Nozzle structure optimization method, system and device for high-solid-phase slurry extrusion

Abstract

The invention discloses a nozzle structure optimization method, system and device for high-solid-phase slurry extrusion, and relates to the technical field of nozzle structure optimizing.The method comprises the steps that rheological property parameters of high-solid-phase slurry to be extruded are obtained; the method comprises the following steps: selecting a rheological constitutive of high-solid-phase slurry, and constructing a rheological model; an initial nozzle structure model is established for simulation analysis, and simulation process boundary parameters are determined; the simulation process boundary parameters are input into the rheological model to obtain the pressure, the velocity field and the particle distribution field of the initial extrusion process; nozzle structure characteristic parameters are selected as control variables, the minimum pressure drop of the extrusion input end and the extrusion output end is obtained as an optimization criterion, nozzle structure parameter variables are optimized, and a parameter optimization set is obtained; nozzle structure parameters under the condition that the pressure drop is minimum are selected, and optimization of the nozzle structure is completed; by means of the method, the problems that solid-liquid separation and nozzle blocking are prone to occurring during extrusion type 3D printing of the high-solid-phase slurry can be effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of nozzle structure design, and in particular to a nozzle structure optimization method, system and device for high solid phase slurry extrusion. Background Art

[0002] 3D printing is a technology that uses a layer-by-layer accumulation method to manufacture solid parts. It does not require traditional processing tools such as cutting tools and molds or multiple processing steps. Advanced printing equipment can use CAD design data to quickly and accurately manufacture parts of any complex shape. Extrusion 3D printing is a technology that extrudes printable materials through a nozzle under the action of mechanical force, and then selectively deposits to build solid parts. Fused deposition modeling (FDM) and direct writing (DIW) are both typical material extrusion 3D printing methods. FDM is a method in which filamentary materials are heated, melted and extruded in a nozzle. The nozzle moves along the cross-sectional profile of the part, depositing the material on the substrate in a specific shape. The material quickly cools and solidifies to form the designed structure. DIW is a method in which a slurry with a certain viscosity is extruded from a nozzle by the pressure generated by air pressure, a plunger or a screw, and a specific structure is deposited on the substrate in a direction by controlling the movement of the nozzle and the substrate.

[0003] In the slurry type extrusion 3D printing process, as the solid content in the slurry continues to increase, the current extrusion 3D printing nozzle structure has problems such as poor printing uniformity and easy clogging. Due to the high content of solid particles in high-solid slurry, during the pressurized extrusion process, as the pressure rises, the slurry packing density increases, the friction and collision probability between solid particles increases, and the liquid phase precipitates, resulting in poor uniformity of nozzle structure printing; even more, after the extrusion pressure rises to a certain value, the solid particles focus in the nozzle, bite each other, block the nozzle, and cause printing interruption. This situation is particularly obvious when printing high-solid slurry, especially in 3D printing of energetic materials. In severe cases, energetic solid particles will undergo dry friction in the nozzle, causing safety accidents. Summary of the invention

[0004] In view of the shortcomings of the prior art that, during the pressurized extrusion process, as the pressure rise increases, the slurry packing density increases, the friction and collision probability between solid particles increases, and the liquid phase precipitates, resulting in poor uniformity of nozzle structure printing and easy clogging. The present invention proposes a nozzle structure optimization method, system and device for high-solid phase slurry extrusion. By simulating the high-solid phase slurry extrusion 3D printing process, the pressure, velocity field and particle distribution field of the initial extrusion process are obtained, and the nozzle structure characteristic parameters are selected as control variables based on the simulation results. The nozzle structure parameter variables are optimized with the minimum pressure drop at the nozzle inlet and outlet as the optimization criterion, and a parameter optimization group is obtained, thereby solving the problems existing in the prior art.

[0005] A nozzle structure optimization method for high solid phase slurry extrusion comprises the following steps:

[0006] Obtaining rheological parameters of the high solid phase slurry to be extruded; the rheological parameters include slurry viscosity and modulus;

[0007] The variation curves of slurry viscosity and modulus with shear rate and loading time were fitted with the rheological constitutive model suitable for high solid phase slurry to construct a rheological model.

[0008] The historical nozzle structure parameters were selected as the initial nozzle structure parameters, and the initial nozzle structure model was established for simulation analysis to determine the boundary parameters of the nozzle during high solid phase slurry extrusion in the simulation process.

