Hydrocyclone structure optimization method based on coupling effect of virtual fluid and elastic body

Abstract

The present application belongs to the field of flow field simulation technology, and provides a method for optimizing the structure of a cyclone based on the coupling of a virtual fluid and an elastic body, comprising the following steps: setting the shape parameters of the cyclone, establishing an elastic body model of an underflow tube and setting its material parameters; calculating the steady-state flow field of a conventional fluid model in the cyclone; calculating the instantaneous flow field of the virtual fluid model in the cyclone in turn at each calculation moment in a preset time domain, calculating the elastic deformation of the underflow tube based on the coupling of the virtual fluid model and the elastic body model and updating the shape parameters of the underflow tube; optimizing the structure of the underflow tube of the cyclone or modifying the shape parameters and material parameters of the elastic body model of the underflow tube according to the elastic deformation of the underflow tube in a preset time domain and the flow field of the virtual fluid model therein. The method provided by the present application can efficiently and accurately simulate the coupling of the elastic underflow tube and the slurry, and provide data support for the optimization of the cyclone structure.

Description

Technical Field

[0001] The present application belongs to the technical field of flow field simulation, and specifically provides a cyclone structure optimization method based on the coupling effect of virtual fluid and elastic body. Background Art

[0002] The cyclone is a common separation and classification equipment. Its main structure includes a cylindrical section and a conical section arranged from top to bottom. The cylindrical section and the conical section are hollow inside for cyclone classification of slurry. The upper part of the cylindrical section is provided with a slurry feed pipe and an overflow pipe, and the bottom of the conical section is provided with an underflow pipe. When the slurry enters the cylindrical section through the feed pipe under pressure, it performs cyclone motion along the cyclone. During the motion, the solid particles in the slurry are subjected to different centrifugal forces due to their different sizes and densities. The larger and coarser particles are subjected to greater centrifugal forces, gradually approaching the inner wall of the cyclone, and passing through the conical section downward along the cylindrical section, and finally discharged from the underflow pipe; the smaller and finer solid particles are subjected to smaller centrifugal forces, are in the center of the cyclone, and move upward with the liquid flow, and finally discharged from the overflow pipe. As the slurry rotates inside the cyclone, it inevitably causes wear to the inside of the cyclone. Although it is possible to reduce wear and extend the service life by laying an inner lining such as wear-resistant rubber, high-aluminum wear-resistant ceramics or silicon carbide on the inner wall of the cyclone, the wear is reduced and the service life is extended. However, for the location of the underflow pipe, since it is necessary to discharge the solid separation products with coarse particles and high density, and as the cone section continues to shrink, the rotation speed of the slurry reaches the maximum at this location, so the internal wear of the underflow pipe is particularly serious. Without changing the rigid manufacturing material (such as stainless steel) of the underflow pipe body, the applicant tried to replace corundum ceramics, KM wear-resistant composite ceramics, polyurethane and other materials as wear-resistant linings. However, no matter what material is replaced, the wear-resistant layer of the lining will be severely damaged, and the underflow pipe components need to be replaced after about a month.

[0003] In order to solve the above problems, elastic materials such as wear-resistant rubber can be used instead of rigid materials such as stainless steel as the body of the underflow pipe. Due to its elastic deformation ability, it can shrink or expand according to the different flow rates and flow rates of the slurry, thereby effectively reducing the wear rate. At the same time, since its body is entirely made of wear-resistant materials, the body can be directly replaced after the wear reaches a certain level. Therefore, compared with the underflow pipe made of rigid materials, it has the advantages of long service life and easy maintenance.

[0004] At the same time, the use of elastic materials to manufacture underflow tubes will also bring new problems: the deformation of the elastomer may lead to flow instability, increasing the possibility of turbulent vortices and vortex rupture, which in turn affects the separation efficiency of the cyclone. Therefore, it is necessary to optimize the shape and material properties of the underflow tube based on the interaction between the elastic underflow tube and the slurry fluid to ensure that the wear resistance is improved while maintaining an efficient separation effect. However, since the slurry composition inside the cyclone is extremely complex, including liquid-solid-gas and other phase components, and with the cyclone separation, the proportion of each component changes continuously, which undoubtedly greatly increases the difficulty of analyzing its internal flow field. Summary of the invention

[0005] In order to solve the problems existing in the above-mentioned prior art, the present application provides a cyclone structure optimization method based on the coupling effect of virtual fluid and elastic body, which can efficiently and accurately calculate the slurry flow field inside the cyclone using elastic underflow pipe and its coupling effect with the underflow pipe, thereby providing effective data support for the optimization of the cyclone structure. The method includes the following steps:

