Filter CFD-DEM coupling calculation method and system based on precise filtering medium

Abstract

The invention discloses a filter CFD-DEM coupling calculation method and system based on an accurate filtering medium, and belongs to the technical field of agricultural irrigation, the calculation method comprises a particle method and a wall surface method, and the use scene is related to the filtering medium; comprising the following steps: selecting a calculation model according to an actual model, establishing and calculating a fluid domain, establishing and setting a filter medium model, and performing CFD-DEM coupling calculation. The method is characterized in that geometric characteristics of the filter medium are accurately simulated, and calculation of interaction among particles, the filter medium and a wall surface is realized through a CFD-DEM coupling calculation method. The method is powerful in calculation function and excellent in simulation effect, consumes few calculation resources, and can be well applied to the design and development process of the filter.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural irrigation, and in particular relates to a filter CFD-DEM coupling calculation method and system based on precise filter media. Background Art

[0002] Agricultural filters are important components in agricultural irrigation systems and are basic measures to ensure the operation of irrigation systems. Modern agriculture often uses drip irrigation as an irrigation method. The drippers at the end of the drip irrigation system have a small diameter, low flow rate, and are easy to clog. When sandy water sources enter the drip irrigation system, coarse sand directly blocks the drippers, causing the drippers to fail. The accumulation of fine sediment in the drip irrigation system will also affect the hydraulic performance of the drippers and reduce the life of the drippers. At the same time, the sediment in the irrigation system is also a favorable condition for the attachment of microorganisms, which may cause further complex blockages. The sediment in the irrigation system is the root cause of the blockage phenomenon. In order to ensure the stable operation of the drip irrigation system, a filter must be used at the head of the irrigation system to filter the water source. Especially for areas where the water source contains a large amount of sand, filters often play a decisive role in the application of drip irrigation systems.

[0003] The structure of agricultural filters is relatively complex, and mold making and testing consume a lot of time and cost. Designers are often limited by this and find it difficult to obtain the optimal structure of the filter. Therefore, there is an urgent need for a numerical simulation method for the filter filtration process to help designers obtain the filter, especially the particle distribution of the filter mesh. However, the existing numerical methods for filter simulation often simplify the woven mesh into a punched mesh, and its simulation accuracy is seriously insufficient; at the same time, a large number of meshes cause the model grid scale to grow exponentially, and the resulting computational cost is also unacceptable. Designers often use scaled filter mesh models for research, which further reduces the simulation accuracy; finally, the existing numerical methods can only obtain the approximate spatial distribution of particles, and the interaction between particles and the filter mesh cannot be calculated at all. The existing numerical methods for filters cannot meet the needs of designers and fail to play a positive guiding role in the design of filters.

[0004] Therefore, a more accurate, convenient and intuitive simulation calculation method must be adopted to better simulate the filtering process of the filter. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a filter CFD-DEM coupling calculation method and system based on precise filter media in view of the deficiencies in the above-mentioned prior art, so as to solve the technical problem that the simulation calculation accuracy of the filter filtration process is low and difficult to apply.

[0006] The present invention adopts the following technical solutions: A CFD-DEM coupled calculation method for a filter based on precise filter media includes the following steps: S1. Perform an abstract analysis on the filter medium and determine the applicable calculation model; S2. Modeling the filter without filter media to obtain its flow field, wherein the use of the wall method requires additional porous media areas to be set in the flow field; S3, numerically simulate the filter flow field to obtain its flow state, and import it into the DEM calculation program; S4, modeling the filter medium and inserting the model into the flow field in the DEM calculation program; S5. Perform coupling calculation on the obtained CFD-DEM model to obtain the simulation result of the filter performance.

[0007] Preferably, in step S1, the filter screen and the laminated sheets with uniform thickness are simplified to a single-layer plate shell, and the particle method is used for simulation, and the perforated filter screen and the laminated sheets are simulated using the wall method.

[0008] Preferably, in step S2, the particle method is used to model the flow field, and the wall method is used to establish the flow field and filter medium models respectively.

[0009] Preferably, in step S3, when establishing the flow field model, a porous medium model is inserted into the filter medium region, and its coverage area and hydraulic performance parameters are the same as those of the filter medium that has not undergone the filtering process.

[0010] Preferably, in step S4, the particle method inserts a complete model of the filter medium into the fluid region through custom particles and custom inlets.

