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

The Korean Society of Mechanical Engineers (대한기계학회)
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Internal Flow Analysis of Urea-SCR System for Passenger Cars Considering Actual Driving Conditions

운전 조건을 고려한 승용차용 요소첨가 선택적 촉매환원장치의 내부 유동 해석에 관한 연구

  • Moon, Seong Joon (Gas Engine System R&D Center, Korea Automotive Technology Institute(KATECH)) ;
  • Jo, Nak Won (Gas Engine System R&D Center, Korea Automotive Technology Institute(KATECH)) ;
  • Oh, Se Doo (Gas Engine System R&D Center, Korea Automotive Technology Institute(KATECH)) ;
  • Lee, Ho Kil (Gas Engine System R&D Center, Korea Automotive Technology Institute(KATECH)) ;
  • Park, Kyoung Woo (Dept. of Mechanical Engineering, Hoseo Univ.)
  • 문성준 (자동차부품연구원 가스엔진기술연구센터) ;
  • 조낙원 (자동차부품연구원 가스엔진기술연구센터) ;
  • 오세두 (자동차부품연구원 가스엔진기술연구센터) ;
  • 이호길 (자동차부품연구원 가스엔진기술연구센터) ;
  • 박경우 (호서대학교 기계공학과)
  • Received : 2015.05.19
  • Accepted : 2016.01.24
  • Published : 2016.03.01
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Abstract

Diesel vehicles should be equipped with urea-selective catalytic reduction(SCR) system as a high-performance catalyst, in order to reduce harmful nitrogen oxide emissions. In this study, a three-dimensional Eulerian-Lagrangian CFD analysis was used to numerically predict the multiphase flow characteristics of the urea-SCR system, coupled with the chemical reactions of the system's transport phenomena. Then, the numerical spray structure was modified by comparing the results with the measured values from spray visualization, such as the injection velocity, penentration length, spray radius, and sauter mean diameter. In addition, the analysis results were verified by comparison with the removal efficiency of the nitrogen oxide emissions during engine and chassis tests, resulting in accuracy of the relative error of less than 5%. Finally, a verified CFD analysis was used to calculate the interanl flow of the urea-SCR system, thereby analyzing the characteristics of pressure drop and velocity increase, and predicting the uniformity index and overdistribution positions of ammonia.

디젤 차량의 유해배출가스인 질소산화물 저감을 위해서는 정화성능이 우수한 요소첨가 선택적 촉매환원장치가 장착되어야 한다. 본 연구에서는 3차원 오일러리안-라그랑지안 전산유체해석을 통해 요소첨가 선택적 촉매환원장치의 수송현상에 따른 화학반응과 다상유동 특성을 수치적으로 예측한다. 이때, 수치적인 분무형상은 가시화실험에서 측정된 분사속도, 분무관통길이, 분무반경, 평균액적지름과 비교를 통해 보정되었다. 그리고 해석 결과는 실제 엔진 및 차량 시험에서 측정한 질소산화물 저감효율과 비교를 통해 검증되었으며, 상대오차 5% 이하의 정확도를 보여준다. 검증된 전산모델은 요소첨가 선택적 촉매환원장치의 내부유동해석에 사용되었으며, 이를 통해 압력강하와 속도증가 특성을 분석하고, 암모니아의 농도균일도와 과잉분포 위치를 예측한다.

Keywords

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