Investigation into the existence of cyclone size providing the best separation efficiency

Mathematical models developed for estimating the separation efficiency of cyclone particle filters generally indicate that reducing the size of a cyclone increases its efficiency or decreases the critical particle diameter. The question of whether there is a limit to this tendency for cyclone size is important for efficient cyclone design. The main objective of this study was to determine the size of the cyclone that provides the smallest critical diameter in geometrically similar cyclones under identical fluid inlet conditions. To achieve this aim, mathematical modelling of this phenomenon was carried out, resulting in the derivation of an expression for the limiting value. A strong correlation was observed between the theoretical predictions and experimental data. For a high-efficiency Stairmand cyclone, the minimum cyclone diameters were calculated as 28 mm and 10 mm at inlet velocities of 5 and 10 m/s, respectively. It was concluded that for geometrically similar cyclones, this limiting value is influenced by the inlet velocity; specifically, higher inlet velocities shift the limiting cyclone diameter toward smaller sizes.