[0006] S1, setting shape parameters of the cyclone, establishing an elastic body model of the underflow pipe and setting its material parameters, wherein the shape parameters of the cyclone include the inner wall geometry of the cylindrical section and the conical section, and the inner wall geometry and outer wall geometry of the underflow pipe;

[0007] S2, calculating the steady-state flow field of the conventional fluid model in the cyclone, wherein the conventional fluid model is subject to rigid boundary constraints of the cylindrical section, the conical section and the underflow pipe in the entire calculation domain;

[0008] S3, executing steps S31 to S32 in sequence at each moment in the preset time domain:

[0009] S31, determining the instantaneous flow field of the virtual fluid model in the cyclone at each calculation moment based on the improved transient NS and turbulence model, wherein the virtual fluid model is a mixed fluid model including liquid, solid and gas phases, and the equivalent density of the virtual fluid model at any position is determined by its flow velocity at the position and the inner diameter of the cyclone corresponding to the position;

[0010] S32, determining the elastic deformation of the underflow pipe at each calculation moment based on the coupling effect between the virtual fluid model and the elastic body model in the underflow pipe at the calculation moment and updating the shape parameters of the underflow pipe;

[0011] S4, if within a preset time domain, the elastic deformation of the underflow pipe and the flow field of the virtual fluid model therein meet the design indicators, the underflow pipe of the cyclone is structurally optimized based on the shape parameters and material parameters of the elastic model of the underflow pipe, otherwise the shape parameters and material parameters of the elastic model of the underflow pipe are modified and return to step S2.

[0012] The embodiment of the present application provides a cyclone structure optimization method based on the coupling effect of virtual fluid and elastomer. By constructing a virtual fluid model including liquid, solid and gas phases, and calculating the real-time flow field inside the cyclone according to the density change of each component caused by the change of velocity and inner diameter during the flow of the multiphase mixed fluid inside the cyclone, the physical image is clear, the calculation process is reasonable and efficient, and the conventional multi-step simulation method can overcome the problems of large difference from the actual physical process, complex calculation process and extremely large amount of calculation, which provides strong support for the optimization of the cyclone structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a structural diagram of a cyclone provided according to some embodiments;

[0014] Figure 2 A flowchart of a cyclone structure optimization method based on the coupling effect of a virtual fluid and an elastic body provided according to an embodiment of the present application;

[0015] Figure 3 is a schematic diagram of the mesh density of the virtual fluid model at different positions in the specific embodiment 1 of the present application;

[0016] Figure 4 Schematic diagram of flow velocity distribution of the internal flow field of the cyclone in the specific embodiment 1 of the present application;

[0017] Figure 5 It is a schematic diagram of the elastic deformation of the bottom flow pipe in the specific embodiment 1 of the present application. DETAILED DESCRIPTION

[0018] Hereinafter, the present application will be further described based on preferred embodiments with reference to the accompanying drawings.

[0019] Figure 1 A schematic diagram of the structure of a cyclone for mineral separation is shown in FIG. Figure 1As shown in the figure, the main structure of the cyclone is a hollow cylindrical section and a conical section. The upper part of the cylindrical section is provided with a feed pipe and an overflow pipe. The bottom of the conical section is connected to the underflow pipe. When the slurry enters the cylindrical section through the feed pipe under pressure, it performs a cyclone motion along the cyclone. During the motion, the solid particles in the slurry are subjected to different centrifugal forces due to their different sizes and densities. The larger and coarser particles are subjected to greater centrifugal forces, gradually approaching the inner wall of the cyclone, and passing through the conical section downward along the cylindrical section, and finally discharged from the underflow pipe; the smaller and finer particles are subjected to smaller centrifugal forces, are in the center of the cyclone, and move upward with the liquid flow, and finally discharged from the overflow pipe. As the slurry rotates inside the cyclone.

[0020] As described in the background technology, in order to improve the service life of the bottom flow pipe under the cyclone while ensuring the sorting effect, the bottom flow pipe under the cyclone can be set to an elastic material. To this end, it is necessary to accurately analyze the flow of the slurry in the cyclone, and reasonably optimize the bottom flow pipe structure (including shape and material) according to the analysis results. However, since the slurry is a complex fluid that includes liquid phase (liquid used to form a cyclone), solid phase (ore for sorting) and gas phase (external gas mixed into the slurry) components, and as it rotates, stratifies, ascends and descends inside the cyclone, the content of each phase component changes continuously. At the same time, the introduction of the elastic bottom flow pipe causes the interaction between the slurry fluid and the elastic body to occur at the bottom flow pipe, resulting in the flow field at this part being affected by the deformation of the elastic body. Therefore, the simulation of its flow field is much more complicated than the analysis of the flow field in conventional single-phase and two-phase component fluids and rigid containers.

