다공튜브 형상변화에 따른 촉매 삽입형 Urea-SCR 머플러 내부유동 해석

Abstract

Abstract: This study reports a numerical analysis of the internal flow characteristics of the integrated urea-SCR muffler system with the various geometries of the multi-perforated tube which is set up between the muffler inlet and in front of SCR catalysts. The multi-perforated tube is generally used to disperse uniformly the urea-water sol-ution spray and to make better use of the SCR catalyst, resulting in the increased NO x reduction and decreased am-monia slip. The effects of the multi-perforated tube orifice area ratios on the velocity distributions in front of the SCR catalyst, which is ultimately quantified as the uniformity index, were investigated for the optimal muffler sys-tem design. The steady flow model was applied by using a general-purpose commercial software package. The air at the room temperature was used as a working fluid, instead of the exhaust gas and urea-water solution spray mixture. From the analysis results, it was clarified that the multi-perforated tube geometry sensitively affected to the for-mation of the bulk swirling motion inside the plenum chamber set in front of the SCR catalyst and to the uniformity index of the velocity distribution produced at the inlet of the catalyst.