本研究使用一種具有螺旋結構及高比表面積的不規則填充料，並利用計算流體動力學( CFD )模擬在兩相逆流條件下，螺旋環在填充塔內的流體動力學行為，最後以實驗室級實驗進行驗證。在CFD模擬中，採用流體體積( volume of fluid, VOF )多相流模型計算氣體和液體的相互作用，發現Green-Gauss Node-Based與多面體網格的轉換為影響梯度計算精準度的關鍵因素，並將模擬結果與實驗相比，能夠得到良好的一致性。另外，因為流場幾何結構的複雜性，計算上需要耗費相當大的計算成本。因此本研究提出薄膜螺旋環以簡化模擬模型，此方法不但能降低計算成本，而且能夠更準確的評估螺旋環的流體動力學性質。最後我們將螺旋環與傳統拉西環相比，結果顯示螺旋環的特殊結構在濕潤面積以及持液率有更好的表現，並且擁有更穩定的壓力降及範圍更寬廣的操作條件。

In this study, a random packing with helical structure and high surface area was used, and the hydrodynamic behavior of helical ring in two-phase countercurrent flow system was simulated by computational fluid dynamics ( CFD ). The results were validated by in-house experiments. In the CFD simulation, the fluid of volume ( volume of fluid, VOF ) multiphase flow model was used to calculate the interaction between gas and liquid. It was found that the adoption of Green-Gauss Node-Based and polyhedral mesh was the critical method for the accuracy of gradient calculation. Comparing the simulation results with the experiment, good consistency could be obtained. In addition, because of the complexity of the flow field geometry, computational costs were expensive. Therefore, this study proposed a film helical ring to simplify the model. This method could not only reduce the computational cost, but also more accurately evaluated the hydrodynamic properties of the helical ring. Finally, we compared the helical ring with the traditional Raschig ring. The results showed that the structure of helical ring has better performance in the wetted area and liquid hold, and has more stable pressure drop and a wide operating ratio of liquid-to-gas flow.

摘要................................................i
Abstract...........................................ii
致謝辭..............................................iii
目錄................................................1
圖目錄..............................................3
表目錄...............................................4
第一章 文獻回顧.....................................5
第二章 模擬方法......................................11
2.1數值方法介紹.......................................11
2.2統御方程式.........................................11
2.2.1連續方程式(Continuity Equation)..................11
2.2.2動量守恆方程式(Momentum Conservation Equation)....12
2.2.3紊流方程式(Turbulence Equation)..................12
2.2.4表面張力(Surface Tension).........................13
2.2.5高斯節點梯度計算(Green-Gauss Node-Based)...........14
2.3新型填充料結構......................................15
2.4填充物堆疊與流場模型建立.............................16
2.5網格品質處理........................................18
2.6流場邊界條件設定.....................................20
2.7模擬計算方法與收斂條件................................22
2.8水力性質的定義及計算..................................23
第三章 實驗方法..........................................24
3.1實驗設備..............................................24
3.2液氣接觸面積分率......................................26
3.3持液率...............................................26
3.4壓力降...............................................27
第四章 結果與討論........................................28
4.1複雜流場的梯度計算校正.................................28
4.2真實結構模型與簡化結構模型的比較........................31
4.3螺旋環與傳統拉西環水力性質比較..........................37
第五章 結論...............................................39
參數表...................................................40
文獻參考..................................................44

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