Hydrocyclones are devices used in solid-liquid and liquid-liquid separations, in which the substances involved present significantly different densities. Although the hydrocyclone geometry is simple, the internal flow is complex; then small changes in its characteristic dimensions can improve or harm its performance. In this context, this research aimed to study the effect of the interaction between two variables on separation in a novel designed hydrocyclone: underflow orifice diameter and vortex finder length. Experiments with a dilute aqueous suspension and CFD simulations with water-only single-phase system were carried out. The results showed that the 0.167 D-U/D-C majored the total separation efficiency and reduced the energy consumption, although it increased the underflow-to-throughput ratio as it raised the downward axial velocity. Moreover, it was observed that the 0.100 D-U/D-C is more suitable to achieve higher concentrations of solids on the underfiow stream with reasonable total separation efficiency. It was also verified that intermediate values of vortex finder length favored the separation by enhancing the centrifugal field in this novel hydrocyclone through the intensification of the tangential velocity, as elucidated the CFD simulations. Considering a high total efficiency as well as the solid concentration at underfiow stream without major damage to energy expenditure, the results of experimental tests and fluid dynamics simulations indicated the best configuration for the vortex finder and underfiow orifice. (C) 2018 Elsevier B.V. All rights reserved.