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EFFECT OF TURBULENT TO LAMINAR FLOW TRANSITION ON SURFACE REACTION AND PARTICLE DEPOSITION IN A SQUARE DUCT

Kenji Tanno
Central Research Institute of Electric Power Industry, 2-6-1 Nagasaka, Yokosuka-shi, Kanagawa, 240-0196, Japan

Hisao Makino
Energy Engineering Research Laboratory Central Research Institute of Electric Power Industry 2-6-1 Nagasaka, Yokosuka, Kanagawa, 240-0196, Japan

Ryoichi Kurose
Department of Mechanical Engineering and Science, and Advanced Research Institute of Fluid Science and Engineering, Kyoto University, Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto 615–8540, Japan

Satoru Komori
Department of Mechanical Engineering and Science Kyoto University Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto, 615-8140, Japan

Takenobu Michioka
Department of Mechanical Engineering, Kyoto University, Kyoto 606-8501; Environmental Science Research Laboratory Central Reseach Institute of Electric Power Industry 1646 Abiko, Abiko, Chiba, 270-1194, Japan

Résumé

A monolith reactor is widely used to reduce pollutant matter in the industrial field. A monolith reactor, which consist of many rectangular channels, although flue gas flows into the channel inlet in turbulent condition, flue gas transitions from turbulent to laminar flow due to the small hydraulic diameter of a single channel. In order to develop a higher performance reactor, optimize the maintenance schedule and extend lifetime of reactor, it is important to understand reaction and degradation mechanism in a monolith reactor. In this study, surface reaction behaviour occurred on the wall and particle adhesion behaviour is investigated performing a direct numerical simulation (DNS). The results show that both surface reaction and particle adhesion are promoted by turbulent eddies which exists in the upstream region. However, the region which exhibits the effect of turbulent eddies is different. For particle deposition, the effect of turbulent eddies exhibits only in the upstream region, whereas for surface reaction, such effect also exhibits in the downstream region. This is because of the remaining cross-sectional fluid motion caused by the inflow turbulence. The magnitude of the cross-sectional fluid motion is weak, hence such motion only affects gaseous flow and cannot affect heavy particle motion.