Model-based performance analysis of pleated filters with non-woven layers

The water flow rates of commercial sterilizing grade 10 '' filter cartridges were simulated by Computational Fluid Dynamics (CFD) and compared to experimental data. This study compares four methods used to reconstruct the internal pleat geometry ranging from generic designs to analysis of microscopic images. The impact of the cartridges' plastic cage on flow resistance was studied and found to be negligible. A systematic overestimation of the simulated filter flow rate was attributed to additional hydrodynamic resistance of the non-woven material between the pleats. The permeability of the non-woven material was estimated by fitting CFD models to experimentally determined water flow rates and compared to the permeability of this material as directly measured with a flow cell. Good correlation between CFD-based estimations and directly measured values was found at low pressures, while differences at high pressures indicated the existence of further flow resistance, which is hypothesized to be caused by deformation of the pleat geometry under pressure.