Flow in Cyclones

The steady, laminar, incompressible fluid flow in cyclone collectors is governed by the Navier-Stokes equations ... 

An appropriate model of the Reynolds stress tensor is vital for an accurate prediction of the fluid flow in cyclones, and this also affects the particle flow simulations. This is because the highly rotating fluid flow produces a. strong nonisotropy in the turbulent structure that causes some of the most popular turbulence models, such as the standard k-e turbulence model, to produce inaccurate predictions of the fluid flow. The Reynolds stress models (RSMs) perform much better, but one of the major drawbacks of these methods is their very complex formulation, which often makes it difficult to both implement the method and obtain convergence. The renormalization group (RNG) turbulence model has been employed by some researchers for the fluid flow in cyclones, and some reasonably good predictions have been obtained for the fluid flow. 

For the turbulent flow in cyclones, the key to the success of CFD lies with the accurate description of the turbulent behaviour of the flow [8], To model the swirling turbulent... 

The washing action of the circulating flows in cyclones with wide angles,... 

Driessen MG. Theory of flow in cyclone. Rev Ind Mining, Special Issue 4 pp 449 61, 1951. 

In general, many of the features of the flow in cyclones can be understood when considering the effects of the swirhng motion on the axial and radial flow pattern. This issue will be discussed in Chap. 4. 

In general, wall friction has a profound effect on the flow in cyclones and on cyclone performance. We shall discuss this in Chap. 5, when investigating the effect of cyclone body length on cyclone pressure drop and separation efficiency. We shall also discuss the effect of friction in Chap. 9 when looking at the effect of solids loading, which also turns out to be a consequence of the effect of the solids on the wall friction. 

Having discussed the flow in cyclones, and the principles behind some models, we are able to anticipate to an extent the effects of increasing cyclone... 

Fig. 7.1.6. LES simulations of the flow in cyclones (Prasad and Bakker, 1999). a is the intantaneous flow, and b the flow averaged over 0.25 s...

De Sonza FJ, Salvo RD, Martins DAD Large eddy simulation of the gas—particle flow in cyclone separators, Sep Purif Technol 94 61-70, 2012. http //dx.doi.0rg/lO.lOl6/j. seppur. 2012.04.006. 

Derksen JJ, Van den Akker HEA, Sundaresan S Two-way coupled large-eddy simulations of the gas-soHd flow in cyclone separators, AIChE J 54 872—885, 2008. http / dx.doi.org/ 10.1002/aic.ll418. 

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