[0009] The boundary parameters are input into the rheological model to obtain the pressure, velocity field and particle distribution field of the initial extrusion process of high solid phase slurry;

[0010] According to the pressure, velocity field and particle distribution field of the initial extrusion process, the nozzle structure parameters are selected as the control variables, and the minimum pressure drop between the extrusion input and output ends is taken as the optimization criterion to optimize the nozzle structure parameter variables and obtain the parameter optimization group;

[0011] The nozzle structure parameters with the smallest pressure drop in the parameter optimization group are selected to optimize the nozzle structure.

[0012] Furthermore, a plate shear rheometer, an extrusion rheometer or a rotational rheometer is used to obtain rheological parameters of the high solid phase slurry.

[0013] Furthermore, the variation curves of the slurry viscosity and modulus with shear rate and loading time are fitted with a rheological constitutive model suitable for high solid phase slurry to construct a rheological model, which specifically includes the following steps:

[0014] A rheological constitutive model of a high solid phase slurry is selected according to a non-Newtonian fluid model; the rheological constitutive model includes a Bird-Carreau constitutive model, a Cross-Williamson constitutive model or a Carreau-Yasuda constitutive model;

[0015] The rheological curve constructed according to the rheological performance parameters is fitted with the rheological constitutive model to obtain the control parameters for rheological model construction, and then the rheological model is constructed.

[0016] Furthermore, an initial nozzle structure model is established by three-dimensional modeling software for simulation analysis to determine the boundary parameters of the simulation process; wherein the determination of the boundary parameters of the simulation process specifically includes the following steps:

[0017] Establish the physical model of slurry extrusion mechanism and slurry extrusion flow field model;

[0018] The physical model of the slurry extrusion mechanism and the slurry extrusion flow field model are imported into the slurry rheology model. According to the actual extrusion process, the boundary conditions are set to calculate the slurry pressure, velocity, viscosity and particle distribution field boundary parameters of the extrusion process; the boundary conditions include the pressure and velocity of the extrusion inlet and outlet.

[0019] Furthermore, the slurry extrusion mechanism includes a pneumatic extrusion mechanism, a plunger extrusion mechanism or a screw extrusion mechanism; the simulation process boundary of the pneumatic extrusion mechanism is the inlet pressure condition; the simulation process boundary of the plunger extrusion mechanism is the inlet speed boundary; the simulation process boundary of the screw extrusion mechanism is the inlet screw rotation speed boundary; wherein the inner diameter range of the barrel used in conjunction with the slurry extrusion mechanism is 30 to 50 mm, the inlet pressure of the pneumatic extrusion mechanism is set to 0.2 to 2 MPa, the inlet speed of the plunger extrusion mechanism is set to 2 to 10 mm / s, and the inlet screw rotation speed of the screw extrusion mechanism is set to 5 to 60 rpm.

[0020] Furthermore, the nozzle structural parameters include the inlet diameter of the extrusion nozzle, the length of the contraction section, the angle of the contraction section, and the outlet diameter of the nozzle, wherein the outlet diameter of the nozzle ranges from 1 to 2 mm.

[0021] Furthermore, the response surface analysis method, orthogonal experimental method, covariance analysis method or principal component analysis method are used to optimize the nozzle structure parameter variables to obtain a parameter optimization group.

[0022] The present invention also includes a nozzle structure optimization system for high solid phase slurry extrusion, comprising:

[0023] An acquisition module, used to acquire rheological performance parameters of the high solid phase slurry to be extruded; the rheological performance parameters include slurry viscosity and modulus;

[0024] The model building module is used to fit the variation curves of slurry viscosity and modulus with shear rate and loading time with the rheological constitutive model suitable for high solid phase slurry to build a rheological model;

[0025] The boundary parameter determination module is used to select the historical nozzle structure parameters as the initial nozzle structure parameters, establish the initial nozzle structure model for simulation analysis, and determine the boundary parameters of the nozzle during high solid phase slurry extrusion in the simulation process;

[0026] The simulation module is used to input boundary parameters into the rheological model to obtain the pressure, velocity field and particle distribution field of the initial extrusion process of high solid phase slurry;

[0027] The optimization parameter acquisition module is used to select the nozzle structure parameters as the control variables according to the pressure, velocity field and particle distribution field of the initial extrusion process, to obtain the minimum pressure drop between the extrusion input end and the output end as the optimization criterion, to optimize the nozzle structure parameter variables and obtain the parameter optimization group;

[0028] The optimization module is used to select the nozzle structure parameters with the smallest pressure drop in the parameter optimization group and optimize the nozzle structure.

