Investigation Of Unsteady Flow And Fluid-Solid Coupling In Cyclone Separators

With the rapid development of modern industry,the cyclone separator in FCC unit is facing new problems.Because of more sophisticated equipment and more stricter environmental regulation,the separation efficiency of the separator for small particles,especially less than 5 ?m,is urgently needed.With the large scale of the third stage cyclone,the fatigue problem caused by the vibration of the cyclone tube structure has been paid more and more attention.In this paper,the multi physical field coupling software Ansys Workbench is used to study the unsteady flow and the vibration of the structure.The results showed that the flow field inside the separator is obviously influenced by the structure of the exhaust pipe.By changing the structure of the exhaust pipe,the inner vortex pulsation frequency can be changed.There were two main frequencies of the static pressure pulsation in the flow field,the lower frequency was the inner vortex oscillation frequency,and the higher frequency was the rotation frequency of the precessing vortex core.With the gas velocity of the entrance increased,the frequency and amplitude of the flow field gradually increased along the height direction,reached the maximum at the hopper and drop leg.Through the analysis of the vibration of the wall under the coupled interaction,it was found that the structural vibration was a kind of forced vibration.The vibration of the structure stayed stable still until damping a certain period of time.The vibration of the structure was affected by the mass distribution and the constraint condition.With the decreased of the height,the vibration intensity also decreased.Due to the influence of boundary conditions and constraints,the structural resonance of the separator was possible.Through the analysis of structural strength of the separator,the positions of stress concentration included the connection between exhaust pipe and cylinder section,and between cone section and dust hopper.Through adjusting the installation of constraint,Separator vibration could be improved,the fatigue failure could also be avoided.