[0011] Preferably, in step S4, the wall method inserts the complete model of the filter medium into the fluid region by inserting the wall.

[0012] Preferably, in step S5, for unidirectional coupling, the distribution and quantity of particles driven by the fluid on the filter medium at the initial stage of filtration are calculated; for bidirectional coupling, the pressure rise during the filtration process and the pattern of filter cake formation are calculated.

[0013] In a second aspect, an embodiment of the present invention provides a filter CFD-DEM coupling calculation system based on a precise filter medium, comprising: The analysis module performs an abstract analysis on the filter medium and determines the applicable calculation model; The construction module is used to model the filter without filter media to obtain its flow field, where the use of the wall method requires additional porous media areas to be set in the flow field; The simulation module performs numerical simulation on the filter flow field to obtain its flow state and imports it into the DEM calculation program; A calculation module that models the filter medium and inserts this model into the flow field in the DEM calculation program; The output module performs coupling calculation on the obtained CFD-DEM model to obtain the simulation results of the filter performance.

[0014] In a third aspect, a computer device comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the above-mentioned filter CFD-DEM coupling calculation method based on precise filter media are implemented.

[0015] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, comprising a computer program, which, when executed by a processor, implements the steps of the above-mentioned filter CFD-DEM coupling calculation method based on precise filter media.

[0016] In a fifth aspect, a chip comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the above-mentioned filter CFD-DEM coupling calculation method based on precise filter media are implemented.

[0017] In a sixth aspect, an embodiment of the present invention provides an electronic device, including a computer program, which, when executed by the electronic device, implements the steps of the above-mentioned filter CFD-DEM coupling calculation method based on precise filter media.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects: For woven filter screens and laminated filter media with uniform thickness, the particle model used in the present invention accurately approximates the actual filter media and can reflect the characteristics of weaving and lamination; since the filter media is regarded as particles, the interaction between the sediment particles and the filter media can be calculated, including force, adhesion, friction, etc.

[0019] For perforated filter screens and general laminated filter media, the present invention simulates the flow field through a porous medium model and uses the wall surface to accurately approximate the filter medium, which can also reflect its shape and structural characteristics; compared with the particle model, it only cannot calculate the interaction between the particles and the medium, but its simulation effect is still much stronger than the existing technology.

[0020] Since the model is introduced step by step, the overall calculation is reduced from the exponential level to the linear level. At the same time, the CFD process is solved by the CPU, and the DEM process is solved by the GPU, which can fully utilize the computing resources. The simulation calculation time cost of the same case is reduced from several weeks to within a few days.

[0021] The present invention avoids the complicated pre- and post-processing steps in the traditional calculation method. Since the flow field model and the filter screen model are established separately, the time cost and equipment requirements for modeling are reduced. The calculation method of the present invention is simple, easy to learn and easy to operate, and its performance greatly exceeds the existing calculation method. It is currently the best calculation method for filters, especially agricultural filters.

[0022] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the principle and applicable model of the particle method; Figure 2 It is the schematic diagram of the principle and applicable model of the wall method; Figure 3 A schematic diagram of a single fiber for a custom woven filter; Figure 4 Create filter models for building with user-defined fiber particles; Figure 5 It is a simulation diagram of the filtration process of the braided filter; Figure 6 It is a schematic diagram of a ring-shaped simulated woven filter; Figure 7 Schematic diagram of the filtration process of the punched filter using the wall model; Figure 8 It is a schematic diagram of the simulated lamination filtering process using the wall model; Fig. 9 It is a schematic diagram of some contents that can be calculated by the present invention; Fig.10 A schematic diagram of a computer device provided by an embodiment of the present invention; Fig.11 A block diagram of a chip provided according to an embodiment of the present invention; Fig.12 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0026] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0027] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0028] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0029] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0030] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0031] The present invention provides a CFD-DEM coupling calculation method for a filter based on precise filter media, which includes selecting a calculation model, establishing and calculating a fluid domain, establishing and setting a filter media model, and CFD-DEM coupling calculation according to an actual model; the method is characterized in that the geometric features of the filter media are accurately simulated, and the calculation of the interaction between particles, the filter media, and the wall is realized through the CFD-DEM coupling calculation method. The present invention has powerful calculation functions, excellent simulation effects, and consumes less calculation resources, and can be well applied in the design and development process of filters.

