Spiral double-inlet electrostatic cyclone dust collector and calculation method of multi-field coupling model

Abstract

The invention provides a spiral double-inlet electrostatic cyclone dust collector and a calculation method of a multi-field coupling model, and belongs to the technical field of material preparation equipment. Aiming at the defects of an existing electrostatic cyclone separator (ECP) in the aspects of dust removal efficiency, energy consumption, maintenance cost and structural complexity, the problems existing in the traditional ECP are solved through an optimized spiral double-inlet structure and introduction of an electromagnetic constraint effect on the basis of a mode of combining electrostatic trapping and cyclone separation. By means of the spiral double-inlet design, the trapping efficiency of fine particulate matter (such as PM2.5) is remarkably improved, and the removal efficiency is improved by more than 15% under the condition that the voltage is increased. According to the invention, the dependence on high voltage is reduced, the energy consumption and the operation cost are reduced, high dust removal efficiency is still maintained under low voltage, the electrical insulation requirement and the maintenance burden of equipment are reduced, and the service life of the equipment is prolonged. By simplifying the structural design, economical efficiency and practicability are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of material preparation equipment, and in particular relates to a spiral double-inlet electrostatic cyclone dust collector and a calculation method of a multi-field coupling model. Background Art

[0002] As an important source of electricity production, thermal power generation is widely used around the world. However, the large amount of carbon and fine particulate matter (especially PM2.5) emitted during thermal power generation has become one of the important sources of urban air pollution (Bistline JET, Young DT. The role of natural gas in reaching net-zero emissions in the electric sector. Nature Communications 2022; 13(1)). With increasingly stringent environmental protection standards, how to effectively reduce fine particulate matter emissions generated in thermal power generation has become a technical problem that needs to be solved urgently.

[0003] Electrostatic precipitator is a dust removal device widely used in thermal power plants. It charges particles through a high-voltage electric field and uses the electric field force to attract these particles to the dust collecting electrode, thereby capturing the particles. However, electrostatic precipitators are inefficient in treating ultrafine particles such as PM2.5, and their maintenance is complex and their operating costs are high (Zhu Y, Wei ZD, Yang XY, Tao SL, Zhang YK, Shangguan WF. Comprehensive control of PM 2.5 capture and ozone emission in two-stage electrostatic precipitators. Science of the Total Environment 2023; 858: 159900.). These problems limit their effectiveness in dealing with increasingly stringent emission standards. Therefore, finding more efficient and economical dust removal methods has become the focus of current research.

[0004] A cyclone separator is a device that achieves gas-solid separation based on centrifugal force. It has the advantages of simple structure, strong durability, and easy maintenance. Due to its high efficiency in removing larger particles (such as PM10), cyclone separators are usually used as pretreatment units in dust removal processes (Ren Xiaozhen, Xu Zhichao, Zhao Huan, et al. Exploration of improved design of cyclone dust collector for removing fine particles [J]. Leather Manufacturing and Environmental Technology, 2024, 5(01): 154-156.). However, the removal efficiency of traditional cyclone separators for fine particles is relatively low. Therefore, optimizing the structural design of cyclone separators (such as inlet and outlet structures, cylinder parameters, etc.) to improve their capture efficiency of fine particles is a current research direction.

[0005] In order to improve the integration of the dust removal system, researchers combined the cyclone separator with the electrostatic precipitator technology and developed an electrostatic cyclone precipitator (ECP). ECP places a high-voltage electrode at the center of the cyclone separator to form a radially distributed electric field inside the cyclone separator, so that fine particles are charged and accelerated to move toward the collecting electrode under the action of the electric field force, thereby improving the dust removal efficiency (Liu Jiajin. Numerical simulation and experimental study of cyclone electrostatic precipitator [D]. Jiangxi University of Science and Technology, 2022.).

[0006] Although there are some electrostatic cyclone dust collector solutions, they are only used for experimental research and cannot meet industrial needs.

[0007] Son Pham's team at the University of Saskatchewan proposed an air sampler that combines a quad-inlet cyclone separator and a high voltage trap (Pham S, Dinh A. An air sampler with particle filter usinginnovative quad-inletcyclone separator and high voltage trap. Ieee SensorsJournal 2019; 19(22): 10176-86.) to filter particles of a specific size. The design aims to collect 10 µm~ 70 µm range and exclude particles smaller than 10 µm Sum greater than 70 µm The literature optimized the structure of the cyclone separator and high-pressure collector through numerical simulation and experimental research, proving that the system can effectively remove unwanted particles and achieved good results in multiple experiments. However, there is still room for further optimization in the uniformity of the high-pressure part and the structural design of the cyclone separator inlet to improve the overall efficiency and adapt to more practical application scenarios.

[0008] Zhu Zhenxing from Sinopec Research Institute of Petrochemicals proposed a new type of double-cylinder cyclone separator, which reduces resistance by adding a concentric inner cylinder inside the cylinder, moving the inlet to the lower end and inserting a riser. Cold model experiments and numerical simulations show that when the inlet gas velocity is higher than 28 m / s The efficiency of the new design exceeds that of the PV-type high-efficiency cyclone separator and is consistently higher than that of the ring-flow dust collector. The pressure drop is close to that of the ring-flow dust collector, but is about 50% lower than that of the PV-type separator. % (Zhu Zhenxing, Yuan Shiwei, Tian Zhihong, et al. Separation performance and flow field of a new double-cylinder cyclone separator [J / OL]. Acta Petrolei Sinica (Petroleum Processing), 1-13 [2024-09-04].). This design combines the advantages of countercurrent and direct current cyclone separators, overcomes the defects of traditional countercurrent separators, and has lower resistance and higher separation efficiency. However, the long-term stability and adaptability in practical applications still need to be further verified.

[0009] In summary, the electrostatic cyclone dust collector solutions in the prior art have the following problems: (1) The design of the traditional electrostatic cyclone separator (ECP) is not effective in treating fine particulate matter (such as PM2.5). The structure of the traditional ECP usually has limited capture capacity for fine particulate matter, and therefore cannot provide sufficient removal efficiency when dealing with fine particulate matter control in high-emission industrial processes. (2) In order to improve the dust removal efficiency of the traditional ECP, it is usually necessary to increase the operating voltage. However, increasing the voltage not only leads to an increase in energy consumption, but also places higher requirements on the electrical insulation system of the equipment, thereby increasing the difficulty and cost of equipment maintenance. Even if increasing the voltage can improve the removal efficiency, it also brings additional operating expenses and long-term maintenance problems. (3) Existing high-efficiency ECP designs are often complex in structure and have high manufacturing and maintenance costs. These designs require precise processing and installation to ensure the stability and effectiveness of their performance.

[0010] Therefore, there is an urgent need for a more efficient, economical and easy-to-maintain dust removal solution to meet the challenges of fine particulate matter emissions in modern industrial processes. Summary of the invention

[0011] Aiming at the defects of existing electrostatic cyclone separators (ECP) in dust removal efficiency, energy consumption, maintenance cost and structural complexity, the purpose of the present invention is to provide a spiral double-inlet electrostatic cyclone dust collector and a calculation method of a multi-field coupling model, so as to solve the problems existing in traditional ECP by optimizing the inlet structure and introducing magnetic confinement effect.

[0012] The present invention provides a spiral double-inlet electrostatic cyclone dust collector, which has the following characteristics, including: a cyclone separation unit, which is the outer shell of the spiral double-inlet electrostatic cyclone dust collector, including a cylinder and a frustum, the top center of the cylinder is provided with an air outlet, and the bottom of the cylinder is connected to the wider side of the frustum; an air flow control unit, which is two air inlet channels, the air flow control unit is tangent to the radial plane of the cylinder and is connected to the cylinder, the two air flow control units are distributed at both ends of the circumference of the cylinder and are parallel to each other, the two air flow control units are located in different upper and lower planes, and the air flow control unit is used to introduce an air flow containing dust into the cylinder; a high-voltage current unit is arranged at the top of the air outlet, connected with a static electrode which is vertically downward and extends to the central axis position inside the cylinder; a magnetic field generating unit is arranged at the interface plane between the cylinder and the frustum, and is used to generate a magnetic field inside the cylinder; a dust collecting unit is arranged at the bottom of the frustum, and is used to collect and store dust.

[0013] The spiral double-inlet electrostatic cyclone dust collector provided by the present invention may also have the following features: wherein the dust collection unit includes a dust collecting pole and a dust storage device, both of which are arranged at the inner bottom of the truncated cone body, the dust collecting pole is used to collect dust, and the dust storage device stores the dust collected by the dust collecting pole.

[0014] The spiral double-inlet electrostatic cyclone dust collector provided by the present invention may also have the following feature: wherein the cyclone separation unit is grounded and the electric potential is 0.

[0015] The spiral double-inlet electrostatic cyclone dust collector provided by the present invention may also have the following feature: wherein the flow rate and flow rate of the airflow introduced by the airflow control unit are adjustable.

