급가감속 운전에 따른 듀얼 모노리스형 촉매변환기 내의 유동 균일도와 압력 강하에 관한 연구

Abstract

Conversion efficiency, durability and pressure drop of automotive exhaust catalysts are dependent on the flow distribution within the substrate. Conventional porous medium approach assuming monolith resistance based on one-dimensional laminar flow for simulating the flow through automotive exhaust catalysts overpredicts the flow uniformity in the monolith. In this study, additional pressure loss accounting for entrance effects due to oblique flow incident on the front face of monolith as a consequence of flow separation and recirculation within the diffuser is considered and incorporation of an additional pressure loss improves the predictions for the maximum flow velocity within the substrate. A numerical study of three-dimensional unsteady incompressible non-reacting flow inside various dual-monolith catalytic converters for the rapid acceleration/deceleration driving has also been conducted.