Prediction of filtration performance of compressed fibrous media

Abstract

Fibrous filter media is usually subjected to compression in practice. However, the effect of compression on the pore structure, flow field and filtration performance of heterogeneous compressed filter media has not been studied well. In this work, the filtration performance of two fibrous filter media with different compressions was investigated by experiments, classical single fiber efficiency theory and simulations. Artificial 3-D structures were established via GeoDict software based on the parameters of real uncompressed fibrous filter media. There was good agreement between the experimental and simulated results. For compressed filter media, it was found that the equivalent fiber diameter increased with increasing compression ratio. After compression, a shift in the pore size distribution and an increase in the channel tortuosity can be observed. The filtration performance varies for different compressed filter media. In addition, the filtration efficiency decreases as the angle between the fibers and the X-Y plane increases. There is a decrease in the penetration for structures with a broader fiber size distribution. Not only the real fiber size distribution and orientation but also the variation in fiber diameters with compression should be considered when predicting or calculating the performance of compressed filter media.