[0016] The present invention provides a calculation method of a multi-field coupling model, which has the following characteristics: when any of the aforementioned spiral double-inlet electrostatic cyclone dust collectors is used, the internal flow field, electromagnetic field and dust particle dynamic field are coupled, and the following steps are included: S10, a static electrode connected to a high-voltage current unit with a voltage of U0 generates positive ions, causing the dust in the airflow to be charged, so that the dust is subjected to an electric field force directed to the inner wall of the cylinder. F ε , F ε = Q p E c ,in, Q p is the particle charge of the dust, E c is the electric field strength at the location of the dust; S20, since the dust is charged, the dust is also affected by the Lorentz force generated by the magnetic field generating unit. F m ,F m = Q p V p B ,in, V p is the speed of the dust, B is the magnetic field strength; S30, the momentum conservation equation of the dust particle dynamics is described as: m p · d pj / dt = F ε + F m + F Dj ,in m p is the particle mass of dust, ν pj The dust particles j The velocity component in the direction, F Dj is the drag force on the dust particles; S40, the mass conservation equation and momentum conservation equation in the flow process of the airflow containing dust in the cyclone separation unit are respectively expressed as: , , in, ρ g is the density of the airflow containing dust, μ is the gas dynamic viscosity coefficient, μ t is the turbulent viscosity coefficient, S j is the generalized source term in the momentum conservation equation, u i and u j represents the velocity component of the airflow on the coordinate axis, x i and x j represents the spatial coordinate component, t Indicates time, P Indicates pressure, i =1, 2, 3 represent x , y , z direction, j =1, 2, 3 represent x , y , z direction.

[0017] The calculation method of the multi-field coupling model provided by the present invention may also have the following characteristics: wherein, in step S10, Q p As a time-dependent function, Q p = Q s + Q diff , Q s = Q sat · t / ( t + τ ), Q s is the space charge, Q diff is the diffusion charge, Q sat is the saturation space charge, t The time for dust to move. τ is the time constant of the interval charge.

[0018] The calculation method of the multi-field coupling model provided by the present invention may also have the following characteristics: in step S40, the flow process of the dust-containing airflow inside the cyclone separation unit is regarded as viscous, steady-state and incompressible gas-solid two-phase turbulence, and the density of the dust-containing airflow is regarded as a constant.

[0019] Functions and Effects of the Invention The present invention is based on a combination of electrostatic capture and cyclonic separation. It improves the removal efficiency of fine particles (such as PM2.5) by optimizing the spiral double inlet structure and introducing the electromagnetic confinement effect. When the airflow containing dust enters the spiral double inlet electrostatic cyclone separator, the airflow enters the cyclone separation unit while rotating. Through the spiral double inlet design, the rotation speed and path of the airflow are optimized, thereby generating a stronger centrifugal force to quickly throw larger particles to the inner wall of the separator. At the same time, the static electrode in the separator applies an electric field through a high-voltage power supply unit, so that the fine particles are charged. The charged fine particles move toward the dust collecting electrode under the action of the electric field, further improving its capture efficiency.

[0020] The magnetic field generating unit generates a magnetic field inside the separator, and the electromagnetic confinement effect makes it easier for charged particles to be captured by the dust collecting electrode during rotation, thereby improving the dust removal efficiency. Finally, the dust is collected by the dust collecting electrode and stored in the dust collection unit, and the purified gas is discharged from the air outlet.

[0021] Through the combination of airflow optimization and electromagnetic effect of the spiral double inlet structure, the present invention can significantly improve the removal efficiency of fine particles by the electrostatic cyclone separator, especially at higher voltage and magnetic induction intensity, the dust removal efficiency can be increased by 25%. % ~35 % .

[0022] First, the spiral double inlet design of the present invention can significantly improve the capture efficiency of fine particles (such as PM2.5). Compared with the traditional ECP, this structural optimization improves the removal efficiency of fine particles by 3. % , and with increasing voltage, the removal efficiency can be increased by more than 15 % ; Secondly, the present invention reduces energy consumption and equipment operating costs by reducing dependence on high voltage. The spiral double-inlet ECP can still maintain a high dust removal efficiency at a lower voltage, thereby reducing the electrical insulation requirements and maintenance burden of the equipment, and effectively working at a higher voltage to extend the service life of the equipment; finally, the present invention reduces the complexity and manufacturing cost of the system by simplifying the structural design, making the device more economical and practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a stereoscopic diagram of a spiral double-inlet electrostatic cyclone dust collector according to an embodiment of the present invention.

[0024] Figure 2 It is a front view of a spiral double-inlet electrostatic cyclone dust collector according to an embodiment of the present invention.

[0025] Figure 3 It is a top view of the spiral double-inlet electrostatic cyclone dust collector according to an embodiment of the present invention.

[0026] Figure 4 It is a three-dimensional perspective view of a spiral double-inlet electrostatic cyclone dust collector according to an embodiment of the present invention.

[0027] Figure 5 It is a schematic diagram of the electrostatic dust removal mechanism of the spiral double-inlet electrostatic cyclone dust collector according to an embodiment of the present invention.

[0028] Figure 6 It is a schematic diagram of important boundary positions and grids in the spiral double-inlet electrostatic cyclone dust collector of an embodiment of the present invention that may seriously affect the accuracy of numerical simulation.

[0029] Figure 7 It is a multi-field coupling calculation model of an embodiment of the present invention.

[0030] Figure 8 It is a grid-independent verification of the spiral double-inlet electrostatic cyclone dust collector in the embodiment of the present invention.

