Permeability modeling of fibrous media with bimodal fiber size distribution

Fibrous media as aerosol filtration devices are widely used in many industrial applications and present a wide variety of features like the fiber composition, the solid volume fraction, the fiber diameter distribution and the fiber orientation. Among them are nonwovens materials, which are mostly composed of fibers blends. The two main characteristics of these filters are the filtration efficiency and the pressure drop. These properties depend on the filter thickness, the face velocity, the fluid viscosity, etc. Recently, predictive expressions for bimodal media have been developed based on the combination of unimodal equivalent radius models and dimensionless permeability. The main contribution of this work is to propose combinations for a wide range of realistic fibrous filters in addition to experimental validation. The building of a universal model to predict the permeability of bimodal fibrous media for a wide range of solid volume fraction, αα and fiber diameter ratio, R   is envisaged. Therefore our approach has been to test different analytical correlations for 0.05<α<0.20.05<α<0.2 and 2

Graphical summary of preferential models areas according to solid volume fraction and diameter ratio. The dark gray area corresponds to the dimensionless permeability model given by Davies (1952), the light gray area corresponds to the Jackson and James (1986) model. The lined area corresponds to the unimodal equivalent radius from Tafreshi et al. (2009), the lined/dotted area corresponds to the Brown and Thorpe (2001) radius.Figure optionsDownload high-quality image (204 K)Download as PowerPoint slideHighlights
► Permeability models of media with bimodal fiber size distribution are discussed.
► Structures generation with flow computation were performed for 0.05<α<0.150.05<α<0.15, 2► Experimental measurements allow to obtain good agreement with simulated values. We proposed preferential models area according to αα and R.