PERFORMANCE MODELING OF SINGLE-INLET AEROSOL SAMPLING CYCLONES

A technical basis has been developed which justifies using two nondimensional parameters: the ratio of the cutpoint particle diameter to the cyclone diameter, (D0.5/D(c)) and the flow Reynolds numbers, Re(f). An improved method has also been developed for the design of single-inlet aerosol sampling cyclones using these parameters in a semiempirical functional relation. This allows predictions to be made of aerodynamic equivalent particle (AED) cutpoint diameter for a Stairmand cyclone which has had an alteration to its outlet tube diameter. The correlation coefficient for the functional relationship is r2 > 0.99. Using a particular cyclone, a designer can hold the airflow rate constant and then predict how the particle cutpoint will change as the outlet tube diameter 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 experimental testing. Three outlet tube sizes (26.7, 42.9, and 68.3 mm) (inside diameter) were used in different combinations to vary the ratio of the outlet tube diameter to cyclone body diameter in the cyclone. Flow rates ranged from 16.3 to 124 L/min. The measured particle cutpoints ranged from 4.0 to 18.8 mum AED.