Fig. 1 shows a schematic diagram of the gas-cyclone used in this
study. The cyclone diameter was set at 72 mm and each dimension
was determined from experimental data that proved superior in
classification performance [4]. The secondary flow injection method
in the upper part of the cyclone as shown in Fig. 1 was used to improve
classification performance [5]. The performance of the cyclones were
examined by use of the partial separation efficiency Δη defined by: