| Air pollution is quite serious in China today due to high total particle pollution exhaust emission level, As the requirements for air pollution control are becoming increasingly strict, there is a constant demand for more effective pollution control technologies. Bag fliter is a kind of high-efficiency dust collect equipment. In the present work, several numerical simulations of issues related to the technology of particle collection were conducted to investigate the gas flow distribution and filbration dust theory on baghouse, which is of great importance for the optimizing structure design of bag filter. The major focuses and research findings of this paper are as follows:(1) Flow characteristics and performance of large-scale bag filter were simulated using Ansys Fluent software. In the simulation, the distribution data of airflow velocity and pressure in the dust collector were been obtained. The paper compared air distribution law in different locations inside the dust collector through the the analysis of gas flow velocity on each bag. The simulation results were compared with experimental data, which show good agreement from each other. The simulation results can provide design data for the configuration parameter of gas flow distribution devices in bag filter.(2) The gas-solid two phase flow through the bag filter fibers was numerically simulated by Lattice Boltzmann Method. The one-way coupled technique was used to describe the particles’ movement behavior according to the Lagrange method. The results indicate that the variation of pressure drop conforms to the Darcy’s law perfectly when gas flow passes through the porous media. The principles of the particulate (diameter≤1μm) transportation and deposition on to the surfaces of the bag fiber were also discussed. The simulation results have shown that the collection efficiency varies with the particle diameter. When the particle diameter is less than0.01μm, the collection efficiency is quite high due to the strong Brownian diffusion effect. If the particle is greater than0.1μm, the collection efficiency goes up too, since the interception mechanism of the fiber plays an important role for the big size particles. However, it is relatively difficult to trap the particles in the range from0.01μm to0.1μm. The simulation is meaningful for the mechanism researches of bag-type dedust.(3) A numerical simulation model on bag filter was established to simulate the performance of dust dislodgement with pulse-jet. In the simulation, the parameters of model were set as flows:pulse-jet pressure was0.4MPa、pulse-jet time was100ms、the distance of pulse-jet was200mm、the diameter of filter bag was150mm、and the length of filter bag was6000mm. The unsteady flow mathematic model were adopted to compute the inside flow of single filter bag when it was cleaning by pulse-jet. Realizable k-ε model was employed to describe the turbulent flow. The results of simulation calculation could show the magnitude of peak pressure at differents time and distribution of that along the length of filter bag. The pressure data of CFD simulation were imported into the finite element analysis software Ansys Workbench for the transient kinetic analysis based on Fluid-Solid-Coupling. The paper simulated the movement of bag filter under the pulse-jet pressure, got the acceleration vary with the simulation time. The acceleration values of the filter bag can be used as an important indicator of the evaluation for the cleaning efficiency of the baghouse pulse-jet device. |
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