Separation performance predictions of a Stairmand high‐efficiency cyclone

() Large-eddy simulations LES were performed on the gas flow in a Stairmand highefficiency cyclone at Res 280,000. The LES realistically represent the 3-D, time-dependent flow, including phenomena such as ®ortex core precession, and ®ortex breakdown. Quantitati®ely good agreement with measured ®elocity profiles is obser®ed, for both the time-a®eraged ®elocities and the ®elocity fluctuation le®els. The single-phase LES formed the starting point for modeling solid particle motion in the cyclone based on one-way coupling between the gas flow and the particles. It is shown that some details of the flow in the relati®ely small region in the ®icinity of the inlet ha®e strong influence on the separation process. Due to the long residence times of particles inside the cyclone, the concurrent simulation of gas flow and particle motion is a lengthy computational process. Therefore, three alternati®e ways of modeling particle motion were explored: a frozen-field approach, an eddy-lifetime model, and a periodic-flow approach. The results of these approaches are compared to the results of the concurrent simulation.

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