This paper tends to investigate the performance of a separator cyclone used in cement industries in Iran. This investigation was performed using CFD modeling, which is validated by other valid studies. Separator cyclone performance includes of two important parameters as pressure drop and collection ratio. In this presented study, the pressure drop has been considered to assess the performance of the cyclone. This assessment follows by changing geometrical parameters of the cyclone as its outlet diameter and height. Beside these geometrical parameters, two fluid parameters are investigated as the inlet velocity and outlet pressure. At the end 4 specified models and the CFD model of main cyclone are compared by considering fluid flow parameters, circulation, and finally cyclones pressure drop. This paper suggests the best parameters to be changed which make the cyclone more efficient. Results show that from investigating parameters, increasing the inlet velocity to 25 m/s has the most effective impacts on cyclone efficiency. پرونده مقاله