[0021] In order to solve the above problems, the present application provides a cyclone structure optimization method based on the coupling effect of virtual fluid and elastic body, referring to Figure 2 In some embodiments, the optimization method comprises the following steps:

[0022] S1, setting shape parameters of the cyclone, establishing an elastic body model of the underflow pipe and setting its material parameters, wherein the shape parameters of the cyclone include the inner wall geometry of the cylindrical section and the conical section, and the inner wall geometry and outer wall geometry of the underflow pipe;

[0023] S2, calculating the steady-state flow field of the conventional fluid model in the cyclone, wherein the conventional fluid model is subject to rigid boundary constraints of the cylindrical section, the conical section and the underflow pipe in the entire calculation domain;

[0024] S3, executing steps S31 to S32 in sequence at each calculation moment in the preset time domain:

[0025] S31, determining the instantaneous flow field of the virtual fluid model in the cyclone at each calculation moment based on the improved transient NS and turbulence model, wherein the virtual fluid model is a mixed fluid model including liquid, solid and gas phases, and the equivalent density of the virtual fluid model at any position is determined by its flow velocity at the position and the inner diameter of the cyclone corresponding to the position;

[0026] S32, determining the elastic deformation of the underflow pipe at each calculation moment based on the coupling effect between the virtual fluid model and the elastic body model in the underflow pipe at the calculation moment and updating the shape parameters of the underflow pipe;

[0027] S4, if within a preset time domain, the elastic deformation of the underflow pipe and the flow field of the virtual fluid model therein meet the design indicators, the underflow pipe of the cyclone is structurally optimized based on the shape parameters and material parameters of the elastic model of the underflow pipe, otherwise the shape parameters and material parameters of the elastic model of the underflow pipe are modified and return to step S2.

[0028] The optimization method is described in detail below in conjunction with specific embodiments.

[0029] Step S1:

[0030] Step S1 is used to set the initial parameters of the structure of the cyclone and to establish an initial elastic body model of the underflow pipe.

[0031] As analyzed above, since the core purpose of the method provided in the present application is to select a reasonable shape and material to construct a new elastic underflow pipe according to the flow of slurry in the cyclone and its interaction with the underflow pipe, the calculation domain can be limited to the area defined by the cylindrical section, the conical section and the inner wall of the underflow pipe without affecting the simulation accuracy. Based on the above purpose, in some embodiments of the present application, the structural parameters of the cyclone include the shape parameters of the cylindrical section, the conical section and the underflow pipe of the cyclone, and the elastic material parameters of the underflow pipe.

[0032] Among them, since the shell of the metal material hardly deforms when the slurry flows inside the cylindrical section and the conical section, when simulating the slurry flow in the cylindrical section and the conical section, the above two parts can be regarded as rigid bodies, and their inner walls provide rigid constraints on the slurry model. Therefore, in the embodiments of the present application, the shape parameters of the cylindrical section and the conical section include the inner wall geometry of the cylindrical section and the conical section.

[0033] In some preferred embodiments, in order to improve the calculation accuracy, the feed pipe and the overflow pipe can be further included in the calculation domain, that is, the structural parameters of the cyclone also include the shape parameters of the feed pipe and the overflow pipe. Accordingly, in order to simplify the calculation, the feed pipe and the overflow pipe can also be regarded as rigid bodies, so their shape parameters only include the geometric shape of their inner walls.

[0034] The shape parameters of the underflow pipe include the geometric shapes of the inner and outer walls. That is, when elastic materials are used to construct the underflow pipe, the deformation caused by the coupling between the underflow pipe and the slurry cannot be ignored. Therefore, it is necessary to characterize its wall thickness and other characteristics through the geometric shapes of the inner and outer walls.

[0035] After completing the initial setting of the shape parameters of the underflow tube, the elastic body model of the underflow tube can be constructed. Specifically, the finite element model of the underflow tube can be established according to the shape parameters of the underflow tube, and the corresponding grid can be divided into the grid, and the material parameters of the model can be assigned by selecting the alternative elastic body properties, thereby completing the construction of the elastic underflow tube model to be analyzed. Accordingly, in an embodiment of the present application, the structure of the cyclone is optimized, that is, the shape and material of the elastic underflow tube are reasonably selected through flow field analysis, so as to extend the life of the underflow tube components while ensuring the sorting effect.

[0036] Step S2:

[0037] After obtaining a set of alternative cyclone shape parameters, the steady-state flow field of the conventional fluid model in the cyclone can be calculated through step S2. The purpose of this step is to obtain an initial flow field of the slurry flow (i.e., preliminarily determine the flow velocity of the slurry at various positions) to prevent the divergence of the calculation results that may occur when the transient NS equations are directly used to calculate the flow field.

