楊照彥臺灣大學：應用力學研究所呂李元Lu, Li-YungLi-YungLu2007-11-292018-06-292007-11-292018-06-292007http://ntur.lib.ntu.edu.tw//handle/246246/62479煉鐵工業中，最重要的部分為鐵水來源的高爐製程，過去大多以技師的經驗與技術為依據，若技術交接無法順利傳承給新進技術人員，那麼煉鐵品質將會有所落差，所以現在需要對於高爐製程的內部運作做進一步的瞭解進而對高爐操作參數加以控制。高爐是一個複雜的反應器，爐內具有化學反應與相變化，在此先不考慮化學反應的作用與相變化，主要的探討的內容為固體物料向下滑移情形與氣體在堆料床的流場現象。將高爐內移動的固體堆料床以描述連續體的流體力學方程式加以探討，本文應用Eulerian-Eulerian二相流模型，探討固體與氣體的逆相流行為。而此處固體顆粒之間的作用力除了流體力學中的暫態項與對流向之外再加上動力學中的碰撞效應所造成的摩擦力以及正向力造成的固體壓力關係加以探討。兩相流中的阻力係數應用流體化床領域的Ergun’s equation來探討氣體流經向下移動中的堆料床所造成的作用力。 計算工具為商用軟體ANSYS-CFX，其計算方法為有限體積法，使用SIMPLE與Rhie-Chow的修正方法獲得速度與壓力修正數值，本文模擬高爐內穩態的行為並進一步探討在不同固體顆粒大小分佈的狀態下，對於高爐中固體移動與氣體流場的變化情形產生的影響，做為未來進一步探討高爐內部化學反應及相變化的基礎。Blast furnace plays an important process in the fountainhead of iron and steel industry. In the past, the manufacture process is depending on the technician’s experience and skill. If the guidance of skill is not successfully to make the new technicians understand, the property of steel production will be poor. Nowadays we have to understand the phenomenon inside of blast furnace in order to control the process of steel production. Blast furnace is a complicated reactor which contains chemical reaction and phase transfer. We don't consider the chemical reaction and phase transfer in blast furnace in this research but focus on the motion of solid particles descending and the phenomenon of gas flow in the packed bed. The moving packed bed is discussed by the continuity equation of fluid dynamic. It uses the Eulerian-Eulerian two phase model to discuss the phenomenon of countercurrent flow. It doesn't only discuss the transient and convection part of fluid dynamics but also discuss the particle interaction which is effected by solid collision. The solid collision is from kinetics theory and the effect of solid collision produces the normal force and friction. The drag force between descending packed bed and gas flow is discussed by the drag coefficient of Ergun's equation. The calculation tool is ANSYS-CFX and the numerical method is finite volume method. It uses implicit method to calculate the steady state flow and use the correction method of SIMPLE and Rhie-Chow to obtain the corrected result. This simulation is to discuss the effect of descending solid and gas flow under the different distribution of diameter. It provides the base of further discussion of chemical reaction and phase transfer of blast furnace.誌謝............................................Ⅰ 摘要............................................Ⅱ 目錄............................................Ⅳ 圖目錄..........................................