Particle Penetration through Inclined and L-Shaped Cracks |
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Authors: | Chwen-Jyh Jeng Warren B Kindzierski Daniel W Smith |
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Affiliation: | 1Professor, Toxcon Health Sciences Research Centre Inc., 9607 41 Ave., Edmonton AB, Canada T6E 5X7. E-mail: cjeng@toxcon.com 2Associate Professor, Dept. of Civil and Environmental Engineering, Markin/CNRL Natural Resources Engineering Facility, Univ. of Alberta, Edmonton AB, Canada T6G 2W2 (corresponding author). E-mail: warrenk@ualberta.ca 3Research Scientist, Dept. of Civil and Environmental Engineering, Markin/CNRL Natural Resources Engineering Facility, Univ. of Alberta, Edmonton AB, Canada T6G 2W2. E-mail: dwsmith@ualberta.ca
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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 indicated that inertial impaction and crack entrance cutoff effects were not significant particle deposition mechanisms for the test micron-sized particles. Gravitational sedimentation was the major deposition mechanism. An L-shaped crack can be simulated as the combination of horizontal and vertical sections. This model agreed reasonably with experimental results. |
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Keywords: | Particles Penetration Indoor air pollution Infiltration Cracking |
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