Study On The Influence Of Different Swirl-generated Ways On The Flow Field And Performance Of Cyclone Separator

Cyclone separator is of various kinds and could be classified into tangential entry cyclone and axial entry cyclone.The vortex-generated vane of axial entry cyclone could be classified into helical vane and petal-shaped vane.Generally speaking,the swirling intensity of axial entry cyclone is lower than that of tangential one,thus leading lower centrifugal force and efficiency than those of a tangential entry cyclone with identical geometries.However,few contrastive research has been found concerning the tangential and axial cyclone and we have no idea about the exact differences between the flow field of two cyclones,and whether axial entry cyclone could obtain the same efficiency as tangential cyclone.Therefore,this thesis is to investigate the flow filed,efficiency and pressure drop of helical vane and petal-shaped vane by CFD modeling and performance testing,and also compare them to tangential entry Stairmand cyclone with identical body diameter.Detailed research contents are as follows.The results suggest that vortex-generated ways have significant effects on flow field out of the vortex finder and separation space and result in different performances.Compared to tangential-inlet cyclone,although guide vane can effectively reinforce the scouring effect in annular space,it intensifies the non-uniformity of flow field at annular space of outer wall of vortex finder and also lead to severe swing of vortex end.The guide vane decreases the static pressure differences,conversion effect of vortex in separation space,hence limiting the separation performance.Properly optimizing the outlet area of guider could enhance the separation performance,symmetry of flow field and operating flexibility;In terms of low tangential velocities and radial pressure gradients,it is inferred that the vortex conversion effects of guider are inferior to that of tangential-inlet cyclone,but it is superior in stable flow field,low pressure drop,low dust-entrainments and quick separation,which makes up for absent vortex conversion effect.For guider-vortex finder,the effects of insertion depth of vortex finder on the efficiencies are affected byshort-cut flow,separation height and initial axial velocities.Shorter vortex finder can also satisfy the need of separation accuracy,and control large areas of coke at outer wall of the vortex finder.If the insertion depth is over low,the initial injection axial velocity of guider and pressure features can effectively decrease particles entrained by the short-cut flow;If the insertion depth is over high,insufficient separation height,partial dust-entrainment and radial short-cut flow would decrease efficiencies.The effects of initial injection axial velocities of guider are limited,but have significant effects on short-cut flow and flow field of annular space,which are needed to be further studied.