PERFORMANCE MODELING OF SINGLE-INLET AEROSOL SAMPLING CYCLONES

A technical basis has been developed which justifies using two nondime nsional parameters: the ratio of the cutpoint particle diameter to the cyclone diameter, (D0.5/D(c)) and the flow Reynolds numbers, Re(f). A n improved method has also been developed for the design of single-inl et aerosol sampling cyclones using these parameters in a semiempirical functional relation. This allows predictions to be made of aerodynami c equivalent particle (AED) cutpoint diameter for a Stairmand cyclone which has had an alteration to its outlet tube diameter. The correlati on coefficient for the functional relationship is r2 > 0.99. Using a p articular cyclone, a designer can hold the airflow rate constant and t hen predict how the particle cutpoint will change as the outlet tube d iameter is changed. Or, a designer can alter the system flow rate and keep the cutpoint the same by changing the outlet tube diameter. Three cyclone body diameters (38.10,57.15, and 88.90 mm) were used in exper imental testing. Three outlet tube sizes (26.7, 42.9, and 68.3 mm) (in side diameter) were used in different combinations to vary the ratio o f the outlet tube diameter to cyclone body diameter in the cyclone. Fl ow rates ranged from 16.3 to 124 L/min. The measured particle cutpoint s ranged from 4.0 to 18.8 mum AED.