Professional Articles

Dust Control

Industrial Dust Separators: CFD Analysis of Dilute Phase Cyclones

Cyclone separators are widely used for dust pollution control in bulk solids handling and processing industry and gas–solid separation for aerosol sampling or for product recovery in various industrial applications because of their geometrical simplicity, relative economy in capital and maintenance costs, low power requirement, flexibility and proven ability to perform in extremely harsh conditions. It facilitates continuous material removal with less clogging than a fabric filter.
The schematic diagram in Fig. 1. shows a standard reverse flow cyclone with tangential inlet. Though the operating principle of a cyclone is very simple, the turbulent flow-field is very complex due to presence of swirl and interaction between particles, fluid and walls. A tangential entry and cyclone geometry give rise to a strong swirling flow. The flow acquires a rotational movement (free or outer vortex) along the cyclone wall and it descends down to a certain axial location near the cyclone bottom where the axial velocity acquires a reverse flow (forced or inner vortex) towards the upward direction and finally exit through a central duct known as vortex finder. Particles entering the cyclone are rebound, re-circulated and re-entrained all along the outer and inner vortex and as a consequence the variables controlling the centrifugal force become highly complex. In fact, it has been shown that the centrifugal forces act upon only a small fraction of total particles. Body forces and particle interaction are the dominating parameters for controlling particle separation [1]. It has been found that the cyclone performance is very sensitive to fluid and particle properties, cyclone geometry and operating conditions.
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