本研究以二維軸對稱方式模擬碳粒在鐵水中的溶解現象，模型中使用層流模型搭配多孔介質模型，其碳的溶解率是由質量擴散速率控制，並比較文獻中球體的溶解現象，發現在低Re具有一致性的趨勢。
為了瞭解不同幾何對於溶解之影響，以特定流場下之不同幾何碳粒模擬其溶解過程中的形狀演變及原因。從模擬結果中發現，在高Re下碳溶解速率會受到回流區的影響;在低Re數下溶解速率則取決於碳粒與鐵水接觸表面積。此外，為了瞭解距離對於碳溶解之影響，故建立雙顆球體碳粒模型，探討球體在不同遠近時對於溶解過程之影響。依模擬結果顯示，在低Re及球體距離較近時，回流區處於高碳濃度，阻礙了下游球體的溶解速率，且呈現橢圓體型態，在距離較遠時，下游球體受到上游流場碳濃度影響較小，且球體發展成類似子彈型態。在高Re時，皆發展成錐體型態，此現象與碳濃度及回流區的影響有關。
更進一步探討球體粒徑大小對於溶解之影響，研究中將球體間距及流場固定下，分析其溶解趨勢發現在低Re，固定下游球體粒徑，將上游球體粒徑持續加大時，距離較近時皆需要耗費更長的時間進行溶解，且上游球體總是最先溶解完成，在高Re時，亦可觀察出相同情形。然而，當固定上游球體粒徑，改變下游球體粒徑，存在同時溶解完成的粒徑大小，當粒徑超過該值後，下游球體溶解所需時間將會大於上游球體的溶解時間。

In this study, the dissolution of carbon particle in liquid iron was simulated in the two-dimensional model with axisymmetric assumption. The laminar model and the single-phase-porous-media model were used to simulate the dissolution, and the carbon dissolution rate was dictated by the mass diffusion rate. Comparisons of the results with related references have found similar trend at low Re number.
In order to understand the effects of various geometries on dissolution, the particle-shape evolution under the specific flow fields was observed. From the simulation results, the rate of carbon dissolution at high Re number was affected by the recirculation zone, and at low Re number the dissolution rate was depended on the magnitude of contact area between carbon particles and liquid iron. In addition, the dual-sphere carbon model was established to investigate the effect of sphere distance. It is found that the carbon concentration in the recirculation zone hinders the dissolution rate of the downstream sphere at low Re and in neighboring place, and it gradually developed into an ellipsoidal shape. At farther place, the upstream field has relatively little effect on downstream spheres. The sphere developed into a bullet type. At both of neighboring place and farther place at high Re, the sphere developed into a cone shape, and the reasons are related to the generation of recirculation zone and the carbon concentration.
This study further investigated the effect of sphere size on dissolution. The sphere space and flow field were fixed in this study, and the dissolution trend was analyzed. At low Re, the particle size of the downstream sphere was fixed and the particle size of the upstream sphere continued to increase, and it needed more time to dissolve not only at neighboring place but also at farther place. The upstream sphere completed the dissolution first, and the same situation can be observed at high Re. However, when the particle size of the upstream sphere was fixed and the diameter of the downstream sphere was changed, the specific particle size can dissolve in the same time. If the downstream particle size further increases, it has to spend more time to dissolve.

論文審定書 i
誌謝 ii
摘要 iii
Abstract iv
目錄 v
圖目錄 vii
表目錄 ix
符號說明 x
第一章 序論 1
1.1 前言 1
1.2 研究動機 2
1.3 文獻回顧 3
1.3.1轉爐發展與技術 3
1.3.2碳溶解機制 4
1.3.3其他物質縮減機制 6
1.4 研究背景與目的 8
1.5 本文架構 9
第二章 數學模型與求解方法 10
2.1數學模型 11
2.2模型假設與統御方程式 12
2.2.1模型假設 12
2.2.2統御方程式 13
2.3邊界條件 15
2.4數值方法 15
2.5格點測試 15
第三章 結果與討論 17
3.1滲透性倒數(1/C1)分析 18
3.2球體簡易關係式與暫態模型比較 21
3.3不同Re下各幾何所需之溶解時間 22
3.3.1 Re=6.19之碳溶解行為 24
3.3.2 Re=30.93之碳溶解行為 28
3.3.3 Re=61.86之碳溶解行為 32
3.3.4 Re=185.58之碳溶解行為 36
3.4間距對雙球體溶解行為之影響 40
3.4.1雙球體在Re=6.19流場下之溶解 40
3.4.2雙球體在Re=185.58流場下之溶解 41
3.5不同球體顆粒深度對溶解之影響 45
3.5.1雙球體在Re=6.19流場下之溶解 45
3.5.2雙球體在Re=185.58流場下之溶解 51
第四章 結論與未來展望 57
第五章 參考文獻 59
附錄 61

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