Evaluation of plume rise models from tall stacks in moist atmospheres

摘要

This paper presents a plume rise model, called M1, capable of dealing with complex atmospheric profiles -wind shear and thermal stratification- since it performs a numerical integration, along the plume trajectory, of a set of differential equations derived from the balance of mass, momentum and energy in the plume. The model deals with a mixture of four components -dry combustion gas, dry air, water vapor and liquid water- to allow for condensation and/or re-evaporation within the plume. Profile shapes of temperature and velocity of the plume cross sections are assumed to have axisymmetrical distributions and they can vary with distance to stack. 20 field observations of plume trajectories and final rise in two power plants were compared to the numerical model M1 predictions and a set of classical formulations used for regulatory models (M5 to M7). M1 performs better under all circumstances and can be used to calculate impacts downwind.