Design of wetted wall bioaerosol concentration cyclones

• Main Author: Seo, Youngjin
• Other Authors: McFarland, Andrew R
• Format: Others
• Published: 2013
• Subjects: Cyclone; bioaerosol
• Online Access: http://hdl.handle.net/1969.1/ETD-TAMU-2381; http://hdl.handle.net/1969.1/148442

A wetted wall cyclone is a device that delivers hydrosol in a single stage from which real-time detection of airborne particles can be readily achieved. This dissertation presents the design, development, and characterization of a family of wetted wall bioaerosol cyclone concentrators that consume very low power and are capable of delivering very small liquid effluent flow rate of highly-concentrated hydrosol. The aerosol-to-aerosol penetration cutpoint for the cyclones is about 1µm. The aerosol-tohydrosol collection efficiency for the 1250 L/min cyclone is above 90% for particle sizes greater than 2 µm at the 1 mL/min liquid effluent flow rate. The aerosol-to-hydrosol collection efficiency for the 100 L/min cyclone is above 85% for particle sizes larger than 2 µm at the 0.1 mL/min liquid effluent flow rate when it is operated at air flow-rate of 100 L/min. The pressure drop across the 1250 L/min and 100 L/min cyclones are approximately 22 inches of water and about 6.4 inches of water, respectively. A study, based on the empirically obtained aerosol-to-aerosol collection efficiency, was conducted to develop a performance modeling correlation that enables prediction of the aerosol performance as a function of the Reynolds number and Stokes number. Since the Reynolds number and Stokes number govern the particle motions in the cyclone, the aerosol performance could be expressed in terms of the Reynolds number and Stokes number. By testing the three cyclones (100, 300, and 1250 L/min cyclones) with several different air flow rates, the aerosol-to-aerosol collection efficiencies for wide range of the Reynolds numbers (3,500 < Re < 30,000) were able to be obtained. Performance modeling correlations for wetted wall cyclones show that the aerosol-toaerosol collection efficiency in the cyclone can be well predicted by the Reynolds number and Stokes number.