This paper presents the effect of liquid droplet injection on separation efficiency in a cyclone separator using a numerical procedure. As common cyclone separators (dry cyclone separators) unable to collect fine particles efficiently, the liquid droplets are injected into cyclone chamber, to improve separation efficiently of cyclone separators. The major focus is the study of the effect of liquid droplet injection, on the collection of particles with diameter smaller than 10 microns. The problem of isothermal flow-field in cyclone separators is formulated in terms of the Eulerian partial differential equations of the gas phase conservation of mass and momentum An algebraic Reynolds stress model (ASM), is also used to involve turbulence efefcts. A Lagrangian approach is employed to predict the trajectories of discrete phase (particles and droplets) in cyclone chamber. The effect of velocity fluctuations on separation efficiency is studied by use of instantaneous fluctuating velocities instead of the mean velocities. The solid particles and liquid droplets are introduced in a converged flow solution. The injected droplets collect particles by use of one or more several collection mechanisms. In cyclone separators, Impaction is the principle collection mechanism. The detailed effects of droplet injector design parameters (such as nozzle angle, droplet velocity and droplet diameter) on the collection performance, are investigated. The calculations show that a droplet trajectory is strongly influenced by droplet size. The simulation results also show that injection of liquid droplet can enhance separation efficiency of cyclone separator, especially for particles <5 μm. Numerical results also indicate that taking fluctuation velocities into account would decrease separation efficiency of cyclones. Comparisons between predicted results and measurements show good agreement.

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