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이중 공기공급 이유체 선회노즐의 내부 형상이 분무 특성에 미치는 영향
강신명(Shinmyoung Kang),최윤준(Yoonjun Choi),우재문(Jaemoon Woo),김덕진(Duckjin Kim),이지근(Jeekeun Lee),노병준(Byungjoon Rho) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5
The regulations to reduce the exhaust emissions from vehicles are becoming increasingly stringent and encompassing more types of vehicles. In the case of heavy duty diesel engines, the Urea-SCR system is currently considered to reduce the NOx emission as a proved technology, and it is widely studied to get the high performance and durability. However, the injection nozzles occur some problems, including the nozzle clogging, deposition of urea-water solution on the inner wall of exhaust pipe. In this study, the effects of nozzle cap geometry, the length to diameter ratio(l<SUB>o</SUB>/d<SUB>o</SUB>) on the spray characteristics were investigated. The mean velocity, AMD and SMD distributions of the sprays were measured using a 2-D PDA system along the centerline and radial direction. As the experimental results, the higher length to diameter ratio(l<SUB>o</SUB>/d<SUB>o</SUB>) affects the increase of axial mean velocity and the decrease of radial mean velocity. The AMD and SMD increased with the length to diameter ratio(l<SUB>o</SUB>/d<SUB>o</SUB>), as well.
Two-Fluid Urea-SCR 분무노즐의 유동특성 및 분무구조에 관한 실험적 연구
강신명(Shinmyoung Kang),김의수(Euisoo Kim),박설혜(Sulhye Park),이지근(Jeekeun Lee) 한국자동차공학회 2007 한국자동차공학회 지부 학술대회 논문집 Vol.- No.-
Diesel engines are widely used in the modern industrial fields. However, the government regulations for environments are becoming increasingly stringent and encompassing more types of vehicles, such as diesel engines. The after-treatment system is a effective method to reduce the exhaust emission with keeping high efficiency of engine. The Urea-SCR system is the effective solution to reduce NOx among them. The injected urea-solution is converted into ammonia by heating the exhaust gas, then the ammonia is mixed with an exhaust gas. NOx is reduced by chemical reaction of the mixture. However, the non-reacted ammonia passes through the SCR system without chemical reaction so that the ammonia slip takes place. Therefore the precise control of urea-solution injecting from the nozzle is major factor of the Urea-SCR system. The spatial concentration and distributions of the spray, which determines the performance of the nozzle, are major factor in the Urea-SCR system. In this work, the flow and spray characteristics of the two-fluid Urea-SCR spray nozzle were measured with an air and liquid ratio(ALR). The variation of injection quantities is dependent upon a duty ratio, supplying liquid pressure and air flow-rate. Particularly, the flow-rate of carrier air is very important factor to determine the injection quantities. In addition, the spray structure;spray angle, penetration were measured using a PIV system.
이중 공기공급 이유체 선회노즐의 유량비 변화에 따른 미립화 특성에 관한 실험적 연구
강신명(Shinmyoung Kang),이지근(Jeekeun Lee),노병준(Byungjoon Rho) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.10
The regulations to reduce the exhaust emissions from vehicles are becoming increasingly stringent and encompassing more types of vehicles. In the case of heavy duty diesel engines, the Urea-SCR system is currently considered to reduce the NOx emission as a proved technology, and it is widely studied to get the high performance and durability. In the Urea-SCR system, urea-water solution is injected into the exhaust pipe using the specially designed nozzle with high precision dosing unit. However, the injection nozzles occur some problems, including nozzle clogging, deposition of urea-water solution on the inner wall of exhaust pipe. In this study, the atomization characteristics of the dual air supplying twin-fluid swirl nozzle were investigated experimentally using PIV and PDA systems. The effect of assist air flowrate supplying from the dual air port was investigated. The mean velocity, turbulent intensity and SMD distributions of the sprays were measured along the centerline and radial direction. As the experimental results, the higher axial velocity is observed in the central part of the spray, and the SMD decreased with the increase of ALR.