[0029] The present invention also includes a computer device for optimizing the nozzle structure for high-solid phase slurry extrusion, comprising: a memory, a processor, and a computer program stored in the memory, and when the processor executes the computer program, the steps of the nozzle structure optimization method for high-solid phase slurry extrusion are implemented.

[0030] The present invention also includes a readable storage medium, which stores a computer program. The computer program includes program instructions. When the program instructions are executed by a processor, they are used to execute the steps of the nozzle structure optimization method for high-solid phase slurry extrusion.

[0031] The present invention provides a nozzle structure optimization method, system and device for high solid phase slurry extrusion, which has the following beneficial effects:

[0032] The present invention constructs a rheological model according to the rheological performance parameters of high-solid phase slurry, selects the nozzle structure parameters used in the previous high-solid phase slurry extrusion as the initial nozzle structure parameters, establishes the initial nozzle structure model for simulation analysis, and determines the pressure, velocity field and particle distribution field of the initial extrusion process of the high-solid phase slurry through simulation. In order to avoid the increase in slurry packing density caused by the increase in pressure rise during the extrusion process, the increase in the probability of friction and collision between solid phase particles, and the precipitation of liquid phase, which lead to the deterioration of the final slurry uniformity and easy clogging, the nozzle structure parameter variables are optimized with the minimum pressure drop between the nozzle inlet and outlet as the optimization criterion, and the nozzle structure parameters with the minimum pressure drop are selected. This can effectively solve the problems of solid-liquid separation and nozzle clogging that are easy to occur in high-solid phase and high-viscosity slurry during extrusion 3D printing, and at the same time can ensure the uniformity of the high-solid phase slurry during the extrusion process. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a flow chart of a method for designing a minimum pressure drop nozzle structure suitable for high solid phase slurry extrusion 3D printing in an embodiment of the present invention;

[0034] Figure 2 Schematic diagram of the structural parameters of the extrusion nozzle suitable for high solid phase solid propellant slurry in the embodiment of the present invention

[0035] Figure 3The graphs are rheological property curves and Bird-Carreau constitutive model fitting curves of three solid propellant slurries with solid contents of 84wt%, 86wt% and 88wt% respectively in the embodiments of the present invention;

[0036] Figure 4 The pressure cloud map, velocity cloud map and viscosity cloud map obtained by simulating the solid propellant slurry with a solid content of 84wt% in the embodiment of the present invention;

[0037] Figure 5 is a response surface diagram of the interaction of nozzle structural parameters on pressure drop in an embodiment of the present invention;

[0038] Figure 6 This is a schematic diagram of the structure of an extrusion nozzle suitable for high solid phase solid propellant slurry before optimization in an embodiment of the present invention;

[0039] Figure 7 Schematic diagram of the optimized structure of the extrusion nozzle suitable for high solid phase solid propellant slurry in an embodiment of the present invention.

[0040] In the figure: a-nozzle height; b-nozzle upper end reduction angle; c-nozzle initial reduction inner diameter; d-nozzle final reduction inner diameter, e-flange connection hole. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0042] The present invention proposes a nozzle structure optimization method for high solid phase slurry extrusion, such as Figure 1 As shown; the method specifically comprises the following steps:

[0043] S1. Obtaining rheological parameters: performing rheological property tests on the high solid slurry to be extruded to obtain corresponding rheological property parameters.

[0044] High solid phase slurry includes but is not limited to solid propellant slurry, ceramic slurry, biological ink, metal slurry, etc. suitable for 3D printing.

[0045] The rheological curve is a curve showing the change of slurry viscosity and modulus with shear rate and loading time, which can be obtained using a flat plate shear rheometer, an extrusion rheometer, or a rotational rheometer. The rheological properties are the changing relationship between the slurry viscosity, modulus, shear rate, and loading time.

[0046] S2. Establishment of rheological model: Select the rheological constitutive model suitable for the high solid phase slurry, perform constitutive fitting based on the measured rheological curve, and obtain the rheological model control parameters.

