Limit of centrifugal separation in a free vortex

Abstract

Two vortex experiments are cited that show that the common analysis of centrifugal separators does not adequately predict the separation of small particles in j et-driven swirl separators. The common analysis ignores the interference of the particle with the vortex flow in cases where the flow deviates from the solid vortex type. This interference, in connection with viscous effects, causes substantial fluid pressure forces opposing the separation of the particle. With the viscous effects approximated by analogy with straight flow conditions, the limit for the separation of particles in a free vortex is derived. It becomes apparent that particles with a density much higher than that of the flow medium can move toward the vortex center instead of being separated. In zones where the flow deviates from the free vortex conditions, the inward movement may be stopped resulting in the stabilization of the particles. The present considerations pertain quite generally to the movement of small particles in curved flow's.