[0032] See also Fig.12 The present invention provides a CFD-DEM coupling calculation method for a filter based on a precise filter medium, comprising the following steps: S1. Determine the calculation model to be used according to the difference of filter media; The particle method is used to simulate the woven filter screen and the laminated sheets with uniform thickness that can be simplified as a single-layer plate shell, and the wall method is used to simulate the perforated filter screen and the laminated sheets in general situations.

[0033] S2. Establish a three-dimensional computational model of the flow field; For the particle method described in step S1, only the flow field is modeled; For the wall method described in step S2, models of the flow field and the filter medium are established separately.

[0034] S3. Perform numerical simulation on the flow condition of the filter flow field based on CFD method; For the wall method in step S1, since the filter medium will be regarded as a wall inserted into the DEM calculation process and will not interact with the flow field during the coupling process, it is necessary to insert a porous medium model into the filter medium area when establishing the flow field model. Its coverage area and hydraulic performance parameters should be the same as those of the filter medium that has not undergone the filtration process.

[0035] S4. Perform calculation settings in DEM software; For the particle method, a complete model of the filter medium is inserted into the fluid region through custom particles and custom inlets; For the wall method, a complete model of the filter medium is inserted into the flow region by inserting the walls.

[0036] S5. Start unidirectional coupling or bidirectional coupling.

[0037] For one-way coupling, the distribution and quantity of particles driven by fluid on the filter medium at the initial stage of filtration can be obtained; For bidirectional coupling, the pressure rise during filtration and the pattern of filter cake formation can also be determined.

[0038] It should be noted that bidirectional coupling consumes more computational resources than unidirectional coupling.

[0039] For filters with different filter media, the general steps of simulation calculation are different, as shown in the following table:

[0040] See also Figure 1 The woven filter model applicable to the particle method refers to a mesh filter medium woven from wires of uniform wire diameter. The only requirement is that the cross-sectional shape of the wire should be circular, while the weaving method, weaving spacing, wire diameter of the same wire, and wire diameter of different wires can be different. The overall shape of the filter can also be changed arbitrarily, for example Figure 6 The annular woven filter shown. Woven filters with strip-shaped wires should be treated as punched filters.

[0041] The laminates with uniform thickness applicable to the particle method refer to laminates with surface curvature as the only feature, which can be modeled by stretching the surface curvature with uniform thickness. Laminates without this feature are called general laminates.

[0042] See also Figure 1 In the CFD calculation process of the particle method, the fluid domain does not contain any structure of the filter, but the modeling of the filter holder is sometimes necessary, especially when the holder has a greater impact on the flow field. In the DEM calculation process, the filter is inserted into the calculation domain by combining user-defined fibers and user-defined inlets.

[0043] When the particle filter is inserted into the calculation domain, it can interact with the flow field as a particle. At this time, the influence of the filter on the flow field will be automatically considered in the entire calculation process. Therefore, any structure of the filter can be excluded in the fluid domain modeling. In the CFD calculation, the energy model is not considered, and the continuity equation and mass conservation equation are used as its control equations, and the standard wall function is used. Turbulence model, its turbulent kinetic energy and turbulent dissipation rate The control equation is as follows:

[0044] in, is the term for the turbulent kinetic energy caused by the mean velocity gradient; is the term for the turbulent kinetic energy generated by buoyancy; is the pulsation expansion value caused by the influence of compressible turbulent pulsation expansion on the total dissipation rate; , , , , is the empirical constant contained in this type of equation; , is the turbulent Prandtl number; , For custom source items.

[0045] See also Figure 2 In the CFD calculation process of the wall method, the fluid domain must include a porous medium region to simulate the effect of the filter medium on the flow field in the initial state. The porous medium region is a type of fluid domain that contains resistance parameters. It ignores the specific geometric characteristics of the filter medium and retains its overall flow characteristics. For uniform porous media, the resistance expression formula is:

[0046] in, is the viscous drag coefficient, is the inertial drag coefficient, is the velocity in the i direction, is the molecular viscosity coefficient, is the fluid density, is a momentum sink, which can be obtained by Calculated. is the pressure gradient, is the thickness of the porous medium.

