Design of multi-stage contracted inlet duct for cyclone separators

Abstract

In this study, the multi-stage contracted inlet duct is designed for the cyclone separator to improve the separation efficiency. A numerical simulation using a four-way coupling method is implemented to calculate the inner flow field of a high-solid-loading industrial cyclone separator. The separation efficiency and pressure drop of the cyclone separators with various two-stage and three-stage contracted inlet ducts are estimated. The coordinates of the intersection points exert significant impacts on the inner flow pattern and performance of the cyclone separator. An orthogonal test is performed to obtain the optimal three-stage design. The results show that both the optimal two-stage and three-stage designs effectively improve the separation efficiency with a moderate rise in the pressure drop. However, the separation efficiency of the optimal two-stage design is higher than that of the optimal three-stage design despite the additional intersection point in the latter. It is also found that the two-stage design provides advantageous features for improving separation efficiency when compared to the three-stage design. The separation efficiency is enhanced if a three-stage design degenerates into a two-stage design. Furthermore, the multi-stage design with three or more intersection points can also degenerate into a two-stage design for higher separation efficiency, indicating that the two-stage design is the most suitable option for the contracted inlet duct. The optimal two-stage design in this study enhances the separation efficiency from 94.77% to 96.11% and increases the pressure drop by 187.04 Pa, which is less than one-tenth of the pressure drop of the original one-stage design.