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CN-122021025-A - Macroscopic numerical simulation and verification method for dust deposition uniformity of metal filter bag dust collector

CN122021025ACN 122021025 ACN122021025 ACN 122021025ACN-122021025-A

Abstract

The invention relates to the technical field of industrial dust removing equipment design and fluid simulation, and discloses a macroscopic numerical simulation and verification method for dust deposition uniformity of a metal filter bag dust remover, which comprises the steps of constructing a full-size model of the dust remover loaded with a porous jump medium boundary; establishing an Euler-Lagrange gas-solid coupling model to calculate flow field and particle track, designing a flow guiding structure orthogonal experiment based on flow field characteristics to obtain running resistance and deposition quality data under different parameter combinations, establishing an evaluation system comprising flow distribution coefficients and deposition uniformity indexes to screen an optimal structure, constructing a physical experiment platform to carry out powder coating and sectional scraping weighing, and verifying the reliability of a method through relative errors of comparison experiment and simulation data. According to the invention, through macroscopic equivalent modeling and quantitative evaluation, accurate prediction of the internal deposition behavior of the metal filter bag dust collector is realized, the problem of uneven load of the filter bag is effectively solved, and a reliable basis is provided for structure optimization.

Inventors

  • YE HAOWEN

Assignees

  • 西南科技大学

Dates

Publication Date
20260512
Application Date
20260130

Claims (10)

