<p>This study proposes a novel two-stage cyclone separator in which the number of inter-conduits is varied to redistribute the flow between stages, thereby enhancing fine particle separation. The design includes configurations with one, two, and four connections, applying both rectangular and circular cross-sections to analyze their effects on internal flow and particle collection. Computational fluid dynamics simulations using the Reynolds stress model are conducted to evaluate vortex symmetry and fine-particle collection efficiency. The results show that increasing the number of connections improves the flow stability and separation efficiency, with rectangular cross-sections consistently outperforming circular cross-sections. The optimized configuration demonstrates a significant improvement in ultrafine particle removal compared with conventional two-stage designs, confirming its potential as an effective strategy for fine particle control under complex flow conditions.</p>