A Example Calculation of the Throat Area

As with more conventional cyclones, a vortex stabilizer may also be installed in swirl tube type cyclones. Nevertheless, for reasons given above, one has to be most careful if the swirl tube is to be installed in a multicyclone configuration. One has to ensure that the underflow configuration can handle the flow maldistribution that always accompanies multicyclone configurations. Some examples of vortex stabilizers can be found in Chap. 13, which discusses demisting cyclones. 

A swirl tube equipped with a 6-element inlet vane of 5 mm thickness is to be used to separate entrained droplets from a carrier gas. The vane will be fitted into a 150 mm ID cyclone and will have an inner diameter of 100 mm. The vanes trailing edge will be 30° off the horizontal. 

Find the vane s cross-sectional area normal to flow and the corresponding throat velocity for a gas rate of 0.20 m /sec. Also compute the tangential component of this velocity. 

Therefore, the velocity of the jets emerging from the vane pack is = 

It is this tangential component of the inlet velocity that generates the force that separates the droplets from the gas. On the other hand, it is the axial component of the inlet throat velocity that most affects the downward velocity component of the liquid spiraling down the cyclone walls. 

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