[0031] Fig. 9It is a comparison of the graded efficiency curves of the simulation results of the spiral double-inlet electrostatic cyclone dust collector in the embodiment of the present invention and the experimental results of the reference (Babaoglu NU. The effects of inlet number and positions on the flow pattern and performance of a Stairmand cyclone. Powder Technol 2024; 434:119297.) under the same conditions.

[0032] Fig.10 It is a schematic diagram of the structure of a single-inlet cyclone dust collector and a double-inlet cyclone dust collector under the prior art.

[0033] Fig.11 The spiral double-inlet electrostatic cyclone dust collector of Test Example 1 of the present invention, the single-inlet cyclone dust collector under the prior art, and the double-inlet cyclone dust collector under the prior art are compared in 10 m / s , 0 kV , 0 T Comparison of graded efficiency under working conditions.

[0034] Fig.12 The spiral double-inlet electrostatic cyclone dust collector of the test example 1 of the present invention and the double-inlet cyclone dust collector of the prior art are compared at 30 k V, 40 k V, 50 k V and 60 k Comparison of graded efficiency at V operating voltage.

[0035] Fig.13 It is the graded efficiency variation curve under different working voltages when the spiral double-inlet electrostatic cyclone dust collector of Test Example 2 of the present invention and the double-inlet cyclone dust collector of the prior art are with or without a magnetic field.

[0036] Fig.14 It is the average contribution rate of the working voltage of the spiral double-inlet electrostatic cyclone dust collector in Test Example 2 of the present invention and the double-inlet cyclone dust collector in the prior art to the PM 2.5 classification efficiency. DETAILED DESCRIPTION

[0037] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the following embodiments and the accompanying drawings specifically illustrate a spiral double-inlet electrostatic cyclone dust collector and a calculation method of a multi-field coupling model of the present invention.

[0038] <Example> Figure 1 is a perspective view of a spiral double-inlet electrostatic cyclone dust collector according to an embodiment of the present invention; Figure 2 is a front view of a spiral double-inlet electrostatic cyclone dust collector according to an embodiment of the present invention; Figure 3 is a top view of a spiral double-inlet electrostatic cyclone dust collector according to an embodiment of the present invention; Figure 4 It is a three-dimensional perspective view of a spiral double-inlet electrostatic cyclone dust collector according to an embodiment of the present invention.

[0039] like Figure 1~Figure 4 As shown, this embodiment provides a spiral double-inlet electrostatic cyclone dust collector 100, including a cyclone separation unit 10, an airflow control unit 20, a high-voltage current unit 30, a magnetic field generating unit 40 and a dust collecting unit 50.

[0040] The cyclone separation unit 10 is the outer shell of the spiral double-inlet electrostatic cyclone dust collector 100 , and includes a cylindrical body 11 and a frustum body 12 .

[0041] The top center of the cylinder 11 has an air outlet.

[0042] The wider side of the truncated cone body 12 is connected to the bottom of the cylindrical body 11. The truncated cone body 12 in this embodiment is grounded and has a potential of zero.

[0043] The airflow control unit 20 is two air inlet channels for introducing dust-containing airflow with adjustable flow rate and flow rate. The airflow control unit 20 is tangent to the radial plane of the cylinder 11 and communicates with the cylinder 11. The two airflow control units 20 are distributed at both ends of the circumference of the cylinder 11 and are parallel to each other. The two airflow control units 20 are located in different planes above and below.

[0044] The high-voltage current unit 30 is disposed at the top of the air outlet of the cylinder 11 , and is connected to a static electrode 31 which is vertically downward and extends to the center axis position of the cylinder 11 .

[0045] The magnetic field generating unit 40 is disposed at the interface plane between the cylindrical body 11 and the frustum of the cone 12 , and is used to generate a magnetic field inside the cylindrical body 11 .

[0046] The dust collecting unit 50 includes a dust collecting electrode 51 and a dust storage device 52 .

[0047] The dust collecting electrode 51 is disposed at the inner bottom of the truncated cone body 12 for collecting dust.

[0048] The dust storage device 52 is disposed at the inner bottom of the truncated cone body 12 and is used to store the dust collected by the dust collecting electrode 51 .

[0049] This embodiment also provides a calculation method for a multi-field coupling model. The calculation method for the multi-field coupling model in this embodiment couples the internal flow field, electromagnetic field, and particle dynamic field of the spiral double-inlet electrostatic cyclone dust collector 100 in this embodiment when in use, and specifically includes the following steps: S10, the static electrode 31 connected to the high voltage current unit 30 with a voltage of U0 generates positive ions, causing the dust in the airflow to be charged, so that the dust is subjected to the electric field force directed toward the inner wall of the cylinder 11 F ε , F ε = Q p E c ,in, Q p is the particle charge of the dust, E c is the electric field strength at the location of the dust (V / m ).

