Numerical study of the fluid flow and particle dynamics is presented by numerical techniques to characterize the performance of new design cyclone separators with one, two and three tangential inlets. The design of this cyclone is based on the idea of improving cyclone performance by increasing the vortex length. This cyclone differs from a conventional cyclone with the separation space. Instead of conical part, the separation space of this cyclone consists of an outer cylinder and a vortex limiter. The Reynolds averaged Navier-Stokes equations with Reynolds stress turbulence model (RSM) are solved by use of the finite volume method based on the SIMPLE pressure correction algorithm in the computational domain. The Eulerian-Lagrangian computational procedure is used to predict particles tracking in the cyclones. The velocity fluctuations are simulated using the Discrete Random Walk (DRW). In the results the effects of number of inlets on the different important parameters such as pressure drop, collection efficiency, axial velocity and turbulence are investigated and deeply discussed. Contours of velocity, pressure and turbulent kinetic energy within these cyclones with different number of inlets are shown. The results show that the cyclone with three inlets has more collection efficiency, less pressure drop and less turbulence distribution with respect to cyclones with one and two inlets which is good in cyclones performance. Generally it is recommended to use the new cyclone designs with higher number of inlets. (C) 2017 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.