Inertial impaction of aerosol particles on cylinders at intermediate and high reynolds numbers

Abstract

The deposition of aerosols on an isolated cylinder was theoretically investigated for cross flow conditions. The full solution of the time dependent Navier-Stokes equations was used to model inertial deposition on cylindrical collector at 30 ≲ Re c ≲ 40,000. The solution of the vorticity-stream function formulation of the Navier-Stokes equation was based on an explicit finite difference scheme. The solution domain was divided into variable cylindrical cells near the obstacle (inner flow region), and rectangular cells far from the cylinder (outer flow region), to obtain an acceptable resolution for the entire flow field. The flow was started impulsively and Poisson's equation solved iteratively by the Gauss-Siedel method. The vorticity-transport equation was solved in Forward Time Centered Space (FTCS), where for the numerical stability, the convective terms were handled by employing an Upwind Differencing Scheme (UDS). The computed collection efficiencies are in good agreement with available experimental data, demonstrating a significant improvement over previous work. A short-cut equation based on statistical fit of all simulated efficiencies as a function of Reynolds numbers and inertial impaction parameter is also presented to compute the inertial collection efficiency of an isolated cylindrical collector.