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http://dx.doi.org/10.3795/KSME-B.2008.32.11.897

A Study on Numerical Modeling of the Induced Heat to Gaseous Flow inside the Mixing Area of Ammonia SCR System in Diesel Nox After-treatment Devices  

Bae, Myung-Whan (경상대학교 기계항공공학부)
Syaiful, Syaiful (경상대학교 기계항공공학부)
Publication Information
Transactions of the Korean Society of Mechanical Engineers B / v.32, no.11, 2008 , pp. 897-905 More about this Journal
Abstract
Selective catalytic reduction(SCR) is known as one of promising methods for reducing $NO_x$ emissions in diesel exhaust gases. $NO_x$ emissions react with ammonia in the catalyst surface of SCR system at working temperature of catalyst. In this study, to raise the reacting temperature when the exhaust gas temperature is too low, a heater is located at the bottom of SCR reactor. At an ambient temperature, ammonia is radially injected perpendicular to the exhaust gas flow at inlet pipe and uniformly mixed in the mixing area after being impinged against the wall. To predict the turbulent model inside the mixing area of SCR system, the standard ${\kappa}\;-\;{\varepsilon}$ model is applied. This work investigates numerically the effects of induced heat on the gaseous flow. The results show that the Taylor-$G{\ddot{o}}rtler$ type vortex is generated after the gaseous flow impinges the wall in which these vortices influence the temperature distribution. The addition of heat disturbs the flow structure in bottom area and then stretching flow occurs. Vorticity strand is also formed when heat is continuously increased. Constriction process takes place, however, when a further heat input over a critical temperature is increased and finally forms shed vortex which is disconnected from the vorticity strand. The strong vortex restricts the heat transport in the gaseous flow.
Keywords
Ammonia SCR System; Diesel $NO_x$ After-treatment Device; Numerical Modeling; Induced Heat; Gaseous Flow; Working Temperature; Vortex;
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Times Cited By KSCI : 1  (Citation Analysis)
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