대한기계학회논문집B (Transactions of the Korean Society of Mechanical Engineers B)

  • 제38권12호
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  • Pages.1017-1026
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  • 2014
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  • 1226-4881(pISSN)
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  • 2288-5324(eISSN)
대한기계학회 (The Korean Society of Mechanical Engineers)
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촉매삽입형 Urea-SCR 머플러 다공튜브 형상변화에 따른 NOx 저감 특성에 관한 연구

Study on NOx Reduction with Multi-Perforated Tube Geometry in Integrated Urea-SCR Muffler

  • 투고 : 2014.05.12
  • 심사 : 2014.07.21
  • 발행 : 2014.12.01
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초록

Urea-SCR 머플러 시스템 입구와 촉매 전단에 설치된 다공튜브는 우레아 수용액 분무의 균일분포, SCR 촉매 활용도 증대 및 암모니아 슬립을 방지하기 위해 사용되고 있다. 다공튜브의 오리피스 면적비 변화가 머플러 챔버 내부유동 특성에 끼치는 영향이 상용 소프트웨어를 이용하여 해석적으로 조사되었다. 다공튜브 오리피스 면적비 변화는 촉매 전단에 설치된 챔버 내부의 벌크 선회유동 형성과 촉매 전단 속도분포의 균일도 지수에 큰 영향을 끼침을 보였다. 해석결과를 검증하기 위해 엔진실험이 ESC 및 ETC 모드에서 수행되었다. 엔진 실험결과 다공튜브 길이방향으로 보다 많은 유량이 흐르는 모델이 가장 높은 NOx 저감 효율을 나타냈으며, 이것은 높은 균일도지수 및 강한 선회유동을 나타내는 해석 결과와 일치됨을 알 수 있었다.

A multi-perforated tube is generally installed between the muffler inlet and in front of selective catalytic reduction (SCR) catalysts in the integrated urea-SCR muffler system in order to disperse the urea-water solution spray uniformly and to make better use of the SCR catalyst, which would result in an increase nitrogen oxide ($NO_x$) reduction efficiency and a decrease in the ammonia slip. The effects of the multi-perforated tube orifice area ratios on the internal flow characteristics were investigated analytically by using a general-purpose commercial software package. From the results, it was clarified that the multi-perforated tube geometry sensitively affected the generation of the bulk swirling motion inside the plenum chamber set in front of the SCR catalyst and to the uniformity index of the velocity distribution produced at the inlet of the catalyst. To verify the analytical results, engine tests were carried out in the ESC and ETC modes. Results of these tests indicated that the larger flow model in the longitudinal direction showed the highest NOx reduction efficiency, which was a good agreement with the analytical results.