[0047] The establishment of the rheological constitutive model of high solid phase slurry is selected according to the non-Newtonian fluid model; the rheological constitutive model includes but is not limited to the Bird-Carreau constitutive model, the Cross-Williamson constitutive model, and the Carreau-Yasuda constitutive model, and the rheological constitutive control equation can be obtained based on the rheological test experimental data; in a stable flow environment, the selected rheological constitutive model can accurately fit the rheological characteristic curve of the slurry.

[0048] S3. Extrusion 3D printing process simulation: Design the initial nozzle structure parameters, determine the simulation process boundary parameters, substitute them into the rheological model, and obtain the pressure, velocity field and particle distribution field of the initial extrusion process.

[0049] S3.1. Select the initial nozzle structure parameters based on the commonly used nozzles for high solid phase slurry extrusion 3D printing, establish the initial nozzle structure model through 3D modeling software, and perform simulation analysis.

[0050] S3.2. During the simulation process, a physical model of the slurry extrusion mechanism and a slurry extrusion flow field model are established, and a slurry rheology model is imported. According to the actual extrusion process, boundary conditions such as pressure and velocity at the extrusion inlet / outlet are set, and the slurry pressure distribution cloud map, velocity cloud map, viscosity cloud map and particle distribution field cloud map of the extrusion process are calculated.

[0051] The optional extrusion mechanisms include pneumatic extrusion mechanism, plunger extrusion mechanism and screw extrusion mechanism; the simulation process boundary of the pneumatic extrusion mechanism is the inlet pressure condition; the simulation process boundary of the plunger extrusion mechanism is the inlet velocity boundary; the simulation process boundary of the screw extrusion mechanism is the inlet screw rotation speed boundary; the inner diameter range of the barrel used in conjunction with the extrusion mechanism is 30-50mm, the inlet pressure of the pneumatic extrusion mechanism is set to 0.2-2MPa; the inlet velocity of the plunger extrusion mechanism is set to 2-10mm / s; the inlet screw rotation speed of the screw extrusion mechanism is set to 5-60rpm. During the simulation analysis, in addition to the boundary conditions, the parameters that need to be set should also include the rheological parameters of the slurry, the simulation step size and the number of iterations.

[0052] S4. Optimization design: Based on all preliminary simulation results, the characteristic parameters of the nozzle structure are selected as control variables, and the minimum pressure drop between the extrusion input and output ends is taken as the optimization criterion. The nozzle structure parameter variables are optimized to obtain the parameter optimization group.

[0053] S4.1. Based on the initial simulation results, the characteristic parameters of the nozzle structure are selected as control variables. The structural parameters are the inlet diameter c of the extrusion nozzle, the length l of the contraction section, the angle of the contraction section, the outlet diameter d of the nozzle, etc., where the outlet diameter d of the nozzle ranges from 1 to 2 mm. Under the planning of the optimization algorithm, different parameters are combined, and the simulation calculation method is used to obtain the pressure conditions at the nozzle inlet and outlet under different parameter groups. By comparing the simulation calculation results, the nozzle structure parameter design set with the minimum pressure drop at the nozzle inlet and outlet is obtained.

[0054] S4.2. Taking the minimum pressure drop between the nozzle inlet and outlet as the optimization goal, the optimization algorithm is used to optimize the nozzle model to obtain the optimal combination of nozzle structural parameters; during the optimization design process, the optimization algorithm includes but is not limited to response surface analysis, orthogonal experimental method, covariance analysis method, and principal component analysis method; the nozzle structural parameter optimization group includes but is not limited to the nozzle inlet diameter, outlet diameter and intermediate transition section size.

[0055] Experimental verification: The pressure difference between the extrusion input and output ends in the parameter optimization group was compared and analyzed by in-situ pressure measurement experiment to clarify the optimal structural parameters. According to the nozzle structural parameters obtained by simulation calculation, the corresponding nozzle structure was processed, and the in-situ pressure measurement test during the extrusion process was used to obtain the nozzle outlet pressure value under the same extrusion process and different structural parameters. Through experimental comparison of the outlet pressure values ​​of different nozzles, the nozzle structure with the smallest pressure drop was selected to complete the optimization design.

[0056] Based on the concept of the present invention, an embodiment is proposed, a method for designing a minimum pressure drop nozzle structure suitable for high solid phase slurry extrusion 3D printing, which specifically includes the following steps:

[0057] (1) A photocuring-assisted direct writing molding device is used, the extrusion mechanism is a plunger extrusion mechanism, and the high solid phase slurry is a solid propellant slurry suitable for 3D printing. There are three types of slurries used, and the solid phase contents are 84wt%, 86wt%, and 88wt%, respectively. The specific formula of the slurry is shown in Table 1.