[0038] In some optional embodiments, step S2 may be performed in a manner known to those skilled in the art. For example, the slurry at the feed pipe may be measured, and a conventional fluid model flowing in the cylindrical section, the conical section, and the underflow pipe may be constructed based on the measurement results, and the corresponding fluid parameters may be assigned to the conventional fluid model. The conventional fluid model may be meshed with a relatively coarse initial mesh density, and then the steady-state NS equation shown in the following formula may be solved by steady-state calculation with an appropriate number of steps to obtain a stable flow field as the initial state of the subsequent flow field simulation:

[0039] ,

[0040] In the above formula, is the density of the conventional fluid, is the flow velocity vector, is the flow field pressure, is the dynamic viscosity, is the external force (e.g. gravity), is the Hamiltonian operator, Represents divergence calculation.

[0041] It should be noted that in the embodiment of the present application, in step S2, it is not necessary to consider the coupling effect of the elastic structure introduced into the underflow pipe, that is, in step S2, the conventional fluid model is subject to the rigid boundary constraints of the cylindrical section, the conical section and the underflow pipe in the entire calculation domain.

[0042] Step S3:

[0043] Step S3 is the core step of flow field simulation, which is used to accurately simulate the evolution of the slurry flow field in the cyclone within a preset time domain based on the initial flow field obtained in step S2.

[0044] As analyzed above, the slurry that is constantly rotating in the cyclone includes solid, liquid and gas phase components. At the same time, under the centrifugal action, an obvious inner and outer stratified vortex is formed in the cyclone. The proportions of the components of each phase in the inner and outer cyclones are different, resulting in great differences in the slurry characteristics at different positions. Although in theory, the solid ore, liquid fluid and bubbles can be modeled and mixed with fine grids respectively, and then the conventional fluid mechanics numerical calculation method is used to gradually superimpose the effects of each phase for correction, for example, the transient NS model is first used to obtain the evolution of the flow field separately, and then the pseudo potential function is obtained. The gas-liquid two-phase force is calculated, or the method disclosed in Chinese invention patent CN118917241A is used to calculate the gas-liquid mixed flow field, and then the collision and migration process of the solid phase components are simulated in the liquid phase fluid that has considered the gas-liquid mixing, and the local flow field information containing the solid phase components is updated using algorithms such as the immersed boundary method. However, the above process is complex and the amount of calculation is extremely large. On the other hand, the staged superposition correction method is also quite different from the actual physical process of the interaction between the liquid-solid-gas three-phase components in the cyclone, and the accuracy of the simulation is difficult to guarantee.

[0045] The embodiment of the present application adopts a different technical route to simulate the evolution of the complex flow field of multiphase components in the cyclone. Specifically, it fuses the liquid, solid and gas components to form a mixed fluid model, thereby obtaining a virtual fluid model that macroscopically characterizes the overall equivalent density characteristics of the slurry in the cyclone. Then, at each calculation moment in the preset time domain, first, through step S31, the flow field distribution of the virtual fluid model at the calculation moment is obtained by using the improved transient NS and turbulence model (it should be noted that in step S31, the virtual fluid model is still in the entire calculation domain). Then, based on the calculation result, in step S32, the elastic model of the underflow tube is used to replace the rigid underflow tube, and then through the coupling effect of the virtual fluid and the elastic body, the stress and deformation of the elastic underflow tube and the flow field morphology after the reaction of the virtual fluid are obtained, and then the shape of the underflow tube is updated according to the deformation of the elastic model, and then the next calculation moment is entered, and the calculation of steps S31 to S32 is repeated using the underflow tube with the updated shape parameters until the calculation of the entire time domain is completed.

[0046] Obviously, this multiphase complex flow field simulation method has a simple calculation process and can effectively reduce the amount of calculation. Moreover, this simulation method is more in line with the real physical process of the interaction between the slurry and the cyclone, and can effectively improve the accuracy of the flow field analysis results.

[0047] Specifically, step S31 includes iteratively executing steps S311 to S314 at each calculation moment in a preset time domain until a convergence condition is met:

[0048] Step S311, solving the transient NS equation considering equivalent density as shown in the following formula:

[0049] (1)

[0050] in, is the time variable, is the equivalent density function of the virtual fluid model, , , , , The meaning of is the same as the corresponding term in the steady-state NS equation above. is the cyclone inner diameter variable, is the shear stress (the shear stress is a second-order tensor).

