A rotating bluff-body disc for reduced variability in wind tunnel aerosol studies.
Koehler KA; Anthony TR; van Dyke M; Volckens J
Ann Occup Hyg 2011 Jan; 55(1):86-96
A rotating bluff-body disc (RBD) was developed to reduce spatiotemporal variability associated with sampling supermicron aerosol in low-velocity wind tunnels. The RBD is designed to rotate eight personal aerosol samplers around a circular path in a forward-facing plane aligned with the wind tunnel cross section. Rotation of the RBD allows each sampler to traverse an identical path about the wind tunnel cross section, which reduces the effects of spatial heterogeneity associated with dispersing supermicron aerosol in low-velocity wind tunnels. Samplers are positioned on the face of the RBD via sampling ports, which connect to an air manifold on the back of the disc. Flow through each sampler was controlled with a critical orifice or needle valve, allowing air to be drawn through the manifold with a single pump. A metal tube, attached to this manifold, serves as both the axis of rotation and the flow conduction path (between the samplers and the vacuum source). Validation of the RBD was performed with isokinetic samplers and 37-mm cassettes. For facing-the-wind tests, the rotation of the RBD significantly decreased intra-sampler variability when challenged with particle diameters from 1 to 100 mm. The RBD was then employed to determine the aspiration efficiency of Institute of Occupational Medicine (IOM) personal samplers under a facing-the-wind condition. Operation of IOM samplers on the RBD reduced the between-sampler variability for all particle sizes tested.
Sampling equipment; Aerosol sampling; Aerosols; Particle aerodynamics; Air flow; Air samples; Air sampling equipment; Air sampling techniques; Sampling methods; Samplers; Pumps; Vacuum equipment; Testing equipment;
Author Keywords: aerosol sampling; IOM sampler; wind tunnel
John Volckens, Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523-1681, USA
Grant; Cooperative Agreement
Grant-Number-R21-OH-009114; Cooperative-Agreement-Number-U50-OH-008085; Grant-Number-T42-OH-008491
Agriculture, Forestry and Fishing
Annals of Occupational Hygiene
Colorado State University - Fort Collins