[0050] Will Q p As a time-dependent function, Q p = Q s + Q diff , Q s = Q sat · t / ( t + τ ), Q s is the space charge, Q diff is the diffusion charge, Q sat is the saturation space charge (C), t is the dust movement time ( s ), τ is the time constant of the interval charge.

[0051] S20, since the dust is charged, the dust is also subjected to the Lorentz force exerted on it by the magnetic field generated by the magnetic field generating unit 40. F m , F m = Q p V p B ,in, V p is the speed of the dust, B is the magnetic field strength ( T ).

[0052] S30, describes the momentum conservation equation of dust particle dynamics as: m p· d pj / dt = F ε + F m + F Dj ,in m p is the particle mass of dust ( kg ), ν pj The dust particles j direction( j =1, 2, 3 represent x , y , z The velocity component in the direction m / s ), F Dj is the drag force on the dust particles ( N ).

[0053] S40, the flow process of the dust-containing airflow inside the cyclone separation unit 10 is regarded as a viscous, steady-state and incompressible gas-solid two-phase turbulence, and the density of the dust-containing airflow is regarded as a constant. Thus, the mass conservation equation and momentum conservation equation in the flow process of the dust-containing airflow in the cyclone separation unit 10 are respectively expressed as: , , in, ρ g is the density of the airflow containing dust, μ is the gas dynamic viscosity coefficient ( kg · m / s ), μ t is the turbulent viscosity coefficient ( kg · m / s ), S j is the generalized source term in the momentum conservation equation, u i and u j represents the velocity component of the airflow on the coordinate axis, x i and x j represents the spatial coordinate component, t Indicates time, P Indicates pressure, i =1, 2, 3 representx , y , z direction, j =1, 2, 3 represent x , y , z direction.

[0054] This embodiment uses numerical simulation experiments to demonstrate the feasibility of the spiral double-inlet electrostatic cyclone dust collector 100 in the embodiment.

[0055] The flow of the dust-containing airflow in the spiral double-inlet electrostatic cyclone dust collector 100 has the characteristics of strong vortex and strong anisotropic turbulence. Therefore, the Reynolds stress model is used to simulate the flow field therein, and the standard wall function is adopted. The relevant settings of the Reynolds stress model are shown in Table 1 below.

[0056] Table 1 (Settings of Reynolds stress model) In Table 1 above, SIMPLEC is an improved version of SIMPLE algorithm (semi-implicit pressure-velocity coupling method), which is used to solve the coupling problem of pressure and velocity fields; PRESTO (Pressure Staggering Option) is an interpolation method suitable for pressure field discretization; QUICK (Quadratic Upstream Interpolation for Convective Kinetics) is a second-order accurate interpolation method, which is specially used for the discretization of convection terms, turbulent kinetic energy and turbulent dissipation rate; Second Order Upwind is a second-order accurate upwind discretization method, which is suitable for transport equations in turbulence models and Reynolds stress discretization. The Reynolds stress transport equation adopts second-order upwind discretization to capture the Reynolds stress distribution in turbulence.

[0057] In order to accurately and intuitively describe the motion pattern of the airflow containing dust in the electrostatic cyclone, specific boundary conditions must be combined. Figure 5 and Figure 6 As shown, there are three conditions: capture, reflection and escape. Figure 5 Schematic diagram of the electrostatic dust removal mechanism of the spiral double-inlet electrostatic cyclone dust collector according to an embodiment of the present invention; Figure 6 It is a schematic diagram of important boundary positions and grids in the spiral double-inlet electrostatic cyclone dust collector of an embodiment of the present invention that may seriously affect the accuracy of numerical simulation.

[0058] The parameter settings of the motion mode in the spiral double-inlet electrostatic cyclone dust collector 100 are shown in Table 2 below.

[0059] Table 2 (Boundary conditions of line plate ESP) Figure 7 It is a multi-field coupling calculation model of an embodiment of the present invention.

[0060] In view of the multi-field coupling effect of electromagnetic field, fluid field and particle field in ECP, it is necessary to choose a reasonable calculation method in the solution process. GAMBIT software can establish a simplified model of ECP and divide the grid units. Figure 7 As shown, the segmented grid file and UDF program containing the relationship between the above fields are imported into the FLUENT software, and the initial field parameters and iterative calculations are set in the FLUENT software to complete the entire solution process.

[0061] Meshing is a key technology in computational fluid dynamics. Mesh generation involves dividing the computational domain into smaller, non-overlapping elements, and the fineness of the mesh determines the computational accuracy of the numerical simulation results. The number of meshes in ECP is determined by mesh independence. In order to avoid wasting computing resources and ensure computational accuracy, this embodiment selects the spiral double-inlet ECP model for mesh independence verification. Since the model has a complex structure and the possibility of deformation increases during meshing, selecting it in the mesh independence verification can amplify the credibility of the simulation results.

[0062] Figure 8 It is a grid-independent verification of the spiral double-inlet electrostatic cyclone dust collector in the embodiment of the present invention.