[0047] In the calculation, the resistance coefficient needs to be adjusted to make the flow condition of the flow field similar to the overall flow condition of the real filter medium. In the DEM calculation process, the actual filter condition is simulated by directly inserting the real model of the filter medium into the calculation domain; Specifically, since the wall inserted in the DEM process has no effect on the fluid domain, the fluid domain itself must contain a porous medium region. However, the particles blocked by the filter wall can still affect the fluid domain, so the wall method can still simulate the actual flow conditions well.

[0048] Since the fluid domain modeling of both methods does not involve complex structures, the calculation speed of the fluid domain flow field is fast and the convergence is stable. It should be noted that CFD and DEM calculations are separate processes, which are only connected to each other through the interaction between particles and flow fields. Therefore, the models and calculations of the CFD process and the DEM process can be considered separately. As long as the spatial distribution of the particles is correct, the accuracy of the CFD-DEM coupling can be guaranteed.

[0049] In the coupled calculation, the drag force on the particle is calculated by the Schiller & Naumann method, and its formula is as follows:

[0050] in, is the Reynolds number.

[0051] See also Figure 3 User-defined particles can be divided into user-defined fibers and user-defined plates and shells; user-defined fibers are models composed of nodes and , and the wire material of the real woven filter can be simulated through the fine arrangement of nodes and cylindrical particles; user-defined plates and shells are surface models with thickness, and the real laminates can be simulated by importing the surface and setting the thickness.

[0052] Specifically, the nodes of user-defined fibers can be arbitrarily distributed in space, and each cylindrical particle can only connect two nodes; the cross-sectional shape of each cylindrical particle is circular, and its diameter can be different. It should be noted that the nodes and cylindrical particles do not have to be connected end to end, and one node can connect multiple cylindrical particles, but in the actual definition process, it is necessary to avoid the intersection or interference of two cylindrical particles in space, otherwise it will cause distortion of calculation results and waste of calculation resources; the thickness characteristics of user-defined plates and shells are realized in the DEM process, and only two-dimensional surfaces are established during modeling, and no three-dimensional model is established.

[0053] See also Figure 4 By arranging, combining and rotating the user-defined particles according to a certain rule through the user-defined entrance, a filter medium model with a very high degree of simulation can be obtained. The woven filter model shown in the figure is the biggest advantage of this simulation method.

[0054] Specifically, for the particle method, since the model reflects the geometric characteristics of the filter medium very well, its simulation effect is significantly better than any existing model. Figure 5 In the woven filter filtration process shown, particles can be caught by the geometric structure of the mesh, which is consistent with the actual situation, while existing models are often driven by the fluid to slide in the filter area, causing distortion.

[0055] Forces acting on particles and filter screen The normal contact force is calculated using the linear spring-dashpot model:

[0056]

[0057] in, is the normal contact stiffness, is the normal damping coefficient, is the contact normal overlap, is the time derivative of the contact normal overlap, is the damping ratio, is the equivalent mass of the contact, which for this method is equal to the mass of the particle.

[0058] For this method it is equal to the mass of the particle The tangential contact force is calculated using the Coulomb limit model

[0059] in, is the friction coefficient, is the normal contact force, is the tangential component of the relative velocity vector.

[0060] Adhesion force is calculated using the constant adhesion force model

[0061] in, is the adhesion force, is the contact normal overlap, is the mass of the contact particle, is the acceleration due to gravity, is the specified distance, that is, the adhesion force is calculated if the distance is smaller than this distance. is the specified fraction, i.e. the ratio of adhesion force to gravity.

[0062] The contents that can be calculated in this method include: the force between particles and filter media, the force inside the filter media, the deformation of the filter media, the force between the filter media and the retaining frame, the wear and damage of the filter screen, etc.; because the filter screen is regarded as a fiber particle, its calculation accuracy exceeds that of the existing model.

[0063] In another embodiment of the present invention, a CFD-DEM coupled calculation system for a filter based on a precise filter medium is provided. The system can be used to implement the above-mentioned CFD-DEM coupled calculation method for a filter based on a precise filter medium. Specifically, the CFD-DEM coupled calculation system for a filter based on a precise filter medium includes an analysis module, a construction module, a simulation module, a calculation module and an output module.

