Numerical modelling of particle capture efficiency and fine particles sampling with series impaction sizer

Session A1: Environmental Fluid Mechanics - Theoretical, Modelling and Experimental Approaches

Numerical modelling of particle capture efficiency and fine particles sampling are important for designing a series impaction sizer. This study generated liquid particles using an ultrasonic atomizing nozzle to examin the particle capture efficiency of the series impaction sizer. The aerosol number concentrations of the inlet and outlet of the series impaction sizer were measured by an aerodynamic particle sizer. Numerical analysis including the flow field of the impaction sizer was calculated by solving the Navier-Stokes equations in the cylindrical coordinate and the governing equations were discretized by means of the finite volume method. The particle equations of motion in the series impaction sizer were solved numerically for the particle capture efficiency. The results show that the particle collection efficiencies of the series impaction sizer with the jet diameter of 10mm are lower than those of the series impaction sizer with the jet diameter of 8.5mm at same flow rate. In addition, for the series impaction sizer using the foam depth of 3mm and 6mm, the cut-off aerodynamic particle diameter for the jet diameter of 10mm and 8.5mm is 2.91mm and 2.47mm, respectively. The cut-off aerodynamic particle diameter of the series impaction sizer with the jet diameter of 10mm for the foam depth of 6mm and 9mm is 2.52mm. The study conducted the numerical calculations for the particle capture efficiencies of the series impaction sizer. The numerical results were found to be consistent with experimental data for the particle capture efficiencies of the series impaction sizer.