多孔ドラフトチューブ付き噴流層の流動特性 [in Japanese] Hydrodynamics of a Spouted Bed with a Porous Draft Tube [in Japanese]
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多くの孔を設けたドラフトチューブ付き噴流層の流動特性として, アニュラス部ガス流量割合, 粒子循環速度およびチューブ内の圧力損失, 粒子ホールドアップを調べ, 通常のドラフトチューブの場合と比較した.<BR>その結果, それらに与える設計因子であるエントレメント区間やチューブ径および操作因子であるガス流速, 粒子径の影響を実験的に検討し, 通常のドラフトチューブの場合との相違点を明らかにした.またガス流速の増加に伴って粒子循環速度が増加する操作範囲について, 相関式を提示した.さらにチューブ内のガス流速の変化に伴って, 粒子ホールドアップがほぼ一定である安定な噴流化領域, 粒子ホールドアップが大きく増加する間欠的噴流化領域およびチューブ内の粒子の閉塞状態の存在が, 目視や圧力損失の検討から認められた.
The flow rate of the gas in the annular section, the particle circulation rate, the pressure drop and the particle hold-up in the tube section were measured for a spouted bed fitted with a porous draft tube. The results were more or less different from the data of a spouted bed fitted with a conventional (solid) draft tube.<BR>The experimental relationships between the items as described above and the design factors of distance of entrainment zone and its diameter, and operating factors such as the gas velocity and the particle diameter were determined. A correlation concerning the particle circulation rate was presented in the operating region where the particle circulation rate increased in proportion to the gas velocity.<BR>In addition, three patterns of particle flow in both porous and solid draft tubes were recognized by determining the pressure drops and the particle hold-up in the tube. These three patterns could be described as follows : a stable spouting region in which the particle hold-up was insensitive to the gas velocity ; a pulsing spouting region in which the particle hold-up varied with the gas velocity ; and a clogging region within the tube.
- Chemical engineering
Chemical engineering 22(3), 615-621, 1996-05-10
The Society of Chemical Engineers, Japan