[0064] Among them, the analysis module performs abstract analysis on the filter medium and determines the applicable calculation model; The construction module is used to model the filter without filter media to obtain its flow field, where the use of the wall method requires additional porous media areas to be set in the flow field; The simulation module performs numerical simulation on the filter flow field to obtain its flow state and imports it into the DEM calculation program; A calculation module that models the filter medium and inserts this model into the flow field in the DEM calculation program; The output module performs coupling calculation on the obtained CFD-DEM model to obtain the simulation results of the filter performance.

[0065] In another embodiment of the present invention, a terminal device is provided, the terminal device includes a processor and a memory, the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc., which is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions to implement corresponding method flows or corresponding functions; the processor described in the embodiment of the present invention can be used for the operation of the filter CFD-DEM coupling calculation method based on the precise filter medium, including: Abstract analysis is performed on the filter medium to determine the applicable calculation model; the filter without filter medium is modeled to obtain its flow field, where the use of the wall method requires additional porous medium areas to be set in the flow field; the filter flow field is numerically simulated to obtain its flow state and imported into the DEM calculation program; the filter medium is modeled and the model is inserted into the flow field in the DEM calculation program; the obtained CFD-DEM model is coupled to obtain the simulation results of the filter's filtration performance.

[0066] See also Fig.10 , the terminal device is a computer device. The computer device 60 of this embodiment includes: a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61. When the computer program 63 is executed by the processor 61, the method for calculating the composition of fluid in the reservoir transformation wellbore in the embodiment is implemented. To avoid repetition, it is not described one by one here. Alternatively, when the computer program 63 is executed by the processor 61, the functions of each model / unit in the CFD-DEM coupling calculation system of the filter based on the precise filter medium in the embodiment are implemented. To avoid repetition, it is not described one by one here.

[0067] The computer device 60 may be a computing device such as a desktop computer, a notebook, a PDA, or a cloud server. The computer device 60 may include, but is not limited to, a processor 61 and a memory 62. Those skilled in the art will appreciate that Fig.10This is only an example of the computer device 60 and does not constitute a limitation of the computer device 60. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the computer device may also include input and output devices, network access devices, buses, etc.

[0068] The processor 61 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0069] The memory 62 may be an internal storage unit of the computer device 60, such as a hard disk or memory of the computer device 60. The memory 62 may also be an external storage device of the computer device 60, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc., equipped on the computer device 60.

[0070] Furthermore, the memory 62 may include both an internal storage unit of the computer device 60 and an external storage device. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 may also be used to temporarily store data that has been output or is to be output.

[0071] See also Fig.11 , the terminal device is a chip, and the chip 600 of this embodiment includes a processor 622, which may be one or more, and a memory 632 for storing a computer program executable by the processor 622. The computer program stored in the memory 632 may include one or more modules, each corresponding to a set of instructions. In addition, the processor 622 may be configured to execute the computer program to execute the above-mentioned filter CFD-DEM coupling calculation method based on precise filter media.

[0072] In addition, the chip 600 may further include a power supply component 626 and a communication component 650, wherein the power supply component 626 may be configured to perform power management of the chip 600, and the communication component 650 may be configured to implement communication, for example, wired or wireless communication, of the chip 600. In addition, the chip 600 may further include an input / output interface 658. The chip 600 may operate based on an operating system stored in the memory 632.

[0073] In another embodiment of the present invention, the present invention also provides a storage medium, specifically a computer-readable storage medium, which is a memory device in a terminal device for storing programs and data. It can be understood that the computer-readable storage medium here can include both the built-in storage medium in the terminal device and the extended storage medium supported by the terminal device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and these instructions can be one or more computer programs. It should be noted that the computer-readable storage medium here can be a high-speed RAM memory, or a non-volatile memory (Non-VolatileMemory), such as at least one disk memory.

[0074] The processor may load and execute one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of the CFD-DEM coupling calculation method for the filter based on the precise filter medium in the above embodiment; the processor may load and execute the following steps: Abstract analysis is performed on the filter medium to determine the applicable calculation model; the filter without filter medium is modeled to obtain its flow field, where the use of the wall method requires additional porous medium areas to be set in the flow field; the filter flow field is numerically simulated to obtain its flow state and imported into the DEM calculation program; the filter medium is modeled and the model is inserted into the flow field in the DEM calculation program; the obtained CFD-DEM model is coupled to obtain the simulation results of the filter's filtration performance.