키워드

참고문헌

  1. Zhang, X. and Romzek, M., 2007. "3-D Numerical Study of Flow Mixing in Front of SCR for Different Injection Systems," SAE Technical Paper 2007-01-1578.
  2. Girard, J., Snow, R., Cavataio, G. and Lambert, C., 2007. "The Influence of Ammonia to $NO_X$ Ratio on SCR Performance," SAE Technical Paper 2007-01-1581.
  3. Narayanaswamy, K. and He, Y., 2008. "Modeling of Copper-Zeolite and Iron-Zeolite Selective Catalytic Reduction (SCR) Catalysts at Steady State and Transient Conditions," SAE Technical Paper 2008-01-0615.
  4. Thompson, J., De Beeck, J. O., Joubert, E. and Wilhelm, T., 2008. "Case Studies of Urea SCR Integration on Passenger Cars Monitoring of Urea Inside the Tank During Hot and Cold Environment Test Missions," SAE Technical Paper 2008-01-1181.
  5. Huang, Z., Zhu, Z., Liu, Z. and Liu, Q., 2003. "Formation and Reaction of Ammonium Sulfate Salts on V2O5/AC Catalyst During Selective Catalytic Reduction of Nitric Oxide by Ammonia at Low Temperatures," Journal of Catalysis, Vol. 214, pp. 213-219. https://doi.org/10.1016/S0021-9517(02)00157-4
  6. Lee, J. S., Baik, D. S. and Lee, S. W., 2008. "Evaluation of SCR System in Heavy-Duty Diesel Engine," SAE Technical Paper 2008-01-1320.
  7. Rajadurai, S., 2008. "Improved $NO_x$ Reduction Using Wiremesh Thermolysis Mixer in Urea SCR System," SAE Technical Paper 2008-01-2636.
  8. Kim, T. K., Sung, Y. M., Han, S. H., Ha, S. J., Choi, G. M. and Kim, D. J., 2012. "Effect of Mixer Structure on Turbulence and Mixing with Urea-water Solution in Marine SCR System," Journal of the Korean Society of Marine Engineering, Vol. 36, No. 6, pp. 814-822. https://doi.org/10.5916/jkosme.2012.36.6.814
  9. Zhang, X., Romzek, M. and Morgan, C., 2006. "3-D Numerical Study of Mixing Characteristics of NH3 in Front of SCR," SAE Technical Paper 2006-01-3444.
  10. Weltens, H., Bressler, H., Terres, F., Neumaier, H. and Rammoser, D., 1993. "Optimization of Catalytic Converter Gas Flow Distribution by CFD Prediction," SAE Technical paper 930780.
  11. Johansson, A., Wallin, U., Karlsson, M., Isaksson, A. and Bush, P., 2008. "Investigation on Uniformity Indices Used for Diesel Exhaust Aftertreatment Systems," SAE Technical Paper 2008-01-0613.
  12. Oesterle, J. J., Calvo, S., Damson, B., Feyl, G., Neumann, F. and Rudelt, J., 2008. "Urea Systems in Focus - New Challenges and Solutions in the Development of Car and Commercial Vehicle Exhaust Systems," SAE Technical Paper 2008-01-1186.
  13. Oesterle, J. J., Calvo, S., Damson, B., Neumann, F. and Rudelt, J., 2008. "SCR Technology with Focus to Stringent Emissions Legislation," SAE Technical Paper 2008-01-2640.
  14. Karlsson, M., Wallin, U., Fredholm, S., Jansson, J., Wahlstrom, G., Schar, C. M., Onder, C. H. and Guzzella, L., 2006. "A Combined 3D/Lumped Modeling Approach to Ammonia SCR After-treatment Systems: Application to Mixer Designs," SAE Technical Paper 2006-01-0469.
  15. Lee, H. S., Ha, J. H., Pahn, L. O. and Lee, S. H., 2005. "An Internal Flow Analysis for Automobile Mufflers," Proceedings of KSAE, pp. 1804-1088.
  16. Han, K. T., 2005. "A Study on the Perforating Process of the Muffer Tube using FEM," Journal of the Korean Society of Marine Engineering, Vol. 29, No. 3, pp. 275-280.
  17. Jeong, S. J., Kang, W., Lee, J. J. and Kim, T. H., 2009. "Exhaust System Design for the Integrated Automotive Muffler," Transactions of KSAE, Vol. 17, No. 4, pp. 24-31.
  18. Lee, S. K., Moon, N. S. and Lee, J. K., 2012. "A Study on Exit Flow Characteristics according to the Orifice Configuration of Multi-perforated Tubes," Journal of Mechanical Science and Technology, Vol. 26, No. 9, pp. 2751-2758. https://doi.org/10.1007/s12206-012-0721-z
  19. Lee, S. K., Moon, N. S. and Lee, J. K., 2013, "Analysis of an Internal Flow with Multi-perforated Tube Geometry in an Integrated Urea-SCR Muffler" Journal of the Korea Society of Marine Engineering, Vol. 37, No. 5, pp. 500-508 https://doi.org/10.5916/jkosme.2013.37.5.500
  20. Fluent User Guide. 6.2, The RNG k-e Model, pp. 11-17.