Computational fluid dynamics investigation of particle inhalability

Abstract

This study uses computational fluid dynamics to investigate particle aspiration at the low air velocities typical of occupational settings. A realistic representation of a human head on a simpler geometric torso was positioned facing the wind ( 0.2 , 0.4 m s - 1 ) , and breathing was simulated using constant inhalation ( 1.8 , 4.3 m s - 1 ) . Aspiration was simulated using laminar transport for particles 0.3– 116 μ m . Results from the 0.4 m s - 1 freestream and 4.3 m s - 1 inhalation rate compared well with results from the literature for smaller particles. For particles ⩾ 68 μ m , simulations yielded smaller aspiration efficiencies than reported in experiments. For all low velocity conditions studied, the aspiration efficiency curve dropped well below the 50% recommended by the ACGIH in the forward-facing orientation. Additional investigation of aspiration efficiency at other orientations relative to the wind is recommended to fully investigate aspiration efficiency for large particles in occupational environments.