[0063] like Figure 6 and Figure 8 As shown in the figure, the important boundary positions that can seriously affect the accuracy of numerical simulation are located at the air inlet and the junction of the inlet and the cylinder. Secondly, the mesh accuracy of the outlet and the dust collecting electrode at the bottom will also have a great impact on the accuracy of numerical simulation. Figure 8 The data comparison results shown in the figure show that when the number of grids is set to 619148, the dust removal efficiency of the spiral double-inlet electrostatic cyclone dust collector no longer changes significantly with the increase in the number of grids. This number of grids not only ensures the high precision requirements of numerical simulation, but also shows significant advantages in resource utilization efficiency and calculation speed. Therefore, based on the above analysis, 619148 grids are selected as the basis for the numerical simulation of the present invention.

[0064] For the numerical simulation work of ECP, reliability verification is crucial. In order to quantify the similarity between reality and simulation, it is necessary to establish verification between the predicted results and experimental data. The ECP model was degraded to match the literature under the existing technology (Babaoglu NU. The effects of inlet number and positions on the flow patternand performance of a Stairmand cyclone. Powder Technol 2024; 434: 119297.), and numerical simulation was carried out under the same operating conditions to obtain simulation results.

[0065] Fig. 9 It is a comparison of the graded efficiency curves of the simulation results of the spiral double-inlet electrostatic cyclone dust collector in the embodiment of the present invention and the experimental results of the reference (Babaoglu NU. The effects of inlet number and positions on the flow pattern and performance of a Stairmand cyclone. Powder Technol 2024; 434:119297.) under the same conditions.

[0066] The classification efficiency of the experimental results in this embodiment is compared with the simulation results. Fig. 9 As shown, in order to ensure the accuracy and reliability of the simulation results and verify their consistency with the actual working conditions, this embodiment designs a strict simulation-experimental result comparison and verification process. First, the self-built spiral double-inlet electrostatic cyclone dust collector model was finely degraded to make it strictly correspond to the electrostatic cyclone dust collector model described in the experiment of the reference (Babaoglu NU. The effects of inlet number and positions on the flow pattern and performance of a Stairmandcyclone. Powder Technol 2024; 434: 119297.) in terms of key parameters and structure. Subsequently, under the premise of keeping the operating conditions consistent, the two models (the self-built spiral double-inlet electrostatic cyclone dust collector model and the electrostatic cyclone dust collector model described in the reference) were carefully numerically calculated, focusing on the comparative analysis of the classification efficiency as shown in the figure. Fig. 9 shown.

[0067] The physical characteristics of the dust particles in this example are shown in Table 3 below.

[0068] Table 3 (Physical characteristics of dust particles) <Test Example 1> This test example tests the effect of structural changes of the airflow control unit 20 in the embodiment and the voltage of the high-voltage current unit 30 on the dust removal efficiency of the spiral double-inlet electrostatic cyclone dust collector 100.

[0069] Fig.10 It is a schematic diagram of the structure of a single-inlet cyclone dust collector and a double-inlet cyclone dust collector under the prior art.

[0070] like Fig.10 As shown, the single-inlet cyclone dust collector 101 in the prior art contains only one airflow control unit 20; the double-inlet cyclone dust collector 102 in the prior art contains two airflow control units 20, but the two airflow control units 20 are located in the same plane and guide the airflow into the same plane inside the cylinder 11.

[0071] There are many factors that affect the ECP collection efficiency. As the working conditions change, the dust removal efficiency will also change accordingly. Therefore, dust removal efficiency is an important indicator for evaluating the performance of dust collectors. Classification efficiency refers to the dust removal efficiency at a certain particle size, and its formula is as follows: η g =( c 0 k - c 1 k ) / c 0 k in, c 0 k Indicates that at the entrance k The average mass concentration of the particle size ( kg / m 3 ), c 1 k Indicates that at the exit k The average mass concentration of the particle size ( kg / m 3 ), η g represents the fractionation efficiency ( % ).

[0072] The test of the improvement effect of the air inlet structure (airflow control unit) of the cyclone dust collector requires shielding against the influence of electric and magnetic fields.

[0073] Fig.11 The spiral double-inlet electrostatic cyclone dust collector of Test Example 1 of the present invention, the single-inlet cyclone dust collector under the prior art, and the double-inlet cyclone dust collector under the prior art are compared in 10 m / s , 0 kV , 0 T Comparison of graded efficiency under working conditions.

[0074] like Fig.11 As shown, the following conclusions can be drawn: (1) The dust removal performance of the three ECPs increases with the increase of particle size, which also reveals the weakness of ECP in collecting fine particles, especially submicron particles.

[0075] (2) Compared with the traditional cyclone dust collector, the dust collection performance of the spiral double-inlet electrostatic cyclone dust collector is improved by nearly 3.0 compared with the dust collection performance of the single-inlet cyclone dust collector under the existing technology. % It can be concluded that the changes to the conventional air intake structure in this embodiment have achieved significant results.

