CFD-DEM Modeling of Particle Deposition on Single Filter Fiber: Evidence of Particle Mobility after Deposition

The present study investigates the particle deposition process on a single filter fiber under continuous loading conditions. An effective, partially decoupled CFD-DEM simulation approach is employed, which will subsequently allow the simulation of continuous particle deposition on larger, more realistic fiber structures or multi-layer fibrous filter media. Accuracy of the approach is demonstrated by comparison with unsteady full-coupled CFD-DEM simulations. DEM parameters for the employed JKR Model were taken from literature, even though macroscopic calibration experiments were also performed. Different process conditions based on the classification by Kasper at al. J. Aerosol Sci., 2010) were investigated, leading (in experimental investigations) to different deposition morphologies on a singular fiber, i.e., dendritic structures in the upstream direction, compact upstream facing particle deposits, and lobe-type deposits of particles. Simulations show that deposition morphology is not only a result of initial particle deposition or its deposition upon initial bounce back, as suggested by previous works. More importantly, it is due to the repositioning of deposited particles or particle agglomerates as a consequence of acting aerodynamic forces and particle impulse transfer on the deposited particle structures. Experimental evidence of the prescribed repositioning of particles obtained from high speed videography is presented.