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대형 디젤엔진용 SCR 시스템의 암모니아 슬립 억제를 위한 인젝터의 형상 및 위치에 관한 수치적 연구

Title
대형 디젤엔진용 SCR 시스템의 암모니아 슬립 억제를 위한 인젝터의 형상 및 위치에 관한 수치적 연구
Other Titles
Numerical Study on the Injector Shape and Location of Urea.SCR System of Heavy.duty Diesel Engine for Preventing NH₃ Slip
Author
김우승
Issue Date
2006-12
Publisher
한국자동차공학회
Citation
한국자동차공학회논문집, v. 14, No. 1, Page. 68 - 78
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 cannot 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.
URI
http://www.dbpia.co.kr/journal/articleDetail?nodeId=NODE00666181&language=ko_KRhttp://repository.hanyang.ac.kr/handle/20.500.11754/108954
ISSN
1225-6382
Appears in Collections:
COLLEGE OF ENGINEERING SCIENCES[E](공학대학) > MECHANICAL ENGINEERING(기계공학과) > Articles
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