The cyclone separator is widely used for particle separation in industries because of ease in manufacturing and maintenance free working capability. It has also been an automobile component used in air intake system. It's necessary to understand the flow of air and particles inside the cyclone separator for the design of cyclone separator. Its performance depends upon operational and geometrical parameters. This study is focused on geometric parameter in which a numerical simulation has been carried out to understand the effect of air and particle flow on varying the cone height of cyclone separator using ANSYS 15.0. The analysis involves determining pressure drop at different inlet velocity with corresponding change in cone height of the cyclone separator. The results were obtained for different velocity condition with maximum of 8% of error. Moreover, collection efficiency for cyclone separator was also determined by varying particle size from 0.01 to 10 micron. Decreasing cyclone height led to increase in tangential velocity thus increasing the cyclone efficiency. © 2019 IOP Publishing Ltd. All rights reserved.