Numerical study of the gas–solid flow characteristic of fibrous media based on SEM using CFD–DEM

• The model of the fibrous media is built using Scanning Electron Microscope imaging.
• The effect of structural parameters on separation performance is analyzed by CFD–DEM.
• The influence of particle characteristics on the particle agglomeration is analyzed.
• The influence of structural parameters on particle deposition is considered.

The Computational Fluid Dynamics (CFD)–Discrete Element Method (DEM) coupled method was applied to simulate the gas–solid flow characteristic within the fibrous media, and then to study the influences of the fiber structure and particle properties on particle deposition and agglomeration characteristics in the filtration process. In addition, six fibrous structures with different sizes were designed in this study to analyze the impact of the structural parameters on the filtration performances (including pressure drop and filtration efficiency). The results show that it is convenient and feasible to investigate the fine particle deposition and agglomeration process on the surface of the media using CFD–DEM, and the simulation results are identical with the former experimental observations, numerical simulation and empirical correlation results. In the filtration process, the particles may stack together to form the dendritic structure on the surface of the fibrous media. The pressure drops of all fibrous structures increase relative to those of the gas flow field, and show the trend of the exponential growth. Meanwhile, the total pressure drop of the fibrous media increases with the fiber diameter df, and when df and the length of fibrous media (H) are constant, the pressure drop increases with decreasing the distance that the fiber deviates from the former cross section (L). The pressure drop decreases with the increase of H when df and L keep unchanged; The filtration efficiency decreases with increasing L, and changing H has basically no effect on the filtration efficiency.

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