[0051] The two equations in formula (1) are the continuity equation and momentum equation of the virtual fluid. By observing the expression of the equivalent density in formula (1) and comparing it with the previous steady-state NS equation, it can be seen that in the embodiment of the present application, during the transient flow field calculation process, the equivalent density of each point in the virtual fluid model is It is not the density of the conventional fluid in step S2. That is, the equivalent density of the virtual fluid model at any position is determined by the flow velocity at that position and the inner diameter of the cyclone corresponding to that position.

[0052] In some embodiments, the equivalent density at each location It can be expressed in the following form:

[0053] (2)

[0054] in, , , are the original densities of the solid, liquid and gaseous substances that constitute the virtual fluid model, , , They are solid phase weight, liquid phase weight and gas phase weight respectively.

[0055] Furthermore, the solid phase weight and the liquid phase weight are shown as follows:

[0056] (3)

[0057] The gas phase weight is given by the following formula:

[0058] (4)

[0059] in, is the solid phase weight ratio correction coefficient, is the flow velocity of the virtual fluid model The influence index on the solid phase weight, is the inner diameter of the cyclone The influence index on the solid phase weight, Inner diameter Correction factor for solid phase weight, is the liquid phase weight ratio correction coefficient, is the flow velocity of the virtual fluid model The influence index on liquid phase weight, is the inner diameter of the cyclone The influence index on liquid phase weight, is the flow velocity of the virtual fluid model Correction factor for liquid phase weight, is the critical value of the solid phase weight.

[0060] The equivalent density represented by equations (2) to (4) reflects the following characteristics of the virtual fluid model:

[0061] First, the solid phase weight With the flow rate of the virtual fluid model The increase in the liquid phase weight is due to the increase in the diameter and the reduction in the inner diameter, which reflects the characteristics that the coarser and larger solid particles gradually gather in the peripheral high-speed rotating flow field and the conical section and bottom flow tube below the cyclone under the centrifugal action. With the flow rate of the virtual fluid model The decrease of the solid phase weight and the increase of the inner diameter reflect the characteristics of the liquid containing only fine solid particles gathering in the inner rotating flow field of the cyclone and moving upward. That is, the trend of the solid phase weight changing with the flow velocity of the virtual fluid model and the inner diameter of the cyclone is opposite to the trend of the liquid phase weight changing with the flow velocity of the virtual fluid model and the inner diameter of the cyclone.

[0062] Secondly, the gas phase weight The value of is based on the solid phase weight With liquid weight changes with the change of The value of is affected by the solid phase weight With liquid weight This is consistent with the actual state that the density characteristics of the actual slurry are mainly determined by the distribution of the liquid and the solid components therein, and the gaseous component plays a secondary role.

[0063] Finally, the solid phase weight increases to its critical value After that, the gas phase weight can be set to 0 to indicate that as the slurry moves toward the lower part of the cone section, the solid content gradually increases, causing the slurry density to rise, and the gaseous components in the slurry no longer move downward. At this time, the slurry can be regarded as consisting of liquid-solid two phases.

[0064] It can be seen that by reasonably setting the equivalent density of the virtual fluid model, the characteristics of the slurry at different positions inside the cyclone can be characterized more accurately, thereby providing effective support for the simulation of its flow field evolution.

[0065] Step S312, solve the following equation considering equivalent density: equation:

[0066] (5)

[0067] in, is the spatial coordinate, for exist The direction component, is the turbulent kinetic energy, is the specific dissipation rate, , They are , The effective diffusion rate, , They are , The dissipation term, for The cross diffusion term, , They are , The generated items, , They are , The source term.

[0068] The source term is related to the subsequent virtual fluid calculation results. It represents the influence of the solid, liquid and gas phases on the turbulent energy and dissipation rate in the flow field after they are equivalent to virtual fluids. Its expression is shown in the following formula:

[0069] (6)

[0070] In the formula, , are the correction coefficient and external force term respectively.

[0071] Step S313, updating the turbulent viscosity of the virtual fluid model based on the following formula:

[0072] (7)

[0073] in, is the turbulent viscosity of the virtual fluid model, , are the low Reynolds number correction factor and model constant, respectively, which can be based on , Calculate and determine (in some specific embodiments, , can be 0.98 and 0.32 respectively). is the strain rate, , is a mixed function, is the dynamic viscosity, To calculate the distance from the position to the wall.

[0074] Step S314, updating the equivalent density of the virtual fluid model based on the following formula:

[0075] (2).

[0076] The meaning and value selection of each term in the equivalent density formula shown in formula (2) have been introduced in detail in the previous article and will not be repeated here.

[0077] After obtaining the flow field state of the virtual fluid distributed in the cyclone at each moment in step S31, it can be used as the initial condition, and further in step S32, an elastic underflow tube is used to replace the rigidly constrained underflow tube to accurately simulate the coupling effect between the virtual fluid and the elastic underflow tube.

