Particle Penetration through Inclined and L-Shaped Cracks

Abstract

This paper presents a particle penetration model predicting particle penetration coefficient ( Pp ) through a narrow crack of arbitrary incline angles (θ) . The objective was to simulate Pp for outdoor-to-indoor particle penetration for residential infiltration conditions. This model assumes laminar infiltration flow and considers particle deposition from both gravitational sedimentation and Brownian diffusion. For micron-sized particles, modeling results indicate that gravitational sedimentation is the major deposition mechanism. Pp increases monotonically with ∣θ∣ because effective particle sedimentation velocity ( vs cos θ) decreases monotonically with ∣θ∣ . For submicron-sized particles (0.1 μm) , Brownian diffusion is the major particle deposition mechanism. Because Brownian diffusion is a nondirectional deposition mechanism, crack inclination did not affect Pp . This study applied this model to estimate Pp for L -shaped cracks, and validated modeling results with experiments. Experimental results in...