EPTT 2022

13th Spring School on Transition and Turbulence

Assessment of a new hybrid turbulence model applied to cyclone separators

Submission Author: Rafaela Gomide Corrêa , MG
Co-Authors: Rafaela Gomide Corrêa, Francisco Souza
Presenter: Rafaela Gomide Corrêa

doi://10.26678/ABCM.EPTT2022.EPT22-0019

 

Abstract

Cyclones are devices that use the centrifugal acceleration to separate particles from a gas flow. The models as the current ones started to show up in the beginning of the twentieth century and their development was promoted by their simple construction, low manufacturing cost, lack of moving parts and relative ease of maintenance. The flow inside a cyclone, formed by the tangential feed under high pressure, is turbulent, multiphasic and complex. This flow is responsible for the separation, so it has been widely studied to understand and optimize the operation of this equipment. To analyze a fluid flow, one alternative is to solve the equations of continuity, momentum and energy. When there are particles in the flow, it is also necessary to solve equations for their motion, generating an equations system that is hard to solve analytically. Then it is required to use Computational Fluid Dynamics (CFD) and, to obtain a result that is similar to the reality, the turbulence model needs to be appropriate. For cyclones, the most used models are the Large Eddy Simulation (LES) and the Reynolds Stress Model (RSM). The first one can give more accurate results, but it needs a more refined mesh and has higher computational costs. So, to combine the advantages of these two models, the main objective of this research was to evaluate a new hybrid LES/RSM model applied to the cyclone’s flow. The results were compared to experimental data and with RSM model results. It showed that the grade collection efficiency curve obtained by the hybrid model is closer to the experimental one, even for the less refined mesh. Furthermore, the velocity field obtained by the two models were compared and the results were similar, but the hybrid model predicts more fluctuations. It suggests that resolving some of the length scales is important to the grade collection efficiency.

Keywords

cyclone, Hybrid LES/RSM, Large Eddy Simulation (LES), Reynolds Stress Model (RSM), Collection efficiency

 

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