The Virtual Cyclone: A Device for Nonimpact Particle Separation

The virtual cyclone, a geometrically uncomplicated device that separates particles from a How stream by nonimpact particle separation, is discussed. In contradistinction to a cyclone, the particle-laden How is deHected from its original direction by a wall that curves away from the original How direction, rather than into it. The computational Huid dynamics code FIDAP (Fluid Dynamics International) is used to perform two-dimensional fluid-How and particle-motion calculations for a representative device geometry. Flow patterns are found to be insensitive to Reynolds number for values above 100 regardless of whether the How is laminar or turbulent. Particle-motion calculations for laminar-How cases indicate that the virtual cyclone geometry examined accomplishes nonimpact particle separation. An approximate analytical relation describing virtual cyclone nonimpact particle separation is developed and found to be in agreement with the numerical simulations.