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Computational fluid dynamics investigation of human aspiration in low-velocity air: orientation effects on mouth-breathing simulations.

Authors
Anthony-TR; Anderson-KR
Source
Ann Occup Hyg 2013 Jul; 57(6):740-757
NIOSHTIC No.
20043915
Abstract
Computational fluid dynamics was used to investigate particle aspiration efficiency in low-moving air typical of occupational settings (0.1-0.4 m s(-1)). Fluid flow surrounding an inhaling humanoid form and particle trajectories traveling into the mouth were simulated for seven discrete orientations relative to the oncoming wind (0, 15, 30, 60, 90, 135 and 180). Three continuous inhalation velocities (1.81, 4.33, and 12.11 m s(-1)), representing the mean inhalation velocity associated with sinusoidal at-rest, moderate, and heavy breathing (7.5, 20.8, and 50.3 l min(-1), respectively) were simulated. These simulations identified a decrease in aspiration efficiency below the inhalable particulate mass (IPM) criterion of 0.5 for large particles, with no aspiration of particles 100 m and larger for at-rest breathing and no aspiration of particles 116 m for moderate breathing, over all freestream velocities and orientations relative to the wind. For particles smaller than 100 m, orientation-averaged aspiration efficiency exceeded the IPM criterion, with increased aspiration efficiency as freestream velocity decreased. Variability in aspiration efficiencies between velocities was low for small (<22 m) particles, but increased with increasing particle size over the range of conditions studied. Orientation-averaged simulation estimates of aspiration efficiency agree with the linear form of the proposed linear low-velocity inhalable convention through 100 m, based on laboratory studies using human mannequins.
Keywords
Fluids; Hydrodynamics; Aerosols; Air-flow; Particle-aerodynamics; Humans; Analytical-models; Simulation-methods; Mathematical-models; Breathing; Inhalants; Airborne-particles; Author Keywords: aspiration efficiency; CFD inhalability; computational fluid dynamics; continuous inhalation; inhalable particulate mass; mouth breathing; orientation averaged; particle aspiration; particle transport; ultralow velocity
Contact
T. Rene Anthony, Department of Occupational and Environmental Health, University of Iowa, 105 River Street, Iowa City, IA 52242, USA
CODEN
AOHYA3
Publication Date
20130701
Document Type
Journal Article
Email Address
renee-anthony@uiowa.edu
Funding Type
Grant
Fiscal Year
2013
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R01-OH-009290
Issue of Publication
6
ISSN
0003-4878
Source Name
Annals of Occupational Hygiene
State
IA
Performing Organization
University of Iowa
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