Аннотация:The continuous tightening of diesel emission standards forces engine manufacturers to develop and improve solutions for reducing exhaust gas pollutant emissions. In recent years, exhaust gas aftertreatment systems have become widespread. Urea-based selective catalytic reduction systems are a well-established technique in terms of reducing nitrogen oxide emissions. In the designing process of these systems, computational fluid dynamics is an important tool. It reduces development time and costs but requires reliable mathematical models of complicated physical and chemical processes. In this study, a numerical model for the simulation of urea-water-solution injection, evaporation and thermal decomposition, using commercial CFD code ANSYS Fluent, is presented. Simulations were performed under different gas flow conditions. The obtained numerical results were compared with experimental data available from the literature. The interaction between the urea-water-solution spray and the turbulent flow field created by the static mixers was studied. Different designs of static mixers were investigated in terms of ammonia conversion efficiency, mixing performance and associated pressure losses