[0058] Table 1 Formulas of solid propellant slurries with three solid contents

[0059]

[0060] (2) The rheological properties of solid propellant slurries were tested using a rotational rheometer to obtain the viscosity and modulus of the three solid propellant slurries as a function of shear rate and loading time. The specific rheological curves are shown in Figure 3 .

[0061] (3) Based on the characteristics of the plunger extrusion process with a large shear rate at the nozzle, the Bird-Carreau constitutive model is used to describe the rheological properties of the solid propellant slurry. The rheological performance curves of three solid propellant slurries with solid content of 84wt%, 86wt%, and 88wt% are shown in the figure below: Figure 3 The Bird-Carreau model parameter definitions and fitting results are shown in Table 2.

[0062] Table 2 Bird-Carreau model parameter definitions and fitting results

[0063]

[0064] (4) The initial nozzle structural parameters are selected as nozzle height a = 25 mm, nozzle initial contraction inner diameter c = 10 mm, nozzle final contraction inner diameter d = 1.8 mm, and it is known that the inner diameter of the barrel of the equipment used is 50 mm, and the nozzle is connected to the upper barrel by a flange. Solidworks software is used to perform three-dimensional solid modeling of the slurry flow field.

[0065] (5) The Polyflow software in Ansys was used to simulate and analyze the extrusion process of a solid propellant slurry plunger with a solid content of 84wt%. The slurry flow field and the plunger model were meshed using Ansys ICEM, and the inlet, outlet and wall of the slurry flow field were set. Polyfus e was then used to merge the meshes of the slurry flow field model and the plunger model, and the solution was calculated in the Polyflow software. The parameter settings are shown in Table 3. Finally, the slurry pressure distribution cloud map, velocity cloud map, viscosity cloud map and solid phase particle distribution field cloud map of the extrusion process were obtained; the simulation results of the solid propellant slurry with a solid content of 84wt% are as follows Figure 4 Shown are the pressure nephogram (a), velocity nephogram (b) and viscosity nephogram (c).

[0066] Table 3 Simulation analysis parameter settings

[0067]

[0068] (6) According to the initial simulation results, the nozzle height a, the upper end reduction angle b and the initial contraction inner diameter c of the nozzle structure characteristic parameters are selected as the parameters to be optimized. The inner diameter of the barrel of the known equipment is 50 mm. In order to meet the adaptation of the relevant dimensions of the upper end barrel at the flange connection and meet the forming accuracy and efficiency, the value range of each parameter to be optimized is determined, among which the value range of the nozzle height a is 10-30 mm, the value range of the upper end reduction angle b is 60-120°, and the value range of the initial contraction inner diameter c of the nozzle is 3-10 mm. The central combination (Box-Behnken) experimental design method is selected with a, b, and c as variables. Finally, it is determined that the design point falls on the combination of the high and low factor levels and their center points of the parameters to be optimized, and 13 groups of parameter combinations are obtained, as shown in Table 4. The 13 groups of parameter combinations are modeled and simulated respectively, and the simulated pressure drop values ​​of the nozzle under the 13 groups of parameter combinations are obtained. The experimental data are subjected to multivariate regression analysis by Design Expert software to establish a regression model for response surface fitting, and several parameter optimization groups are obtained. When fitting, a and b, a and c, and b and c are used as interaction terms to obtain the response surface diagram of the interaction of nozzle structure parameters on pressure drop, such as Figure 5 As shown, the influence weight of the structural characteristic parameters on the nozzle inlet and outlet pressure drop is analyzed and obtained. In this embodiment, the nozzle initial shrinkage inner diameter c has the greatest influence on the pressure drop, the nozzle height a is the second, and the upper end shrinkage angle b has the least influence.

