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정명희(Myeong Hee Jeong),쿠마레쉬 셀와쿠마르(Kumaresh Selvakumar),조원준(Won Jun Jo),김만영(Man Young Kim),이교우(Gyo Woo Lee),송제호(Je-Ho Song) 한국산학기술학회 2015 한국산학기술학회 학술대회 Vol.2015 No.1
최근 전 세계적으로 디젤엔진의 배기규제가 강화되는 추세이며, 그 중 질소산화물을 저감하기 위하여 암모니아를 환원제로 사용하는 Urea-SCR 시스템이 많이 사용되고 있다. 그러나 트랙터나 콤바인과 같은농기계의 경우 후처리 시스템 장착공간이 협소해 배기관의 길이가 충분하지 않거나 그 형상이 복잡해 질수 있다. 이로 인해 배기관 내에 분사된 요소수용액의 분해 및 혼합이 충분히 이뤄지지 않으면 SCR의NOx 저감률이 감소할 수 있어 복잡한 형상의 배기관에 대해 요소수용액의 충분한 혼합을 위한 실험 및수치해석 연구가 필요하다. 따라서 본 연구에서는 SCR 삽입형 촉매 머플러 전단의 배기관내 요소수용액의 혼합과 열해리 성능을 높이기 위하여 배기관내의 다공판 설치 유무에 따른 유동해석을 진행하였으며,이 결과로 SCR 삽입형 촉매 머플러 내부의 3차원 유동특성을 비교하였다.
정명희(Myeong Hee Jeong),김만영(Man Young Kim),장영운(Young Woon Jang),김남일(Namil Kim) 한국자동차공학회 2015 한국자동차공학회 부문종합 학술대회 Vol.2015 No.5
In recently, most of diesel vehicle have been adopted DPF system to reduce PM in engine emission. However, if DPF usage increases, ash and soot in engine exhaust gas accumulated in the DPF and pressure drop in the engine is increase. As a results an increase in pressure drop is cause of damage of a DPF and aggravation of engine performance. So, DPF cleaning is one of good solutions of DPF regenerations. In this study, numerical investigations on the flow characteristics according to direction alteration and then compare two cases. Two different models are side of the tank and middle of the tank for the pipe on the tank. Simulation results show that pressure drop for two cases is similar. However, it is different that streamline in the DPF and tank, velocity contour and so on. These results offer a practical guide to the best design of DPF cleaning system.
DPF가 장착된 촉매 삽입형 머플러 형상 최적화를 위한 수치해석 연구
정명희(Myeong Hee Jeong),김만영(Man Young Kim) 한국자동차공학회 2015 한국자동차공학회 학술대회 및 전시회 Vol.2015 No.11
The diesel engines are being widely used in many industrial fields, because the diesel engines have a higher durability, thermal efficiency, and less CO₂ emission than gasoline engines. However, compression ignition method of diesel generates many particulate matter (PM) and nitrogen oxides (NOx) in exhaust emission. Therefore, most of diesel vehicle have been adopted DPF system to reduce PM in engine emission. In this study, the perforated plate is installed inside the catalytic muffler to improve flow uniformity and then numerical investigations on the fluid flow characteristics are conducted in the catalytic muffler by changing shapes. After that, these results are compared and show that different velocity profiles and uniformity index. These results offer a practical guide to the best design of catalytic muffler with perforated plate for improving De-PM performance.
Perforated Plate 형상에 따른 촉매 삽입형 머플러 내부의 유동특성 연구
정명희(Myeong Hee Jeong),김만영(Man Young Kim) 한국자동차공학회 2014 한국자동차공학회 학술대회 및 전시회 Vol.2014 No.11
The use of perforated plate and tubes is common in applications such as vehicle exhaust silencers. Also, perforated plate flow conditioners designed to improve flow distribution upstream of an orifice plate flow meter typically have 50 -60% free area but these generally employ a non-uniform distribution of holes of several sizes to encourage the formation of a fully developed pipe flow velocity distribution. In this study, numerical investigations on the flow characteristics according to various perforated plate shapes and then comparing to case without perforated plate. Three different models are flat perforated plate and a convex perforated plate in the direction of inlet, and a convex perforated plate in the direction of outlet. Simulation results show that, pressure drop without reference to perforated plate shape is similar. However, it is different that velocity, turbulence kinetic energy contour, fully developed velocity location and so on. These results offer a practical guide to the best design of catalytic muffler with perforated plate.
