抄録
Selective catalytic reduction (SCR) is known as one of the most promising methods for reducing NO_x emissions in diesel exhaust gases. The purpose of this study is to develop SCR catalytic filter device for reducing NO_x and soot emissions simultaneously in diesel combustion devices. SCR catalysts are used to reduce NO_x emissions. And the novel catalytic filters inside SCR system devised by authors are specially designed and manufactured to reduce soot particles. NO_x emissions react with ammonia in the catalyst surface of SCR device. Therefore, uniform distribution of NH_3 is one of the challenges in the novel design of SCR device. Three catalytic filters with 120° interval are vertically mounted under the horizontal plate. At an ambient temperature, ammonia is injected radially perpendicular to the hot air flow at inlet pipe. In the present paper, the ammonia distribution in the new design of SCR catalytic filter device is investigated by numerical modeling. Turbulent model of gaseous flow in the mixing area of SCR catalytic filter device, also, is predicted by using the standard κ - ε. The results show that the Taylor-Gortler type vortex is generated after the gaseous flow impinges the wall. An amount of ammonia is concentrated in the vortex core due to these vortices. It also shows that the ammonia distribution in the mixing area is affected by the injector placement.
