CFD-aided design of mixers for the urea injection

The performance of a Selective Catalytic Reduction SCR systems in a modern Diesel engines is strongly related to the urea-water solution injection system, to vaporization of liquid droplets, decomposition of urea vapor to ammonia (NH3) and mixing of the NH3 vapor from the urea injector to the SCR catalyst inlet. To improve the evaporation and the mixing of urea vapor with the exhaust gas, passive flow mixing devices (mixers) are commonly adopted in SCR systems.