Ⅵ 第一章 緒論 1-1 研究背景...................................1 1-2 文獻回顧...................................3 1-3 本文目的...................................8 第二章 理論基礎 2-1 物理現象...................................9 2-1.1高爐各區域介紹.............................9 2-1.2高爐主要化學反應...........................11 2-1.3高爐相互逆流運作...........................14 2-1.4顆粒流.....................................16 2-2 多相流數學模式.............................20 2-3氣固二相流方程式.............................23 2-3.1 阻力參數..................................24 2-3.2固體碰撞模型...............................26 第三章 研究方法 3-1 數值方法....................................29 3-1.1有限體積法.................................30 3-1.2離散化數值解法.............................31 3-1.3速度與壓力修正.............................33 3.1-4 收斂判斷..................................42 3-2系統模擬建立方法.............................43 3-2.1 模擬幾何形狀..............................43 3-2.2 邊界條件..................................45 第四章 結果與討論 4-1 恢復係數....................................50 4-2顆粒直徑.....................................52 4-3 礦石與焦炭比................................54 4-4 佈料條件....................................56 第五章 結論與未來展望 5-1結論.........................................82 5-2未來展望.....................................84 參考文獻........................................85 圖目錄 圖1-1 不同流體的剪應力與應變關係圖..............6 圖1-2 彈簧阻尼系統探討顆粒作用力模型圖..........7 圖1-3 顆粒正向作用與轉動運動模型................7 圖2-1高爐各區域示意圖...........................10 圖2-2高爐鼓風嘴送風水平截面圖及化學反應示意圖...11 圖2-3高爐化學反應主要分佈區域示意圖.............13 圖2-4高爐操作至穩態的運作圖.....................15 圖2-5高爐內物料分佈對爐氣影響圖.................16 圖2-6顆粒由靜止態至流動態的示意圖...............17 圖2-7 膨脹現象..................................19 圖2-8 控制體積兩相及介面示意圖..................21 圖2-9 雷諾數與阻力係數關係圖....................25 圖2-10 碰撞與動能效應示意圖.....................26 圖 3-1三角體網格示意圖..........................31 圖 3-2 一維離散網格示意圖.......................31 圖 3-3 一維向風差分網格示意圖...................32 圖 3-4 二維交錯網格.............................34 圖 3-5 Multigrid method 虛擬疏鬆網格示意圖......35 圖 3-6 高爐模型與實際計算區域示意圖.............44 圖 3-7 Deadman 輪廓.............................47 圖 3-8 死料區示意圖.............................48 圖 3-9 鼓風區示意圖.............................48 圖 3-10 爐頂示意圖..............................49 圖 3-11 爐壁區示意圖............................49 圖4-1 恢復係數0.5---固體速度輪廓圖與矢量圖......57 圖4-2 恢復係數0.5---氣體速度輪廓圖與矢量圖......58 圖4-3恢復係數0.8---固體速度輪廓圖與矢量圖.......59 圖4-4恢復係數0.8---氣體速度輪廓圖與矢量圖.......60 圖4-5 恢復係數0.5---固體與氣體容積比............61 圖4-6 恢復係數0.8---固體與氣體容積比............62 圖4-7 縮小尺寸的高爐模型---固體速度輪廓圖與矢量圖....63 圖4-8縮小尺寸的高爐模型---氣體速度輪廓圖與矢量圖.....64 圖4-9 等直徑---固體速度輪廓圖與矢量圖...........65 圖4-10 等直徑---氣體速度輪廓圖與矢量圖..........66 圖4-11 顆粒直徑漸增---固體速度輪廓圖與矢量圖....67 圖4-12 顆粒直徑漸增---氣體速度輪廓圖與矢量圖....68 圖4-13 O by C漸增---固體速度輪廓圖與矢量圖......69 圖4-14 O by C漸增---氣體速度輪廓圖與矢量圖......70 圖4-15 O by C漸減---固體速度輪廓圖與矢量圖......71 圖4-16 O by C漸減---氣體速度輪廓圖與矢量圖......72 圖4-17 O by C漸增--密度圖.......................73 圖4-18 O by C漸減--密度圖.......................73 圖4-19 氣體質量流率1 kg/s---固體速度輪廓圖與矢量圖...74 圖4-20 氣體質量流率1 kg/s---氣體速度輪廓圖與矢量圖...75 圖4-21 氣體質量流率10 kg/s---固體速度輪廓圖與矢量圖..76 圖4-22 氣體質量流率10 kg/s---氣體速度輪廓圖與矢量圖..77 圖4-23 固體質量流率3 kg/s---固體速度輪廓圖與矢量圖...78 圖4-24 固體質量流率3 kg/s---氣體速度輪廓圖與矢量圖...79 圖4-25 固體質量流率10 kg/s---固體速度輪廓圖與矢量圖..80 圖4-26 固體質量流率10 kg/s---氣體速度輪廓圖與矢量圖..81en-US高爐逆相流二相流blast furnacecountercurrent flowtwo phase flowthesis