[0075] In order to make the purpose, 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 in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0076] See also Figure 7 and Figure 8 , by inserting perforated filter screens or general laminates into the computational domain through the wall normal, the geometric characteristics of the filter medium can be well reflected. Compared with the particle method, it lacks additional calculation content, but the simulation of the filtration process is equally realistic. The wall method can be regarded as an improvement on the existing method. Due to the introduction of the porous medium model, the flow field simulation in the coupling process is more accurate.

[0077] See also Fig. 9 The method of the present invention can be used to calculate the pressure drop change of the filter medium, the filtering performance of the particles, etc., and its general use can meet the needs of designers.

[0078] In summary, the present invention provides a CFD-DEM coupling calculation method and system for a filter based on precise filter media, which accurately simulates the filter media (filter screens, laminates, etc.) used by the filter to obtain its filtering effect. It can use fewer resources to accurately simulate and calculate large-scale, high-quantity mesh structures and particle structures. Compared with the existing technology, it has the advantages of high precision, easy use, and reasonable consumption of computing resources, and can provide effective computing support for filter structure design and actual production.

[0079] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0080] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0081] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in the present invention can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0082] In the embodiments provided by the present invention, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0083] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0084] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0085] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0086] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices, and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0087] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0088] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0089] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A CFD-DEM coupling calculation method for filters based on precise filter media, characterized in that: The following steps are involved: S1. Perform an abstract analysis on the filter medium and determine the applicable calculation model; S2. Modeling the filter without filter media to obtain its flow field, wherein the use of the wall method requires additional porous media areas to be set in the flow field; S3, numerically simulate the filter flow field to obtain its flow state, and import it into the DEM calculation program; S4, modeling the filter medium and inserting the model into the flow field in the DEM calculation program; S5. Perform coupling calculation on the obtained CFD-DEM model to obtain the simulation result of the filter performance.

2. The filter CFD-DEM coupling calculation method based on precise filter medium according to claim 1 is characterized in that: In step S1, the filter screen and the laminated sheets with uniform thickness are simplified to a single-layer plate shell, and the particle method is used for simulation, and the perforated filter screen and the laminated sheets are simulated using the wall method.

3. The CFD-DEM coupling calculation method for filters based on precise filter media according to claim 1 is characterized in that: In step S2, the particle method is used to model the flow field, and the wall method is used to establish the flow field and filter medium models respectively.

4. The CFD-DEM coupling calculation method for filters based on precise filter media according to claim 1, characterized in that: In step S3, when establishing the flow field model, a porous medium model is inserted into the filter medium region, and its coverage area and hydraulic performance parameters are the same as those of the filter medium that has not undergone the filtering process.

5. The CFD-DEM coupling calculation method for filters based on precise filter media according to claim 1, characterized in that: In step S4, the particle method inserts the complete model of the filter medium into the fluid region through the custom particles and the custom inlet.

6. The CFD-DEM coupling calculation method for filters based on precise filter media according to claim 1, characterized in that: In step S4, the wall method inserts the complete model of the filter medium into the fluid region by inserting the wall.

7. The CFD-DEM coupling calculation method for filters based on precise filter media according to claim 1, characterized in that: In step S5, for unidirectional coupling, the distribution and quantity of particles driven by the fluid on the filter medium at the initial stage of filtration are calculated; for bidirectional coupling, the pressure rise during the filtration process and the pattern of filter cake formation are calculated.

8. A filter CFD-DEM coupling calculation system based on precise filter media, characterized in that: include: The analysis module performs an abstract analysis on the filter medium and determines the applicable calculation model; The construction module is used to model the filter without filter media to obtain its flow field, where the use of the wall method requires additional porous media areas to be set in the flow field; The simulation module performs numerical simulation on the filter flow field to obtain its flow state and imports it into the DEM calculation program; A calculation module that models the filter medium and inserts this model into the flow field in the DEM calculation program; The output module performs coupling calculation on the obtained CFD-DEM model to obtain the simulation results of the filter performance.

9. A computer-readable storage medium storing one or more programs, characterized in that: The one or more programs include instructions, which, when executed by a computing device, cause the computing device to perform the method of any one of claims 1 to 7.

10. A computing device, characterized in that include: One or more processors, a memory and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include steps for executing the method according to any one of claims 1 to 7.

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