Modeling and simulation of urea-water-solution droplet evaporation and thermolysis processes for SCR systems

A numerical model of urea-water-solution (UWS) droplet evaporation and thermolysis is proposed. An adjustment coefficient depending on exhaust temperature is introduced to correct the Abramzon-Sirignano evaporation model. The evaporation characteristics, decomposition efficiency of a single UWS droplet and deposit formation are simulated. Temperature is the decisive factor for urea thermolysis, different temperatures will result in different deposit components.142