The study of the process of assimilation of toxic components of the boiler flue gas in the atmosphere
By means of computational fluid dynamics a forecast study of the spread of the flue gases in the atmosphere from chimney stacks of conditional boilers of small capacity is carried out. Verification of the STAR-CCM+ software by solving a two dimensional problem of the distribution of harmful substances in the atmosphere from a point source, for which analytical solution is known, is conducted. In the study of a free-standing chimney stack at different wind speeds it is found out that the impact of wind speed on the distribution of the maximum concentrations of harmful substances in the flue plume depending on the distance from the chimney stack is slight. We propose a method which allows us to reduce the environmental risk of relatively low chimney stacks, which consists in installing external axial fans along the stacks. According to the results of the calculation, the fields of concentrations of toxic substances (CO, NO and NO <sub>2</sub>) and the range of flue gases are defined. It is shown that the installation of additional fans on chimney stacks greatly intensifies the process of turbulent mixing the hazardous substances with air that can significantly reduce the length of the flue plume.