Numerical analysis of pollutant dispersion from the industry stacks: Effects of Schmidt number and wind velocity

Based on steady-state Renormalization Group (RNG) k-ε turbulence model, Computational Fluid Dynamics (CFD) simulations of pollutant SO₂ dispersion in the neutrally stable atmospheric boundary layer are made with the commercial code CFX for different Schmidt numbers (Sct) and wind velocities. So the results of concentration contours on the ground and sedimentation velocities of SO₂ are gained, and then these are compared with the Gaussian model. It is shown that in all cases: SO₂ concentration in the heavy polluted area increases with S_ct; increase in wind velocity accelerates SO₂ dispersion, but the heaviest polluted location does not change with the valve of wind velocity. When S_ct=0.7, SO₂ concentration distribution from RNG k-ε turbulence model resembles that from the Gaussian model. The comparison however cannot clearly indicate which Sct accords completely with which type of dispersion due to a large number of other factors in the simulations, including turbulence modeling, near-wall treatment limitations, etc.