Small-Particle Collection Efficiency of Vertical Cylinders in Flows of Low-Intesity Turbulence

A study of the forward collection efficiencies of paper-coated glass and copper cylinders (diameters of 7.5 and 4.0 cm) was conducted in a wind tunnel in which the flow was turbulent. Dibutyl phthalate droplets of MMD 1.3 microns were collected in air-flow velocities of 16.8, 12, and 8.3 mph. Deposition by inertial impaction was precluded by selection of these particle sizes, wind velocity, and cylinder size. The forward collection efficiencies were less than 1% in all cases (greater for the paper-coated glass cylinders than for the paper-coated copper). In general, the forward collection efficiency increased with the reciprocal of the cylinder diameter and was greater at 16.8 mph than at 12.0 and 8.3 mph. At the turbulence intensities used in this work (0.5%, 1.8%, and 4.7%), intensity of turbulence had no effect on forward collection efficiency.