[0069] Table 4 1.8mm diameter nozzle structure parameter combination

[0070]

[0071] (7) The nozzle with a diameter of 1.8 mm was designed according to the obtained parameter optimization group structure, processed by laser powder bed fusion forming (LPBF) process and then polished, and the pressure monitoring experiment of the extrusion process was carried out by plunger extrusion equipment to obtain the optimized nozzle pressure drop value. By comparing the pressure drop values, the optimal structural parameters of the nozzle were determined as follows: nozzle height a = 10 mm, upper end reduction angle b = 88.5°, initial shrinkage inner diameter c = 7.8 mm, corresponding to the simulation pressure drop of 0.016 MPa, the actual pressure drop of the nozzle before optimization was 0.2 MPa, and the pressure drop of the nozzle after optimization was 0.028 MPa, which was about 86% lower than that before optimization; the extrusion nozzle suitable for high solid phase solid propellant slurry has a structure before optimization as shown in FIG. Figure 6 As shown, the optimized structure is as follows Figure 7 shown.

[0072] So far, the minimum pressure drop nozzle structure with a diameter of 1.8 mm suitable for high solid phase solid propellant slurry extrusion 3D printing is obtained. By analogy, a nozzle structure with a diameter of 1.0 to 2.0 mm can be designed, such as Figure 2 shown.

[0073] Based on the same inventive concept, the present invention also proposes a nozzle structure optimization system for high solid phase slurry extrusion, comprising:

[0074] The acquisition module is used to obtain rheological property parameters of the high solid phase slurry to be extruded.

[0075] The model building module is used to select the rheological constitutive structure of the high solid phase slurry according to the rheological performance parameters and build a rheological model.

[0076] The boundary parameter determination module is used to select the nozzle used in the previous high solid phase slurry extrusion 3D printing as the initial nozzle structure parameters, establish the initial nozzle structure model through the 3D modeling software for simulation analysis, and determine the boundary parameters of the simulation process.

[0077] The simulation module is used to input the boundary parameters of the simulation process into the rheological model to obtain the pressure, velocity field and particle distribution field of the initial extrusion process.

[0078] The optimization parameter acquisition module is used to select the nozzle structure characteristic parameters as control variables according to the pressure, velocity field and particle distribution field of the initial extrusion process, to obtain the minimum pressure drop between the extrusion input and output ends as the optimization criterion, to optimize the nozzle structure parameter variables, and to obtain the parameter optimization group.

[0079] The optimization module is used to compare and analyze the nozzle outlet pressure values ​​under the same extrusion process and different structural parameters in the parameter optimization group, select the nozzle structural parameters with the minimum pressure drop, and complete the optimization of the nozzle structure.

[0080] The present invention also proposes a computer device for optimizing nozzle structure for high solid phase slurry extrusion, comprising: a memory, a processor and a computer program stored in the memory, and when the processor executes the computer program, the steps of the nozzle structure optimization method for high solid phase slurry extrusion are implemented.

[0081] The present invention also provides a readable storage medium, which stores a computer program. The computer program includes program instructions. When the program instructions are executed by a processor, they are used to execute the steps of a nozzle structure optimization method for high-solid phase slurry extrusion.

[0082] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A nozzle structure optimization method for high solid phase slurry extrusion, characterized in that: The following steps are involved: Obtaining rheological parameters of the high solid phase slurry to be extruded; the rheological parameters include slurry viscosity and modulus; The variation curves of slurry viscosity and modulus with shear rate and loading time were fitted with the rheological constitutive model suitable for high solid phase slurry to construct a rheological model. The historical nozzle structure parameters were selected as the initial nozzle structure parameters, and the initial nozzle structure model was established for simulation analysis to determine the boundary parameters of the nozzle during high solid phase slurry extrusion in the simulation process. The boundary parameters are input into the rheological model to obtain the pressure, velocity field and particle distribution field of the initial extrusion process of high solid phase slurry; According to the pressure, velocity field and particle distribution field of the initial extrusion process, the nozzle structure parameters are selected as the control variables, and the minimum pressure drop between the extrusion input and output ends is taken as the optimization criterion to optimize the nozzle structure parameter variables and obtain the parameter optimization group; The nozzle structure parameters with the smallest pressure drop in the parameter optimization group are selected to optimize the nozzle structure to be optimized.

2. The nozzle structure optimization method for high solid phase slurry extrusion according to claim 1, characterized in that: The rheological performance parameters of the high solid phase slurry are obtained by using a flat plate shear rheometer, an extrusion rheometer or a rotational rheometer.