[0078] In some embodiments of the present application, step S32 can be implemented by jointly solving the D3Q27 model and the elastic body force deformation model in the LBM (Lattice Boltzmann Method). The D3Q27 model is a three-dimensional discrete velocity model, which contains 28 velocity directions, from 0 to 27, has good isotropy and numerical stability, and can be applied to the accurate simulation of multiphase complex flows.

[0079] Specifically, step S32 includes performing the following steps at each calculation moment in the preset time domain:

[0080] Step S321, using the calculation result of step S31 as the initial condition, the force exerted by the virtual fluid model on the elastic body model of the underflow pipe at the calculation moment is determined based on the D3Q27 model shown in the following formula:

[0081] (8)

[0082] in, is the spatial coordinate of the interface between the elastic body model of the bottom flow pipe and the virtual fluid model, for The force exerted by the virtual fluid model on the elastic model of the bottom flow pipe, is the interaction strength, is the initial value of density, For the virtual fluid model The real-time density value at The elastic body model of the underflow pipe is The deformation speed, For the virtual fluid model The flow rate at , Respectively velocity vectors and their weights, is the time step.

[0083] Step S322: determining the elastic deformation of the elastic body model of the underflow pipe based on the force exerted by the virtual fluid model on the elastic body model of the underflow pipe at the calculation moment.

[0084] Step S322 can be implemented by solving various elastic force deformation models known to those skilled in the art. For example, the elastic underflow pipe can be regarded as being surrounded by a flexible thin plate, and the elastic model can be calculated by solving the flexible plate force deformation model shown in the following formula: The elastic deformation produced by the action of:

[0085] (9)

[0086] In the above formula, is the density of the elastic body model of the underflow pipe, , are the coordinate variables of the elastic body model of the bottom flow pipe in the local coordinate system, are the stress components associated with tensile and shear deformations, is the stress component related to bending deformation.

[0087] Step S323: updating the shape parameters of the underflow pipe based on the elastic deformation of the elastic body model of the underflow pipe.

[0088] After obtaining the elastic deformation of the bottom flow tube through step S322, the shape parameters of the bottom flow tube can be updated in step S323, that is, the geometric shapes of the inner wall and the outer wall of the bottom flow tube are updated, and then the process returns to step S31, and the shape of the bottom flow tube after the updated shape is used to recalculate the virtual fluid flow field under the rigid constraint at the next calculation moment. The flow field evolution from the previous calculation moment to the next calculation moment can be performed using a time advancement scheme familiar to those skilled in the art. For example, an explicit method can be used to directly use the result of the previous calculation moment as the initial value of the next calculation moment, or an implicit method can be used to determine the initial value of the next calculation moment through internal iteration.

[0089] In addition to the need to use different constraints in different steps, the setting of the grid density will also affect the calculation speed and calculation accuracy. Since the role of step S31 is to provide initial conditions for the fine correction of step S32, the grid density of the former can be set to be smaller (for example, set to the same as the initial grid density in step S2, or slightly larger than the initial grid density), so that it uses a coarser grid to calculate the initial conditions, while the grid density of the latter is set to be larger, that is, the flow field of the virtual fluid and the deformation of the elastic bottom flow tube are calculated with a finer grid, so as to comprehensively balance the calculation complexity and calculation accuracy. To this end, in some preferred embodiments of the present application, the virtual fluid model in step S31 is gridded according to the first grid density in the entire calculation domain; the part of the virtual fluid model in the elastic body model of the bottom flow tube in step S32 is gridded according to the second grid density, and the second grid density is greater than the first grid density. Correspondingly, the elastic body model of the bottom flow tube can also be gridded according to the second grid density to simplify the calculation complexity.

[0090] Since step S31 and step S32 use different grid densities to grid the model, and step S32 can further refine the time step, therefore, in some preferred embodiments, step S32 may also include a step of interpolating the calculation results of step S31 to obtain the boundary conditions of the coupling between the elastic body model and the virtual fluid model of the bottom flow pipe. Specifically, the calculation results of step S31 can be used as the initial conditions of the elastic bottom flow pipe area, and the boundary conditions of the area can be obtained using the spatial difference and time difference methods known to those skilled in the art to ensure that the elastic bottom flow pipe area and other areas match in time and space.

[0091] For example, in some specific embodiments, the following formula may be used for spatial interpolation and time difference:

[0092] ,

[0093] ,

[0094] in 、 Respectively represent the physical quantities that need to be differentiated in spatial position and time The interpolation results at each variable , , , , 、 、 、 They are only mathematical variables used for interpolation and have no physical meaning.