[0076] (3) For double-inlet ECPs, the difference in classification efficiency between the spiral double-inlet electrostatic cyclone dust collector and the double-inlet cyclone dust collector under the existing technology is 1.0 % In the absence of electric and magnetic fields, the dust removal performance of the double-inlet cyclone dust collector in the prior art is better than that of the spiral double-inlet electrostatic cyclone dust collector in the embodiment.

[0077] Fig.12 The spiral double-inlet electrostatic cyclone dust collector of the test example 1 of the present invention and the double-inlet cyclone dust collector of the prior art are compared at 30 k V, 40 k V, 50 k V and 60 k Comparison of graded efficiency at V operating voltage.

[0078] The voltage range of the corona wire (static electrode) in traditional electrostatic cyclone dust collector is generally 30 k V~60 k V, such as Fig.12 As shown, respectively, at 30 k V, 40 k V, 50 k V and 60 k The classification efficiency of the spiral double-inlet electrostatic cyclone dust collector (STI) of the embodiment of the present invention and the double-inlet cyclone dust collector (TI) of the prior art was tested at a working voltage of V. Fig.12 The following conclusions can be drawn: (1) With the increase of working voltage, the classification efficiency of the two ECPs gradually improves, and the increase of PM2.5 is enhanced, especially the increase of PM1.

[0079] (2) For dual-inlet ECPs at the same operating voltage, the classification efficiency of the spiral type (spiral dual-inlet electrostatic cyclone dust collector) is generally higher than that of the horizontal type (dual-inlet cyclone dust collector under the existing technology). This trend is more obvious in the submicron particle range, with the maximum increase of up to 4.0 % .

[0080] (3) The effect of voltage change on the spiral double-inlet electrostatic cyclone dust collector is significantly smaller than that on the double-inlet cyclone dust collector under the prior art, indicating that the spiral double-inlet electrostatic cyclone dust collector has better stability in this high voltage range. This feature is conducive to the practical industrial application of the spiral double-inlet electrostatic cyclone dust collector.

[0081] (4) Improving the existing double-inlet cyclone dust collector structure to a spiral type (spiral double-inlet electrostatic cyclone dust collector) can reduce the required high pressure value while still achieving the same dust removal effect.

[0082] In this test example, in order to more clearly illustrate the impact of voltage change on the improvement of classification efficiency, the average contribution rate is introduced. Fig.12 From the data, we can see that with 30 k The average contribution rate based on V data is the average difference between the graded efficiency and the base voltage at each operating voltage, which is given by Fig.12 The following conclusions can be drawn: (1) Under the same voltage, the average voltage contribution rate of the double-inlet cyclone dust collector under the prior art is higher than that of the spiral double-inlet electrostatic cyclone dust collector, which also means that the double-inlet cyclone dust collector under the prior art is more sensitive to voltage changes.

[0083] (2) The increase in voltage leads to an increase in the average voltage contribution rate, but the magnitude of the increase will decrease, which is reflected in both types of cyclone dust collectors in this test example.

[0084] (3) In 30 k V-60 k Within the V range, each increase of 10 k V, the average relative contribution rate increased by 3.9 % , corresponding to 40 k V operating voltage, which provides a feasible method for determining the optimal operating voltage in industrial applications.

[0085] <Test Example 2> This test example is based on test example 1, and tests the influence of the magnetic confinement effect generated by the magnetic field generating unit 40 in the embodiment on the dust removal efficiency of the spiral double-inlet electrostatic cyclone dust collector 100.

[0086] According to the influence of working voltage on the double inlet cyclone dust collector under the existing technology, 30 k V and 40 k V is used as a suitable voltage value to study the magnetic confinement effect. T The representative magnetic induction intensity is particularly valuable in practical industrial applications.

[0087] Fig.13 It is the graded efficiency variation curve under different working voltages when the spiral double-inlet electrostatic cyclone dust collector of Test Example 2 of the present invention and the double-inlet cyclone dust collector of the prior art are with or without a magnetic field.

[0088] like Fig.13 As shown, the following conclusions can be drawn: (1)0.25 T The introduction of magnetic field improves the classification efficiency of spiral double-inlet electrostatic cyclone (STI) and double-inlet cyclone (TI) under the existing technology, especially the classification efficiency of submicron particles is improved by more than 2.0 % .

[0089] (2) The increase in voltage will weaken the enhancement of the classification efficiency by magnetic induction intensity. Under high voltage conditions, the magnetic field introduced into the spiral double-inlet electrostatic cyclone dust collector has a more significant improvement than the magnetic field introduced into the double-inlet cyclone dust collector under the prior art.

[0090] Depend on Fig.13 The data shows that the average contribution rate is 0.25 T The average difference between the classification efficiency under magnetic field and the classification efficiency without magnetic field.