3. The nozzle structure optimization method for high solid phase slurry extrusion according to claim 1, characterized in that: The method of fitting the variation curves of the slurry viscosity and modulus with the shear rate and loading time with the rheological constitutive model suitable for high solid phase slurry to construct a rheological model specifically includes the following steps: A rheological constitutive model of a high solid phase slurry is selected according to a non-Newtonian fluid model; the rheological constitutive model includes a Bird-Carreau constitutive model, a Cross-Williamson constitutive model or a Carreau-Yasuda constitutive model; The rheological curve constructed according to the rheological performance parameters is fitted with the rheological constitutive model to obtain the control parameters for rheological model construction, and then the rheological model is constructed.

4. The nozzle structure optimization method for high solid phase slurry extrusion according to claim 1, characterized in that: The initial nozzle structure model is established by three-dimensional modeling software for simulation analysis, and the boundary parameters of the simulation process are determined; wherein the determination of the boundary parameters of the simulation process specifically includes the following steps: Establish the physical model of slurry extrusion mechanism and slurry extrusion flow field model; The physical model of the slurry extrusion mechanism and the slurry extrusion flow field model are imported into the slurry rheology model. According to the actual extrusion process, the boundary conditions are set to calculate the slurry pressure, velocity, viscosity and particle distribution field boundary parameters of the extrusion process; the boundary conditions include the pressure and velocity of the extrusion inlet and outlet.

5. The nozzle structure optimization method for high solid phase slurry extrusion according to claim 4, characterized in that: The slurry extrusion mechanism includes a pneumatic extrusion mechanism, a plunger extrusion mechanism or a screw extrusion mechanism; the simulation process boundary of the pneumatic extrusion mechanism is the inlet pressure condition; the simulation process boundary of the plunger extrusion mechanism is the inlet speed boundary; the simulation process boundary of the screw extrusion mechanism is the inlet screw rotation speed boundary; wherein the inner diameter range of the barrel used in conjunction with the slurry extrusion mechanism is 30 to 50 mm, the inlet pressure of the pneumatic extrusion mechanism is set to 0.2 to 2 MPa, the inlet speed of the plunger extrusion mechanism is set to 2 to 10 mm / s, and the inlet screw rotation speed of the screw extrusion mechanism is set to 5 to 60 rpm.

6. The nozzle structure optimization method for high solid phase slurry extrusion according to claim 1, characterized in that: The nozzle structural parameters include the inlet diameter of the extrusion nozzle, the length of the contraction section, the angle of the contraction section, and the outlet diameter of the nozzle, wherein the outlet diameter of the nozzle ranges from 1 to 2 mm.

7. The nozzle structure optimization method for high solid phase slurry extrusion according to claim 1, characterized in that: The response surface analysis method, orthogonal experimental method, covariance analysis method or principal component analysis method are used to optimize the nozzle structure parameter variables and obtain the parameter optimization group.

8. A nozzle structure optimization system for high solid phase slurry extrusion, characterized in that: include: An acquisition module, used to acquire rheological performance parameters of the high solid phase slurry to be extruded; the rheological performance parameters include slurry viscosity and modulus; The model building module is used to fit the variation curves of slurry viscosity and modulus with shear rate and loading time with the rheological constitutive model suitable for high solid phase slurry to build a rheological model; The boundary parameter determination module is used to select the historical nozzle structure parameters as the initial nozzle structure parameters, establish the initial nozzle structure model for simulation analysis, and determine the boundary parameters of the nozzle during high solid phase slurry extrusion in the simulation process; The simulation module is used to input boundary parameters into the rheological model to obtain the pressure, velocity field and particle distribution field of the initial extrusion process of high solid phase slurry; The optimization parameter acquisition module is used to select the nozzle structure parameters as the control variables according to the pressure, velocity field and particle distribution field of the initial extrusion process, to obtain the minimum pressure drop between the extrusion input end and the output end as the optimization criterion, to optimize the nozzle structure parameter variables and obtain the parameter optimization group; The optimization module is used to select the nozzle structure parameters with the smallest pressure drop in the parameter optimization group and optimize the nozzle structure.

9. A computer device for optimizing nozzle structure for high solid phase slurry extrusion, characterized in that: include: A memory, a processor and a computer program stored in the memory, wherein when the processor executes the computer program, the steps of the nozzle structure optimization method for high solid phase slurry extrusion according to any one of claims 1 to 7 are implemented.

10. A readable storage medium, characterized in that: The readable storage medium stores a computer program, which includes program instructions. When the program instructions are executed by a processor, they are used to execute the steps of the nozzle structure optimization method for high-solid phase slurry extrusion as described in any one of claims 1-7.

Images