[0095] Step S4:

[0096] Back to Figure 2 , step S31 to step S32 will be repeated until the calculation of the entire time domain is completed, and then in step S4, the elastic deformation of the elastic underflow tube in the entire calculation domain and the changes in the flow field caused by it are evaluated according to the above calculation results. If the above elastic deformation and flow field changes meet the design indicators, the shape parameters and material parameters of the underflow tube set in step S1 can be used to design the elastic underflow tube, thereby realizing the structural optimization of the underflow tube; on the contrary, if the elastic deformation of the elastic underflow tube in the entire calculation domain and the changes in the flow field caused by it cannot meet the design indicators, for example, when the elastic modulus of the underflow tube is low, or the wall thickness is thin, the underflow tube is When the elastic underflow tube is too soft, although it can produce a large deformation when the underflow flows through, thereby reducing wear, it may cause flow field turbulence or lead to poor separation effect; for example, when the elastic modulus of the underflow tube is large and the wall thickness is thick, although the underflow may be relatively stable, due to its small deformation, the coupling effect between the high-speed slurry and the underflow tube may still cause serious wear to the underflow tube, that is, the meaning of replacing the elastic material is lost. When the above situation occurs, the shape parameters and material parameters of the elastic body model of the underflow tube can be modified in step S4, and then return to step S2 to recalculate until more suitable shape parameters and material parameters of the elastic underflow tube are searched. Specific embodiment 1:

[0098] This specific embodiment uses Figure 2 The method shown simulates the internal flow field of the cyclone using an elastic underflow tube, and optimizes the structure of the elastic underflow tube based on the simulation results, wherein the liquid phase component uses caustic Na2O, the solid phase component uses bauxite particles, and the initial density is the original density of the single-phase component, which is proportioned according to the test results at the feed inlet, and the initial density of the gas phase component uses the air density.

[0099] Figure 3 The figure shows the meshing of the virtual fluid model inside the cyclone at different locations. Figure 3 As shown, a coarser first grid density is used for grid division in the cylindrical section and the conical section, and a denser second grid density is used for grid division in the underflow pipe area.

[0100] Figure 4 The figure shows the flow field velocity distribution diagram inside the cyclone at a certain moment after the elastic bottom flow tube is used. Figure 5 The schematic diagram of the elastic deformation of the underflow pipe at a certain moment from multiple perspectives is shown. Figure 4 , Figure 5 As shown, the method provided in the present application can accurately analyze the coupling effect between the elastic structure at the bottom flow pipe and the slurry fluid, thereby providing effective data support for the optimization of the cyclone structure.

[0101] The above is a detailed introduction to the specific implementation methods of the present application. For those skilled in the art, several improvements and modifications may be made to the present application without departing from the principles of the present application. These improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A cyclone structure optimization method based on the coupling effect of virtual fluid and elastic body, characterized in that: The following steps are involved: S1, setting shape parameters of the cyclone, establishing an elastic body model of the underflow pipe and setting its material parameters, wherein the shape parameters of the cyclone include the inner wall geometry of the cylindrical section and the conical section, and the inner wall geometry and outer wall geometry of the underflow pipe; S2, calculating the steady-state flow field of the conventional fluid model in the cyclone, wherein the conventional fluid model is subject to rigid boundary constraints of the cylindrical section, the conical section and the underflow pipe in the entire calculation domain; S3, executing steps S31 to S32 in sequence at each calculation moment in the preset time domain: S31, determining the instantaneous flow field of the virtual fluid model in the cyclone at each calculation moment based on the improved transient NS and turbulence model, wherein the virtual fluid model is a mixed fluid model including liquid, solid and gas phases, and the equivalent density of the virtual fluid model at any position is determined by its flow velocity at the position and the inner diameter of the cyclone corresponding to the position; S32, determining the elastic deformation of the underflow pipe at each calculation moment based on the coupling effect between the virtual fluid model and the elastic body model in the underflow pipe at the calculation moment and updating the shape parameters of the underflow pipe; S4, if within a preset time domain, the elastic deformation of the underflow pipe and the flow field of the virtual fluid model therein meet the design indicators, the underflow pipe of the cyclone is structurally optimized based on the shape parameters and material parameters of the elastic model of the underflow pipe, otherwise the shape parameters and material parameters of the elastic model of the underflow pipe are modified and return to step S2.

2. The method for optimizing the hydrocyclone structure based on the coupling effect of virtual fluid and elastic body according to claim 1, characterized in that: The steady-state flow field of the conventional fluid model in the cyclone is obtained based on solving the steady-state NS equations.

3. The method for optimizing the hydrocyclone structure based on the coupling of virtual fluid and elastic body according to claim 1, characterized in that: In step S31, at each calculation moment, the instantaneous flow field of the virtual fluid model in the cyclone is constrained by the rigid boundaries of the cylindrical section, the conical section and the underflow pipe in the entire calculation domain.

