In situ characterization of particle structures generated at different flow velocities on a single fiber in the gas phase

  • Author:

    J. Szabadi, J. Meyer, A. Dittler

  • Source:

    Journal of Aerosol Science, 2023, 106197,

  • For the design of a gas-cleaning filter, the morphology of particle deposits on filter fibers is of significant interest. In this study, particle structures were generated with polydisperse particulate material and mainly deposited by diffusion or by interception and inertia. The structures were characterized in situ with structures generated by monodisperse material known from literature. A quantitative comparison showed that the particle structures of polydisperse material are comparable to those of monodisperse material. It was demonstrated that only an in situ investigation provided artifact-free results for very dendritic particle structures of Carbon Black. At a Péclet number of Pe = 1.67-104, the dendrites are arranged uniformly around the fiber at an angle of 90° and folded down in the direction of the gravity field after the inflow was turned off. The particle structures of Carbon Black at higher Péclet numbers (2.6∙105-1∙106) are less dendritic and showed no visual change when the flow was switched off. However, they were not stable enough to be removed and further examined by laser scanning microscopy in addition to in situ observation. Only the particle structures made of glass spheres are stable enough and could be removed for further investigation.