Swirl tube flow pattern

An essential feature of this new design is a better controlled gas flow pattern in the coating zone. This is achieved by application of a guiding system in which the gas flow is accelerated, stabilized, and given a precise amount of swirl, which eliminates slugging, often seen in traditional coaters, and stabilizes multi-tube systems. Particles are... 

Fig. 3.1.1. Sketch of a tangential-inlet cyclone with the flow pattern indicated. The coordinate directions are shown, normally the 2-axis coincides with the axis of the cyclone or swirl tube. To the right, the radial distributions of the axial and tangential gas velocity components are sketched. It is understood that the dust outlet may be the Uquid outlet for the case of a demisting cyclone...

This completes om short discussion of flow pattern and pressure drop. We now tmn to the models. By far most of the modeling work has concentrated on cyhnder-on-cone cyclones with tangential inlets. We will therefore talk of cyclones in these sections. Very little direct work on the modeling of the flow pattern and the pressure drop in swirl tubes has been published our... 

A third assumption made in cyclone performance models is that the radial velocity is uniform over CS. The radial velocity is the smallest velocity component, and it is more difficult to measure with LDA than the other components. We can again resort to CFD to get an impression of the flow pattern. Figure 4.4.4 shows profile plots of the radial velocity distribution in both a cylindrical swirl tube and a cylinder-on-cone cyclone with slot inlet. 

We have examined some of the most widely acclaimed and cited cyclone models. There is one more way of predicting the flow pattern, pressure drop and the separation efficiency in cyclones and swirl tubes, however by Computational Fluid Dynamics, or CFD for short. 

The existence of such a break-down is supported by the experiments of Escudier et al. (2005). It also appears to be present in a swirl tube, at least one with a conically shaped vortex finder (sketched in Fig. 15.1.12g). Figures 7.3.6 and 7.3.7 shows the flow pattern in the gas outlet and downstream tubing of a... 

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