  1. 1. The macroscopic numerical simulation and verification method for the dust deposition uniformity of the metal filter bag dust collector is characterized by comprising the following steps of: s1, constructing a full-size geometric model of a metal filter bag dust collector, and defining the side wall surface of the metal filter bag as an inner boundary for loading porous jumping medium boundary conditions; S2, establishing an Euler-Lagrangian gas-solid two-phase bidirectional coupling model, and obtaining an initial flow field and a particle motion track in the dust remover through numerical calculation; S3, designing a diversion structure scheme and carrying out orthogonal experimental simulation of structural parameters based on the calculation result of the S2 to obtain flow field distribution data, running resistance and filter bag surface deposition quality data under different parameter combinations; s4, calculating a flow distribution coefficient, a speed relative mean square error and a deposition uniformity index according to the data obtained in the S3, screening an optimal structural parameter combination by taking the flow distribution coefficient, the speed relative mean square error and the deposition uniformity index as evaluation indexes, and evaluating the flow field distribution state and the uniformity degree of particle deposition on the surface of the filter bag; And S5, carrying out powder coating experiments by using a physical experiment platform of the metal filter bag dust collector, acquiring experimental running resistance, acquiring surface deposition quality data of the experimental filter bag by a physical scraping method after the experiment is finished, and verifying the reliability of the numerical simulation method by comparing the relative errors of the experimental data and the numerical simulation data in S3.
  2. 2. The method for macroscopic numerical simulation and verification of dust deposition uniformity of a metal filter bag collector according to claim 1, further comprising a discretization step before performing the numerical calculation in step S1: Discretizing the computational fluid domain space by adopting an unstructured grid algorithm, and implementing a multi-scale local encryption strategy; Constructing boundary layer grids on the inner wall surface of the dust collector box body and the outer surface of the metal filter bag; and establishing a grid independence judgment standard taking the pressure drop of the whole system as a target variable, and determining the number of grids meeting the calculation precision by monitoring the pressure drop change.
  3. 3. The macroscopic numerical simulation and verification method of dust deposition uniformity of a metal filter bag dust collector according to claim 1, wherein in step S2, the establishing the euler-lagrangian gas-solid two-phase bidirectional coupling model specifically comprises: establishing a gas phase conservation model based on a fluid continuity hypothesis and a Navier-Stokes law, and solving a turbulence equation by adopting a turbulence model; Establishing a particle dynamics model based on Newton's second law and angular momentum conservation law; and by adding a momentum source term in the gas phase momentum equation, the bidirectional coupling feedback of the particles relative to the gas phase flow field is realized.
  4. 4. The macroscopic numerical simulation and verification method of dust deposition uniformity of a metal filter bag dust collector according to claim 1, wherein in S1, the loading method of the porous jump medium boundary condition is as follows: And carrying out macroscopic equivalent treatment on the metal filter bag by adopting a porous jump medium model, and describing the pressure loss of the air flow passing through the metal filter bag by using Darcy's law and an inertia loss term, wherein the pressure loss is related to hydrodynamic viscosity, permeability, pressure step coefficient and effective thickness.
  5. 5. The method for macroscopic numerical simulation and verification of dust deposition uniformity of a metal filter bag collector according to claim 1, wherein in S2, the numerical calculation is preceded by a boundary condition setting step: Setting an air inlet of the dust remover as a speed inlet boundary, and setting an air outlet as a pressure outlet boundary; the sections of the air inlet and the air outlet of the dust remover are set as escape boundaries, the outer surface of the porous medium of the metal filter bag is set as a capturing boundary, and the wall surface of the dust remover box body, the inner wall of the ash bucket and the surface of the flow guiding structure are set as reflection boundaries.
  6. 6. The macroscopic numerical simulation and verification method for dust deposition uniformity of a metal filter bag dust collector according to claim 1, wherein in S3, the flow guiding structure scheme adopts a porous spoiler assembly, and the structural parameters selected by the orthogonal experimental simulation include hole area occupation ratio, spoiler spacing and hole pattern; In S4, screening the optimal structural parameter combination specifically comprises the steps of calculating the deviation square sum and the influence degree of each structural parameter on the evaluation index by adopting an analysis of variance method, and determining the optimal level of each parameter.
  7. 7. The macroscopic numerical simulation and verification method of dust deposition uniformity of a metal filter bag dust collector according to claim 1, wherein in S4, the flow distribution coefficient calculating method is as follows: Selecting the outer surface of a cylindrical porous medium of the metal filter bag as a monitoring surface, and obtaining the actual treatment air quantity of a single metal filter bag by carrying out surface area separation on a normal speed vector on the monitoring surface; And calculating the ratio of the actual treatment air quantity of the single metal filter bag to the average treatment air quantity of all the metal filter bags.
  8. 8. The macroscopic numerical simulation and verification method of dust deposition uniformity of a metal filter bag dust collector according to claim 1, wherein in S4, the calculation method of the deposition uniformity index is: Dividing the metal filter bag into a plurality of equidistant characteristic areas along the vertical height direction by adopting an axial segmentation sampling method in a numerical model; Counting the deposition amount of particles captured by the wall surface in each characteristic area; And calculating the relative average deviation of the particle deposition amounts of all the characteristic areas relative to the average deposition amount, and calculating a deposition uniformity index based on the relative average deviation.
  9. 9. The macroscopic numerical simulation and verification method of dust deposition uniformity of a metal filter bag collector according to claim 1, wherein in S5, the powder coating experiment performed by using the physical experiment platform of the metal filter bag collector specifically comprises: constructing a full-size experiment platform integrating an air source system, a dust removing system and a filtering system, and configuring an anemometer for monitoring flow speed, a laser particle size analyzer for analyzing particle size distribution and a differential pressure transmitter for recording pressure drop of the system; Configuring experimental materials to ensure that the particle size distribution of the materials adopted in the powder coating experiment is consistent with the particle size distribution set in the S2 numerical simulation; The particle size distribution of the materials adopted in the powder coating experiment is consistent with the setting in the numerical simulation.
  10. 10. The macroscopic numerical simulation and verification method of dust deposition uniformity of a metal filter bag dust collector according to claim 1, wherein in S5, collecting experimental filter bag surface deposition quality data by a physical scraping method specifically comprises: after the powder coating experiment is finished, stripping the powder deposited on the surface of the filter material from top to bottom along the axial direction of the metal filter bag in a physical scraping mode; Carrying out partition collection and respective weighing on the stripped powder according to the height of the metal filter bag to obtain actual measurement values of the deposition quality of each region; The specific calculation mode of the relative error is that the absolute value of the difference between the actual measurement value of the deposition quality and the deposition quality data of the surface of the corresponding numerical simulation filter bag in the step S3 is calculated and divided by the actual measurement value of the deposition quality.