효과적인 Ammonium Carbonate 승화를 위한 반응기 유동해석
정명희(Myeong Hee Jeong),안태현(Tae Hyun An),김만영(Man Young Kim),김홍석(Hongsuk Kim) 한국자동차공학회 2013 한국자동차공학회 학술대회 및 전시회 Vol.2013 No.11
Due to reinforced environmental regulations on vehicle emissions, Urea-based SCR(Selective Catalytic Reduction) that supplies SCR with a reductant by using urea water solution is used in order to reduce Nitrogen oxides (NOx) in the exhaust gas of the engine. But it has a number of issues at low temperatures, including freezing below - 12 ℃, solid deposit formation in the exhaust, and difficulties in supplying SCR with a reductant at exhaust temperatures below 200 ℃. On the other hand, ammonium carbonate, one of ammonia storage materials, has the low thermal decomposition temperature, so it generate the ammonia gas from the solid to the vapor at an exhaust temperatures below 200 ℃. Consequently, in this study, we did a numerical study for various figuration reactors heat and fluid flow by using exhaust gas heat to sublimate ammonium carbonate in the form of cartridges effectively.
가이드 베인에 의한 Solid SCR 반응기 내부의 열유동에 관한 수치 해석 연구
정명희(Myeong Hee Jeong),김만영(Man Young Kim) 한국자동차공학회 2014 한국자동차공학회 부문종합 학술대회 Vol.2014 No.5
Due to reinforced environmental regulations on vehicle emissions, urea-based SCR(Selective Catalytic Reduction) that supplies SCR with a reductant by using urea water solution is commonly used in order to reduce Nitrogen Oxides (NOx) in the exhaust gas of the diesel engine. But it has a number of issues at low temperatures, including freezing below -12 ℃, solid deposit formation in the exhaust, and difficulties in supplying SCR with a reductant at exhaust temperatures below 200 ℃. On the other hand, ammonium carbamate, one of ammonia storage materials, has the low thermal decomposition temperature, so it generate the ammonia gas from the solid to the vapor at an exhaust temperatures below 200 ℃. Consequently, in this study, numerical investigations on the fluid flow and heat transfer characteristics are conducted in a complex solid SCR reactor. According to the presence or absence of the guide vane in the solid SCR reactor configured with Ammonium Carbamate, we obtained the results that reactor with a guide vane is more effective in sublimation via internal heat and fluid flow analysis.
다공판이 장착된 촉매 삽입형 머플러의 유동특성에 관한 해석 연구
정명희(Myeong Hee Jeong),김만영(Man Young Kim),김홍석(Hongsuk Kim),송제호(Je-Ho Song) 한국산학기술학회 2014 한국산학기술학회 학술대회 Vol.- No.-
다공판과 다공튜브는 차량이나 선박의 배기 소음기로 널리 이용되어왔으며, flow conditioner는 유량계의 상류측에 설치되어 유동의 균일함을 높이고, 완전 발달 유동이 발생되는 길이를 짧게 만드는데 사용되어왔다. 또한, 촉매 삽입형 머플러는 머플러 내에 유해 배기가스를 저감시키는 촉매를 장착함으로써 차량 제작 시 촉매부와 머플러 두 부분을 고려했던 기존의 방식에서 머플러부만 고려하면 되는 장점이 있다. 그리고 촉매가 머플러 내부에 장착되어, 촉매를 차량에 장착할 때 필요한 부품 수 감소로 인한 경제적인 이득을 볼 수 있으며, 내충격성이 약한 촉매를 머플러가 보호하게 된다. 본 연구에서는 DOC와 DPF가 장착된 머플러를 고려하였으며, 촉매 삽입형 머플러 내부에 다공판을 장착하여 다공판에 의한 3차원 유동특성을 비교하였다.