| 摘要: | 本論文運用計算流體力學（CFD）對帶有渦流室之流化床（Fluidized Bed with
Vortex Chamber, FBVC）系統中的氣固流動行為進行詳細的數值模擬研究。研究採
用兩種建模方法：其一為歐拉-歐拉（Eulerian-Eulerian, EE）模型，以模擬整體流場
的水力行為；其二為結合高密度離散相模型（Dense Discrete Phase Model, DDPM）
的擴展 EE 模型，用以捕捉顆粒尺度的動態特性。本研究系統性地探討多項幾何設
計與操作參數對流化穩定性、均勻性與顆粒流失的影響，包括顆粒直徑、進氣口配
置、進氣速度、顆粒注入角度、供料速率、排氣出口幾何以及顆粒形狀等。
根據 EE 模型模擬結果，較小顆粒與更多切向進氣口有助於促進混合；然而，過高
的進氣速度會加劇顆粒夾帶（entrainment）現象。DDPM 模型則顯示，若顆粒以與
渦旋方向對齊的 45° 注入角進入系統，可有效提高顆粒留存率。此外，出口幾何對
顆粒流失亦具關鍵影響；5–6 mm 倾斜設計可在穩定流動與可控排放之間取得最佳
平衡。研究也指出，非球形顆粒因其流動性與懸浮能力較低，會進一步影響床層穩
定性。
顆粒流失為本系統的一項重要挑戰；因此，本研究強調須透過優化出口設計（包括
角度與寬度）與進料條件（注入角與速率）來降低早期流失風險。雖然本研究受限
於二維建模與理想化顆粒假設，其結果仍提供對氣固流動機制的深入了解。未來可
進一步納入三維模擬並考慮顆粒多分散性（即顆粒大小分布），以更貼近實際工業
系統。此外，引入顆粒磨損（因碰撞導致尺寸減小）與凝聚現象（如濕氣或靜電造
成顆粒附著）等物理因素，亦可用來更真實地評估長期操作下的顆粒流失與流化性
能。本研究結果對渦流流化床技術之優化設計提供了實用建議與理論基礎。;This thesis presents a detailed computational investigation of gas-solid flow behavior in a
Fluidized Bed with Vortex Chamber (FBVC) system using Computational Fluid Dynamics
(CFD). Two modeling approaches are employed: The Eulerian-Eulerian (EE) model to
simulate bulk hydrodynamic behavior, and an extended EE model coupled with the Dense
Discrete Phase Model (DDPM) to capture particle-scale dynamics. The study
systematically examines the effects of key design and operational parameters including
particle diameter, air inlet configuration, inlet velocity, injection angle, feed rate, outlet
geometry, and non-particle drag force on fluidization stability, uniformity, and particle
loss/discharge. EE-based results show that smaller particles and a higher number of
tangential inlets enhance mixing, while excessively high inlet velocities increase particle
entrainment. The DDPM analysis reveals that a 45° tangential injection angle aligned with
the vortex flow yields optimal particle retention, and that outlet geometry significantly
influences loss dynamics. A 5-6 mm inclined outlet offers the best trade-off between flow
stability and controlled discharge. Moreover, non-spherical particles demonstrate reduced
mobility and weaker suspension, further affecting bed behavior. Particle loss/discharge is
identified as a critical challenge, with results emphasizing the need for both outlet and
feeding optimization specifically, tuning outlet angle and width, as well as selecting
appropriate injection angles and feed rates, to minimize premature entrainment. Although
limited by two-dimensional modeling and applied particle assumptions, the study provides
key insights into gas-solid flow mechanisms. Future work should incorporate threedimensional modeling and account for polydispersity, where particles have a range of sizes,
to better reflect industrial systems. In addition, modeling particle attrition (size reduction
due to collisions) and cohesion (inter-particle forces from moisture or electrostatics) will
allow for a more realistic evaluation of long-term particle loss/discharge and fluidization
performance. The findings provide practical design guidance and establish a solid
foundation for the advanced modeling and optimization of vortex fluidized bed technology. |
