Numerical simulation of cascaded cyclone separator for nanosize aerosol

Among the conventionally used sampling methods, the cyclone-based air samplers are considered to be the most effective and simplest method. However, the collection efficiency of these commercially available air samplers is found to be limited. It reaches a critically low value for nanosized aerosol particle separation. This paper presents a computational fluid dynamics-based numerical simulation of a cascaded cyclone separator planned to be used for the separation of nanosize airborne viruses. The turbulent incompressible flow model with a volume of a fluid formulation is employed during the simulation. The discrete particle method is used to model and track the nanosized aerosol particle trajectory. The fluid properties of the airborne viruses are assigned to the aerosol particles during the simulation to obtain realistic flow results. The Stairmand high-efficiency cyclone geometry is redesigned by the numerical experiment method to obtain high collection efficiency for nanosize aerosol particles, and a new set of geometrical ratios has been proposed. Then the effect of inlet flow rate on the collection efficiency is presented. The fluid flow dynamics are observed, and the detailed distribution of particles collected in various portions of the cascaded cyclone is presented. The present cascaded cyclone could separate nanosized aerosol particles with an average efficiency of more than 93%.