Description

Macroscopic numerical simulation and verification method for dust deposition uniformity of metal filter bag dust collector Technical Field The invention relates to the technical field of industrial dust removal equipment design and fluid simulation, in particular to a macroscopic numerical simulation and verification method for dust deposition uniformity of a metal filter bag dust remover. Background The metal filter bag dust collector is widely applied to dust-containing gas purification systems in the industries of metallurgy, chemical industry, energy sources and the like by virtue of the characteristics of high temperature resistance, corrosion resistance, high mechanical strength and the like. In actual operation, the distribution characteristics of the flow field inside the dust remover directly determine the dust deposition form on the surface of the filter bag and the operation stability of the device. Because of the influence of the structural space and the air inlet mode of the dust remover box body, the air flow is influenced by inertia effect to easily form a high-speed jet flow or vortex area after entering the box body, so that the flow distribution difference among filter bag arrays is larger. Such flow field non-uniformity can cause the filter bag adjacent to the air inlet or local feature area to bear excessive filtering load, and dust is rapidly accumulated on the surface of the filter bag to form a high ash blocking cake layer, so that local running resistance is rapidly increased. Meanwhile, the scouring of high-speed dust-containing air flow can accelerate the abrasion of metal filter materials, and the effect of pulse ash removal can be weakened due to the fact that local deposition is too thick, the phenomenon of incomplete ash removal is caused, the service life of the filter bag is shortened, and the maintenance cost is increased. Therefore, optimizing the flow guiding structure to promote the uniformity of flow field and deposition distribution is a key link of the design of the dust remover. Currently, computational Fluid Dynamics (CFD) has become the dominant means of analyzing the internal flow fields of dust collectors, but there are still limitations in the application of metal filter bag collectors. On one hand, the filtering materials such as metal fiber felt and the like have complex micro-pore structures, if a full-size microscopic model is directly established, the number of calculation grids is large, the calculation resource consumption is overlarge, the popularization in engineering design is difficult, and if only a single porous medium model is adopted, the coupling effect of gas-solid two phases on the surface of a filter bag and the non-uniform deposition behavior of particles are difficult to accurately represent. On the other hand, the existing structural optimization design is mainly based on flow field velocity vectors or total pressure drop indexes for qualitative analysis, and a quantitative evaluation system aiming at dust deposition uniformity is lacked, so that the design of the flow guiding device is excessively dependent on experience, and the optimal effect is difficult to achieve. In addition, in the verification link of numerical simulation, the prior art generally only compares the total pressure drop of an inlet and an outlet of a system, and cannot check the actual distribution condition of dust deposition quality on the surfaces of filter bags in different areas inside the dust remover, so that the guidance precision of simulation results on actual engineering is limited. Therefore, it is necessary to establish a macroscopic numerical simulation method that combines both computational efficiency and accuracy, and includes quantitative evaluation and closed-loop verification of physical experiments. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a macroscopic numerical simulation and verification method for dust deposition uniformity of a metal filter bag dust collector, which solves the problems that in the design process of the existing metal filter bag dust collector, an accurate prediction means for the coupling relation between the dust microscopic deposition behavior and macroscopic flow field distribution is lacking, and the quantitative optimization design of a flow guiding structure is difficult, so that the flow distribution of a filter bag array is uneven, the local deposition load is too high and the ash cleaning period is shortened. In order to solve the problems, the invention provides the following technical scheme: The invention provides a macroscopic numerical simulation and verification method for dust deposition uniformity of a metal filter bag dust collector, which comprises the steps of building a full-size geometric model, building a gas-solid two-phase flow coupling calculation model, designing a diversion structure orthogonal experiment, multi-dimensional evaluation index analysis and