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덕트 내 오염물질 퇴적 방지를 위한 벽면유동 제어에 관한 해석적 연구
이방욱(Banguk Lee),이지근(Jeekeun Lee) 대한설비공학회 2013 설비공학 논문집 Vol.25 No.5
Technologies for preventing contaminants deposition are a key issue in a modern duct system. When particulate matters deposit inside the exhaust pipes, which are widely used in the Urea-SCR system to reduce NOx emission from heavy duty diesel engines, many problems arise associated with increased flow resistance and corrosion. Therefore, the development of the urea deposition avoidance technologies is being treated as an important issue of the Urea-SCR system. An analytical study was carried out to investigate the effects of the wall flow around the mixer with the variation of the mixer housing surrounding and supporting the mixer, which is designed to increase the wall flow and then to reduce droplet deposition. The housing angles and the position of the mixer were changed:angles of 0°, 1° , 2° , and 3° , and mixer positions of 0 L, 0.5 L, and 1 L. The axial velocity distributions, maximum velocity, the half-width, and momentum distribution of the wall flow were investigated to examine the effect of the mixer-housing assembly geometry.
Urea-SCR 시스템 Urea-Salt 퇴적방지를 위한 믹서하우징 형상변화에 따른 유동제어에 관한 연구
이방욱(Banguk Lee),이지근(Jeekeun Lee) 한국자동차공학회 2011 한국자동차공학회 학술대회 및 전시회 Vol.2011 No.11
The Urea-SCR system commercialized shows a remarkable performance to reduce NOx emission in heavy duty diesel engines. However, Urea-water solution injected upstream a mixer, which is set up inside a exhaust pipe to promote exhaust gas-atomized droplet mixing, bumps up against the wall of a exhaust pipe as the droplets flowing downstream through the exhaust gas. The urea deposited on the wall of the exhaust pipe is changed into the Urea-salt, resulting in the decreased life-time of the SCR catalysts and the increased exhaust emission. For this reason, the development of the urea deposition avoidance technologies is being treated as an important issue of the Urea-SCR system. Analytical study was carried out to investigate the effects of the flow characteristics around the mixer with the variation of the mixer housing surrounding and supporting the mixer, which is designed to increase the wall flow and then to reduce droplet deposition. The flow characteristics was simulated by applying for K-e RNG model, and the vane angles and the position of the mixer were changed : Angle of 0°, 1°, 2°, 3°, and Mixer positions of 0Lh, 0.5Lh, 1Lh. Analytical results were verified by the experimental results using a Hot-wire anemometer system. The wall flow onto the exhaust pipe was improved with changing the angle of the mixer housing, and the wall flow improved more when the position of the mixer was on 0Lh.