Flow field around circular and non-circular submicron fibers is simulated in this work to study the effects of fiber cross-sectional geometry on its drag force and collection efficiency. In particular, single circular, square, elliptical, and trilobal nanofibers are considered inside computational cells with different solid volume fractions, and their filtration performance are compared their microfiber counterparts. Our results indicate that pressure drop of a fibrous medium is more considerably affected by the fibers' cross-sectional shape if it is made up of nanofibers rather than microfibers. It has been shown that the percentage of pressure reduction due to aerodynamic slip is greater for fibers with streamlined cross-sections. Calculating fiber collection efficiency, it was shown that single fiber efficiency is only weakly influenced by the cross-sectional shape of the fibers in either a slip or no-slip flow regimes. This study is extended to simulate the effects of particle deposition on performance of a submicron circular fiber. For this purpose a novel procedure is developed to model the instantaneous particle loading on a fiber using the Fluent CFD enhanced with in-house subroutines. Our results indicate that the increasing rate of normalized efficiency decreases with increasing loaded mass until it becomes constant, resulting in a linear relationship. The slope of linear part decreases with increasing particle diameter. Fiber drag also increases exponentially with increasing deposited mass with higher rate for smaller particles.
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