Aerosol particle deposition in an obstructed turbulent duct flow

Abstract

A computational scheme for simulating aerosol particle dispersion and deposition in turbulent flows in passages with complex geometry is developed. A thermodynamically consistent rate-dependent algebraic stress model is used to simulate the mean turbulent flow fields. The instantaneous turbulence fluctuation is simulated as a continuous Gaussian random field. The Brownian motion is modeled as a white noise process. The particle equation of motion including the Stokes drag, Brownian and Saffman forces is used. The computational model predictions for particle deposition velocity in a turbulent channel flow are compared with the experimental data and earlier simulation results. Several digital simulations for aerosol particle transport and deposition in a duct with an obstructing block are performed. The corresponding capture efficiencies of rectangular and trapezoidal blocks for different particle Stokes number are evaluated and discussed. It is shown that the deposition rate decreases significantly as the shape of the obstruction becomes more streamlined.