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Simulation on the Optimum Shape and Location of Urea Injector for Urea-SCR System of Heavy-duty Diesel Engine to Prevent NH3 Slip
Technical Paper
2005-01-3886
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
In the past few years, considerable efforts have been directed towards the further development of Urea-SCR(selective catalytic reduction) technique for diesel-driven vehicle. Although urea possesses considerable advantages over Ammonia(NH3) in terms of toxicity and handling, its necessary decomposition into Ammonia and carbon dioxide complicates the DeNOx process. Moreover, a mobile SCR system has only a short distance between engine exhaust and the catalyst entrance. Hence, this leads to not enough residence times of urea, and therefore evaporation and thermolysis can not be completed at the catalyst entrance. This may cause high secondary emissions of Ammonia and isocyanic acid from the reducing agent and also leads to the fact that a considerable section of the catalyst may be misused for the purely thermal steps of water evaporation and thermolysis of urea. Hence the key factor to implementation of SCR technology on automobile is fast thermolysis, good mixing of Ammonia and gas, and reducing Ammonia slip. In this context, this study performs three-dimensional numerical simulation of urea injection of heavy-duty diesel engine under various injection pressure, injector locations and number of injector hole. This study employs Eulerian-Lagrangian approach to consider break-up, evaporation and heat and mass-transfer between droplet and exhaust gas with considering thermolysis and the turbulence dispersion effect of droplet. The SCR-monolith brick has been treated as porous medium. The effect of location and number of hole of urea injector on the uniformity of Ammonia concentration distribution and the amount of water at the entrance of SCR-monolith has been examined in detail under various injection pressures.
The present results show useful guidelines for the optimum design of urea injector for reducing Ammonia slip and improving DeNOx performance.
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Jeong, S., Lee, S., Kim, W., and Lee, C., "Simulation on the Optimum Shape and Location of Urea Injector for Urea-SCR System of Heavy-duty Diesel Engine to Prevent NH3 Slip," SAE Technical Paper 2005-01-3886, 2005, https://doi.org/10.4271/2005-01-3886.Also In
References
- Jeong Soo-Jin Kim Woo-Seung “A Study on the Optimal Monolith Combination for Improving Flow Uniformity and Warm-up Performance of an Auto-Catalyst” Chemical Engineering and Processing 42 879 895 2003
- Jeong Soo-Jin Kim Woo-Seung “Three-Dimensional Numerical Study on the Use of Warm-up Catalyst to Improve Light-off Performance” Detroit, Michigan SAE Paper No. 2000-01-0207 2000
- STAR-CD Ver.3.15 Users Manual Computational Fluid Dynamics Ltd. 2001
- Weltens, H. Bressler, H. Terres, F. Neumaier, H. Rammoser, D. “Optimization of Catalytic Converter Gas Flow Distribution by CFD Distribution” SAE Paper 930780 1993
- Pilch, M. Erdman, C. “Use of breakup time data velocity history data to predict the maximum size of stable fragments for acceleration-induced breakup of a liquid drop” Int. J. Multiphase Flow 13 6 741 757 1987
- Bai, C. Gosman, A.D. “Development of methodology for spray impingement simulation” SAE Paper 950283 1995
- Nagaoka, M. Kawazoe, H. Nomura, N. “Modeling fuel spray impingement on a hot wall for gasoline engines” SAE Paper 940525 1994
- Rich, B. R. “An Investigation of Heat Transfer from an Inclined Flat Plate in Free Convection” Trans. ASME 75 489 499 1953
- Mattavi J. N. Amann C. A. “Combustion Modeling in Reciprocating Engines,” Plenum Press 369 401 1980
- Koebel Manfred “Thermal and hydrolytic decomposition of urea for automotive selective catalytic reduction systems: Thermochemical and practical aspects” Ind. Eng. Chem. Res 42 2093 2100 2003