[0091] Fig.14 It is the average contribution rate of the working voltage of the spiral double-inlet electrostatic cyclone dust collector in Test Example 2 of the present invention and the double-inlet cyclone dust collector in the prior art to the PM 2.5 classification efficiency.

[0092] like Fig.14 As shown, the following conclusions can be drawn: (1) Under the same voltage, the average voltage contribution rate of the double-inlet electrostatic cyclone dust collector is higher than that of the spiral double-inlet electrostatic cyclone dust collector, which also means that the double-inlet electrostatic cyclone dust collector is more sensitive to voltage changes.

[0093] (2) The increase in voltage leads to an increase in the average contribution rate, but the magnitude of the increase decreases, which is reflected in the two types of electrostatic cyclone dust collectors.

[0094] Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A spiral double-inlet electrostatic cyclone dust collector, characterized in that: include: The cyclone separation unit is the outer shell of the spiral double-inlet electrostatic cyclone dust collector, comprising a cylindrical body and a frustum body, wherein the top center of the cylindrical body has an air outlet, and the bottom of the cylindrical body is connected to a wider side of the frustum body; An air flow control unit, which is two air inlet channels, wherein the air flow control unit is tangent to the radial plane of the cylinder and is connected to the cylinder, the two air flow control units are distributed at both ends of the circumference of the cylinder and are parallel to each other, and the two air flow control units are located in different upper and lower planes, and the air flow control unit is used to introduce air flow containing dust into the cylinder; A high-voltage current unit is arranged at the top of the air outlet and is connected to a static electrode which is vertically downward and extends to the center axis of the cylinder; A magnetic field generating unit is arranged at the interface plane between the cylindrical body and the truncated cone body, and is used to generate a magnetic field inside the cylindrical body; The dust collecting unit is arranged at the bottom of the truncated cone and is used for collecting and storing the dust.

2. The spiral double-inlet electrostatic cyclone dust collector according to claim 1 is characterized in that: in, The dust collection unit includes a dust collecting electrode and a dust storage device, both of which are arranged at the inner bottom of the truncated cone. The dust collecting electrode is used to collect the dust, and the dust storage device stores the dust collected by the dust collecting electrode.

3. The spiral double-inlet electrostatic cyclone dust collector according to claim 1 is characterized in that: in, The cyclone separation unit is grounded and has a potential of 0.

4. The spiral double-inlet electrostatic cyclone dust collector according to claim 1 is characterized in that: in, The flow rate and flow rate of the airflow introduced by the airflow control unit are adjustable.

5. A calculation method for a multi-field coupling model, characterized in that: The method of coupling the internal flow field, electromagnetic field and the particle dynamic field of the dust of the spiral double-inlet electrostatic cyclone dust collector as claimed in any one of claims 1 to 4 when in use comprises the following steps: S10, the static electrode connected to the high voltage current unit with a voltage of U0 generates positive ions, causing the dust in the airflow to be charged, so that the dust is subjected to an electric field force directed toward the inner wall of the cylinder. F ε , F ε = Q p E c ,in, Q p is the particle charge of the dust, E c is the electric field strength at the location of the dust; S20, since the dust is charged, the dust is also subjected to the Lorentz force exerted on it by the magnetic field generated by the magnetic field generating unit F m , F m = Q p V p B ,in, V p is the velocity of the dust, B is the magnetic field strength; S30, describing the momentum conservation equation of the dust particle dynamics as: m p · d pj / dt = F ε + F m + F Dj ,in m p is the particle mass of the dust, ν pj The dust particles are j The velocity component in the direction, F Dj is the drag force on the dust particles; S40, expressing the mass conservation equation and momentum conservation equation during the flow of the airflow containing the dust in the cyclone separation unit as follows: ， ， in, ρ g is the density of the airflow containing the dust, μ is the gas dynamic viscosity coefficient, μ t is the turbulent viscosity coefficient, S j is the generalized source term in the momentum conservation equation, u i and u j represents the velocity component of the airflow on the coordinate axis, x i and x j represents the spatial coordinate component, t Indicates time, P Indicates pressure, i =1, 2, 3 represent x , y , z direction, j =1, 2, 3 represent x , y , z direction.

6. The calculation method of the multi-field coupling model according to claim 5, characterized in that: in, In step S10, Q p As a time-dependent function, Q p = Q s + Q diff , Q s = Q sat · t / ( t + τ ), Q s is the space charge, Q diff is the diffusion charge, Q sat is the saturation space charge, t is the dust movement time, τ is the time constant of the interval charge.

7. The calculation method of the multi-field coupling model according to claim 5, characterized in that: in, In step S40, the flow process of the airflow containing the dust inside the cyclone separation unit is regarded as a viscous, steady-state and incompressible gas-solid two-phase turbulent flow. The density of the air flow containing the dust is considered to be constant.

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