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

Authors
Anderson-KR; Anthony-TR
Source
Ann Occup Hyg 2014 Jun; 58(5):625-645
NIOSHTIC No.
20044518
Abstract
An understanding of how particles are inhaled into the human nose is important for developing samplers that measure biologically relevant estimates of exposure in the workplace. While previous computational mouth-breathing investigations of particle aspiration have been conducted in slow moving air, nose breathing still required exploration. Computational fluid dynamics was used to estimate nasal aspiration efficiency for an inhaling humanoid form in low velocity wind speeds (0.1-0.4 m s-1). Breathing was simplified as continuous inhalation through the nose. Fluid flow and particle trajectories were simulated over seven discrete orientations relative to the oncoming wind (0, 15, 30, 60, 90, 135, 180 degrees). Sensitivities of the model simplification and methods were assessed, particularly the placement of the recessed nostril surface and the size of the nose. Simulations identified higher aspiration (13% on average) when compared to published experimental wind tunnel data. Significant differences in aspiration were identified between nose geometry, with the smaller nose aspirating an average of 8.6% more than the larger nose. Differences in fluid flow solution methods accounted for 2% average differences, on the order of methodological uncertainty. Similar trends to mouth-breathing simulations were observed including increasing aspiration efficiency with decreasing freestream velocity and decreasing aspiration with increasing rotation away from the oncoming wind. These models indicate nasal aspiration in slow moving air occurs only for particles <100 um.
Keywords
Aerosols; Air-flow; Particle-aerodynamics; Analytical-models; Simulation-methods; Mathematical-models; Breathing; Inhalants; Airborne-particles; Biological-effects; Exposure-levels; Humans; Men; Women; Nasal-cavity; Workers; Work-environment; Models; Analytical-processes; Samplers; Sampling; Dust-inhalation; Dusts; Author Keywords: dust; dust sampling convention; inhalability; inhalable dust; low velocity; model; nose
Contact
T. Renée Anthony, Department of Occupational and Environmental Health, University of Iowa, 145 N. Riverside Drive, Iowa City, IA 52242
CODEN
AOHYA3
Publication Date
20140601
Document Type
Journal Article
Email Address
renee-anthony@uiowa.edu
Funding Type
Grant
Fiscal Year
2014
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R01-OH-009290; M062014
Issue of Publication
7
ISSN
0003-4878
Source Name
Annals of Occupational Hygiene
State
IA
Performing Organization
University of Iowa
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