Numerical analysis of the injection direction of Urea-Water sprays for the ammonia generation in realistic operating conditions.
2022-01-0701
03/29/2022
- Event
- Content
- During the past decades, increasingly tighter NOx emission limitations for diesel engines has implied greater development of the Selective Catalytic Reduction (SCR) for emission reduction purposes. The Urea-Water Solution (UWS) injection process plays a major role in the SCR efficiency both in the near-field, as well as in the far field. In order to understand the droplet breakup and mixing of the UWS with the surrounding air under different operating conditions, a computational campaign has been set up to do so. Computational Fluid Dynamics (CFD) allow to have a proper understanding of the physical phenomena taking place within the injection chamber, without the need of building up an experimental facility. The main objective of the present study is to recreate the spray injection process, as well as the chemical processes that the UWS spray undergoes, and analyze the optimal injection direction to maximize the amount of ammonia generated during the injection process. For it, an Eulerian-Lagrangian framework has been employed to track the evolution of the injected droplets within a Reynolds-Averaged Navier-Stokes (RANS) turbulence formulation. Typical injection pressures have been tested and realistic exhaust velocities have been applied. The results obtained comprise from the amount of ammonia generated for the three injection directions tested, to the rate of reaction of the UWS spray. The optimal injection direction resides close to the 60o with respect to the direction of the incoming exhaust gases, if compared to the original injection angle, which was set to 90ooriginally.
- Citation
- Payri, R., Marti-Aldaravi, P., Bracho, G., and Marco, J., "Numerical analysis of the injection direction of Urea-Water sprays for the ammonia generation in realistic operating conditions. ," SAE Technical Paper 2022-01-0701, 2022, .