• 作者： Lu, Wei-Ming; Chiu, Hung-Tzu
• 中文摘要： 為了測試氣泡在多段通氣攪拌槽內之行為,本研究導出了氣泡運動方程式,配合由FLUENT所求出之流場,利用數值方法解出四個系統:包括了單殺Rushton攪拌翼系統、兩段Rushton攪拌翼系統、A310與Rushton攪拌翼系統、三段Rushton攪拌翼系統。利用Lagrangian方法,基於局部能量消散速率,氣泡之結合與破裂現象也一併被考慮在運動方程式中,此模式並被延伸解多段攪拌槽中局部氣泡大小,氣泡大小分布,及局部和整體氣含量。結果顯示在檔板前方,因為攪拌翼造成強烈液體徑向速度之影響,使得氣泡在此處最容易發生結合,使大部分氣泡沿著檔板上昇,故只有少於26%的氣體會經過上段攪拌翼。
• 英文摘要： To examine the behavior of bubbles in multiple- impeller aerated vessels, the equations of motion of bubbles are obtained and solved numerically based on the flow field calculated by FLUENT for four systems, including one Rushton impeller, dual-Rushton impellers, A310 and Rushton impellers and tri-Rushton impellers. Coalescence and breakage functions, based on the local energy dissipation rate, are incorporated into the model of bubble motion equations by using the Lagrangian approach. The model is extended to calculate the local bubble size, volumetric bubble size distribution, and the local and total gas hold-up in the multi-impeller mixing tank. The results show that the bubble coalescence often occurs in front of baffles due to the high radial liquid velocities induced by the impellers. As a result of adding the volume of bubbles passing through the upper impellers, less than 26% of the gas fed to the lowest impeller flows through the upper impeller.
• 中文關鍵字： 氣泡運動; 分散; 聚結; 多段攪拌翼; 攪拌槽
• 英文關鍵字： Bubble Motion; Break-Up; Coalescence; Multiple Impeller; Stirred Vessel