Detachment and transport of reavtive-inert agglomerates at different flow velocities in a gas cleaning model filter channel

  • Chair:

    FILTECH 2022, The Filtration Event

  • Place:

    Cologne, Germany

  • Date:

    08.-10.03.2022

  • Author:

    J.R.D. Thieringer, J. Meyer, A. Dittler

  • Particulate filters are a standard component in exhaust aftertreatment systems of vehicles to remove reactive (soot) and inert (ash) particles from the exhaust gas. Wall- flow filters consist of parallel channels with alternately blocked ends. Particles are deposited in the inlet channel, while the gas flows through the porous filter wall into the outlet channel. After reaching a defined pressure drop to remove the reactive components from the filter, the filter is regenerated. During the regeneration, the soot particles are oxidized and the particle layer breaks up. Agglomerates can be detached, transported along the filter channel, and deposited at the end plug of the inlet channel.

    The influence of the particle properties on the resulting deposition patterns and the rearrangement of agglomerates in the particulate filters remain unclear.

    In this study, the rearrangement (detachment, transport and deposition) of agglo- merates without regeneration of the reactive particles in the filter is investigated in order to observe the fundamental processes of detachment and transport of agglomerates in wand flow filters.

    For this purpose, a particle layer of glass spheres, as an ash replacement system, and soot particles is formed in a model filter channel consisting of a single inlet and outlet channel of a particulate filter. The particle layer is exposed to particle-free air at various inlet velocities at ambient temperature. The detachment, as well as the transport of agglomerates from the filter surface, is observed with a high-speed camera over the entire length of the channel. The parameters of agglomerate size and agglomerate velocity are analyzed.

    Even without regeneration of the reactive particles, agglomerates detach and are transported to the end of the filter channel. The velocity of the agglomerates increases after detachment and approaches the gas flow velocity until the agglomerate stops abruptly at the plug of the inlet channel.