A DIRECT APPROACH TO THE DESIGN OF CYCLONES FOR AEROSOLMONITORING APPLICATIONS

During the past four decades, many investigators have attempted to discover models to describe the performance of cyclone aerosol selectors. These efforts were in general not successful and resulted in "semi-empirical" relationships of narrow application. The introduction of regulatory size-selection curves for air-monitoring applications means that it is no longer adequate to predict only the median cut point (D50) of a size selector. This further complicates the search for a useful cyclone model. Building on previous work, a completely empirical investigation was devised which has resulted in the development of the "Family" approach to cyclone design, and a method for predicting both the D50 cut point and the shape (or slope) of the selection curve. Three cyclone families have been developed and tested, which cover the current range of requirements for size selective particulate sampling. Although this empirical approach does not advance the physical understanding of cyclone separators, it does provide a practical means to design cyclones for specific applications.