4. The method for optimizing the hydrocyclone structure based on the coupling effect of virtual fluid and elastic body according to claim 1, characterized in that: Step S31 includes iteratively executing steps S311 to S314 at each calculation moment in a preset time domain until a convergence condition is met: Step S311, solving the transient NS equation considering equivalent density as shown in the following formula: ， in, is the time variable, is the equivalent density function of the virtual fluid model, is the flow velocity vector, is the cyclone inner diameter variable, is the flow field pressure, is the shear stress term, is the external force term, is the Hamiltonian operator, represents divergence calculation; Step S312, solve the following equation considering equivalent density: equation: ， in, is the spatial coordinate, for exist The direction of the component, is the turbulent kinetic energy, is the specific dissipation rate, , They are , The effective diffusion rate, , They are , The dissipation term, for The cross diffusion term, , They are , The generated items, , They are , The source term is expressed as follows: ， In the formula, , are the correction coefficient and external force term respectively; Step S313, updating the turbulent viscosity of the virtual fluid model based on the following formula: ， in, is the turbulent viscosity of the virtual fluid model, , are the low Reynolds number correction coefficient and model constant, respectively. is the strain rate, , is a mixed function, is the dynamic viscosity, To calculate the distance from the position to the wall; Step S314, updating the equivalent density of the virtual fluid model based on the following formula: ， in, , , are the original densities of the solid matter, liquid matter and gaseous matter constituting the virtual fluid model, respectively, , , They are solid phase weight, liquid phase weight and gas phase weight respectively.

5. The method for optimizing the structure of a cyclone based on the coupling of a virtual fluid and an elastic body according to claim 4, characterized in that: The trend of the solid phase weight changing with the flow rate of the virtual fluid model and the inner diameter of the cyclone is opposite to the trend of the liquid phase weight changing with the flow rate of the virtual fluid model and the inner diameter of the cyclone, and, The value of the gas phase weight changes based on the changes of the solid phase weight and the liquid phase weight.

6. The method for optimizing the structure of a cyclone based on the coupling of a virtual fluid and an elastic body according to claim 5, characterized in that: The solid phase weight and liquid phase weight are shown in the following formula: ， in, is the solid phase weight ratio correction coefficient, is the flow velocity of the virtual fluid model The influence index on the solid phase weight, is the inner diameter of the cyclone The influence index on the solid phase weight, Inner diameter Correction factor for solid phase weight, is the liquid phase weight ratio correction coefficient, is the flow velocity of the virtual fluid model The influence index on liquid phase weight, is the inner diameter of the cyclone The influence index on liquid phase weight, is the flow velocity of the virtual fluid model Correction factor for liquid phase weight.

7. The method for optimizing the structure of a cyclone based on the coupling of a virtual fluid and an elastic body according to claim 6, characterized in that: The gas phase weight is shown in the following formula: ， in, is the critical value of the solid phase weight.

8. The method for optimizing the structure of a cyclone based on the coupling of a virtual fluid and an elastic body according to claim 4, characterized in that: Step S32 includes performing the following steps at each calculation moment in the preset time domain: Step S321, using the calculation result of step S31 as the initial condition, the force exerted by the virtual fluid model on the elastic body model of the underflow pipe at the calculation moment is determined based on the following formula: ， in, is the spatial coordinate of the interface between the elastic body model of the bottom flow pipe and the virtual fluid model, for The force exerted by the virtual fluid model on the elastic model of the bottom flow pipe, is the interaction strength, is the initial value of density, For the virtual fluid model The real-time density value at The elastic body model of the underflow pipe is The deformation speed, For the virtual fluid model The flow rate at , Respectively velocity vectors and their weights, is the time step; Step S322, determining the elastic deformation of the elastic body model of the underflow pipe based on the force exerted by the virtual fluid model on the elastic body model of the underflow pipe at the calculation moment; Step S323: updating the shape parameters of the underflow pipe based on the elastic deformation of the elastic body model of the underflow pipe.

9. The method for optimizing the hydrocyclone structure based on the coupling of virtual fluid and elastic body according to claim 1, characterized in that: In step S31, the virtual fluid model is gridded in the entire computational domain according to a first grid density; In step S32, the portion of the virtual fluid model in the elastic body model of the underflow pipe is meshed according to a second mesh density, and the second mesh density is greater than the first mesh density.

10. The method for optimizing the structure of a cyclone based on the coupling of a virtual fluid and an elastic body according to claim 9, characterized in that: Step S32 also includes the step of interpolating the calculation result of step S31 to obtain the boundary conditions of the coupling effect between the elastic body model of the underflow pipe and the virtual fluid model.

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