diameters

Diameter D/mm	600	660	720	780	840
						Temperature mean value/K	309.970	305.162	301.674	298.104	295.482
Temperature difference value/K	2.334	1.967	1.721	1.389	1.227

In order to examine the influence of the lead T of the spiral bead on the cooling effect of the casting film, the assembly of the casting film and the casting roll was subjected to numerical simulation under the conditions of T634, 734, 834, 934, 1034mm, respectively, and the outer diameter D of the outer roll and the dimension w × h of the bead section were kept unchanged at the initial values, and the simulation results are shown in table 2. FIG. 7 is a graph of mean values of casting film outlet temperatures as a function of lead. Fig. 8 is a graph of a temperature variation value with lead after cooling of the casting film. As shown in fig. 7 and 8, the mean and the range of the temperature of the diaphragm after cooling both increased with increasing lead.

TABLE 2 temperatures in the width direction at the exit of different lead cast films

Lead T/mm	634	734	834	934	1034
						Temperature mean value/K	310.021	311.537	315.082	315.236	316.943
Temperature difference value/K	1.703	1.980	2.531	2.544	2.718

In order to research the influence of the size of the runner on the cooling effect of the casting film, the flow and the flow speed of cooling water are assumed to be fixed, so that the area S of the cross section of the runner is a certain value, the cross section of the runner is rectangular, and the width w and the height h of the runner are integers for the convenience of grid division. The widths of the flow channel sections are set to be 35, 40, 45, 50 and 55mm respectively, and the heights of the corresponding flow channel sections are set to be 32, 28, 25, 22.5 and 20.5mm respectively. At this time, the outer diameter D and the lead T of the outer roller keep unchanged. The simulation results are shown in table 3. Wherein, fig. 9 is a graph of the average value of the exit temperature of the casting film varying with the size of the bead, and fig. 10 is a graph of the temperature variation value varying with the size of the bead after the casting film is cooled. As shown in fig. 9 and 10, the average value after the cooling of the casting film increases as the aspect ratio of the bead increases, the variation width gradually decreases, and the very different value decreases as the aspect ratio of the bead increases.

TABLE 3 temperature in width direction at exit of casting film of different bead sizes

The third step: according to the optimal result of the single factor of the second step, the influence of three factor parameters of the outer roller outer diameter, the size of the runner and the lead of the runner on the cooling efficiency of the casting roller and the surface temperature of the casting film is analyzed and researched by adopting an orthogonal test.

Through the second step single factor test, it can be seen that the outer roller outer diameter, the runner size and the runner lead have different trends and different degrees on the influence of the cast film cooling effect. Therefore, a multifactor orthogonal test is required for the structure of the casting roll to obtain a more accurate result. And (3) optimizing three parameters of the outer roller outer diameter, the flow channel lead and the flow channel size by using Design-Expert 8.0 software aiming at a single-factor optimal selection result. And selecting the average temperature and the temperature difference value after the cast film is cooled as optimization targets, and establishing an orthogonal test table to perform numerical simulation on the cooling effect of the cast film. The simulation experiment factors and levels are shown in table 4. The results of the simulation tests are shown in table 5.

TABLE 4 simulation experiment factors and levels

Level of	Roller external diameter D/mm	Lead T/mm	Flow channel width w/mm
				1	600	634	35
2	720	834	45
				3	840	1034	55

TABLE 5 results of orthogonal experiments

From the data samples in table 5, a quadratic polynomial regression model of the temperature mean and temperature range values was obtained.

Y₁＝404.978-0.209D-0.822w+0.028T+0.000751Dw-0.000017DT-0.000388wT+0.000090D²+0.003792w²+0.000009T²

Y₂＝4.992-0.021D+0.004w+0.014T-0.000281Dw-0.000003DT-0.000034wT+0.000021D²+0.002462w²-0.000005T²

In the formula: y is₁Is the average value of the temperature at the outlet of the casting film; y is₂Is the temperature range value at the outlet of the casting film; d is the outer diameter of the outer roller; w is the width of the flow channel; t is the lead.

Considering the crystallization problem of the casting film, aiming at a regression model, an Optimization function in Design-Export 8.0 software is applied, the temperature mean value range of the casting film is 303-313.766K, the minimum temperature range is taken as a condition, and the optimal structure parameters of the casting roller obtained by solving the regression model are that the outer diameter of an outer roller is 680mm, the size of a runner is 38 x 30mm, and the lead of the runner is 634 mm. The optimized temperature mean value is reduced by 0.23323K compared with the temperature mean value of the control group, and the temperature range difference value is improved by 13.88 percent compared with the temperature range difference value of the control group.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (6)

1. A casting roller is characterized by comprising an outer roller (12), an inner roller (13), a central shaft (11), an end cover (14), a cooling water runner (15) and a guide plate (16); the inner roller (13) is arranged in the outer roller (12), at least two guide plates (16) are arranged between the outer roller (12) and the inner roller (13), cooling water flow passages (15) are formed between adjacent guide plates (16), the central shaft (11) is arranged on the central axis of the inner roller (13), and the end covers (14) are arranged at two ends of the casting roller body.

2. Casting roll according to claim 1, characterized in that the cooling water runners (15) are provided with water inlets and outlets; the water inlet and the water outlet are arranged at the same end of the cooling water flow channel (15).

3. A casting roll according to claim 1, wherein the directions of water flow in said adjacent two cooling water flow passages (15) are opposite.

4. Casting roll according to claim 1, characterized in that the water flow direction in the same cooling water channel (15) is the same.

5. A casting roll three-factor parameter orthogonal experimental method based on any one of claims 1 to 4, characterized by comprising the following steps:

the first step is as follows: establishing a physical model of a casting roller and a casting film in three-dimensional modeling software Solidworks, using ICEM (Integrated computer electronics) grid division to respectively grid divide three modules of the casting film, the casting roller and cooling water, setting the contact surface of the surface of an outer roller and air as a convection heat exchange model, setting the contact surfaces of the side surface and the top surface of the casting film and the air as a convection heat exchange model, and setting a coupling surface between the casting film and the casting roller;

the second step is that: according to the physical model established in the first step, the influence of three factor parameters, namely the outer diameter of the outer roller, the size of the runner and the lead of the runner, on the cooling efficiency of the casting roller and the surface temperature of the casting film is respectively researched, and when one factor parameter value is changed in simulation, the other two factor parameter values are kept unchanged;

the third step: according to the optimal selection result of the single factor in the second step, the influence of three factor parameters of the outer roller outer diameter, the size of the runner and the runner lead on the cooling efficiency of the casting roller and the surface temperature of the casting film is analyzed and researched by adopting an orthogonal test;

the fourth step: and solving the regression model according to the quadratic polynomial regression model of the temperature mean value and the temperature range value obtained in the third step to obtain the optimal structure parameters of the casting roller.

6. A casting roll three-factor parameter orthogonal experimental method as claimed in claim 5, characterized in that the optimal structural parameters are outer roller outer diameter of 680mm, runner dimension w x h of 38 x 30mm, runner lead of 634 mm.

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