Computational simulation of worker exposure using a particle trajectory method.
Flynn-MR; Chen-M; Kim-T; Muthedath-P
Ann Occup Hyg 1995 Jun; 39(3):277-289
A computational simulation of worker exposure using a particle trajectory method was developed. The time dependent air flow around a worker was computed by the discrete vortex method, improved to speed up calculations. The flow of air around a worker was calculated by modeling the worker as a two dimensional elliptical cylinder. The concentration of particles released into the two dimensional flow field was time averaged, as were the velocity fields. The numerical simulations developed captured the Strouhal number (shedding frequency) over a range of Reynolds numbers, but the eddy shape and size might not be simulated as well. Despite the limitations, reasonable concentrations were possible for the plane of the source and the breathing zone. Computer predicted concentrations produced excellent agreement with measurements of breathing zone concentrations obtained using a mannequin. The authors conclude that the method is limited because the flow around a worker is a three dimensional phenomenon; however, the results suggest that selection of the appropriate Lagrangian time scale and averaging over an appropriate computational breathing zone can minimize this drawback.
NIOSH-Publication; NIOSH-Grant; Control-technology; Mathematical-models; Ventilation; Occupational-exposure; Air-quality-measurement; Airborne-particles; Time-weighted-average-exposure; Breathing-atmospheres; Dust-velocity
Environmental Sciences & Engr University of North Carolina CB 7400 Rosenau Chapel Hill, NC 27599-7400
Annals of Occupational Hygiene
University of North Carolina Chapel Hill, Chapel Hill, North Carolina